A stabilized finite element algorithm potential for wind-structure interaction(WSI) problem is presented in this paper. Streamline upwind Petrov-Galerkin(SUPG) scheme of the large eddy simulation(LES) of dynamic sub-g...A stabilized finite element algorithm potential for wind-structure interaction(WSI) problem is presented in this paper. Streamline upwind Petrov-Galerkin(SUPG) scheme of the large eddy simulation(LES) of dynamic sub-grid scale(DSGS) is developed under the framework of arbitrary Lagrangian-Eulerian(ALE) description to solve the governing equations. High stabilization is achieved by a three-step technique in the temporal discretization. On the other hand, the partitioned procedure is employed for the consideration of the coupled WSI problem. Newmark integral method is introduced for the computation of structure domain, while spring analogy method is used for the grid update of the mesh domain. The developed computational codes are applied to the analysis of wind-induced effect of a spatial latticed structure. The numerical predictions of the three-dimensional wind flow features, the wind pressures and the wind-induced effect of spatial structures are given. Comparisons are made between the effects of rigid structure in view of the WSI.展开更多
NiTi alloy lattice structures are crucial for reusable energy absorption due to their shape memory effects.However,existing NiTi alloy lattice structures always suffer from localized deformation bands during loading,c...NiTi alloy lattice structures are crucial for reusable energy absorption due to their shape memory effects.However,existing NiTi alloy lattice structures always suffer from localized deformation bands during loading,causing local strains to exceed the recoverable strain limit of the alloy and significantly reducing their reusable energy-absorbing capacity.In this study,we developed a NiTi alloy helical lattice structure(HLS)to effectively prevent localized deformation bands.This is attributed to its struts distributing stress and strain uniformly through torsional deformation,thereby alleviating local stress concentrations and suppressing the formation of localized deformation bands.Additionally,its unit cells provide mutual support and reinforcement during deformation,effectively preventing the progression of localized deformation bands.The NiTi alloy HLS exhibits superior reusable energy absorption compared to previously reported reusable energy-absorbing materials/structures and enhanced damage tolerance under large compression strain.This study provides valuable insights for the development of high-performance reusable NiTi alloy energy-absorbing lattice structures.展开更多
The outstanding comprehensive mechanical properties of newly developed hybrid lattice structures make them useful in engineering applications for bearing multiple mechanical loads.Additive-manufacturing technologies m...The outstanding comprehensive mechanical properties of newly developed hybrid lattice structures make them useful in engineering applications for bearing multiple mechanical loads.Additive-manufacturing technologies make it possible to fabricate these highly spatially programmable structures and greatly enhance the freedom in their design.However,traditional analytical methods do not sufficiently reflect the actual vibration-damping mechanism of lattice structures and are limited by their high computational cost.In this study,a hybrid lattice structure consisting of various cells was designed based on quasi-static and vibration experiments.Subsequently,a novel parametric design method based on a data-driven approach was developed for hybrid lattices with engineered properties.The response surface method was adopted to define the sensitive optimization target.A prediction model for the lattice geometric parameters and vibration properties was established using a backpropagation neural network.Then,it was integrated into the genetic algorithm to create the optimal hybrid lattice with varying geometric features and the required wide-band vibration-damping characteristics.Validation experiments were conducted,demonstrating that the optimized hybrid lattice can achieve the target properties.In addition,the data-driven parametric design method can reduce computation time and be widely applied to complex structural designs when analytical and empirical solutions are unavailable.展开更多
Structural gradient changes are common in nature and play an important role in improving the carrying capacity of organisms.Graded lattice structures designed on this basis have received considerable attention due to ...Structural gradient changes are common in nature and play an important role in improving the carrying capacity of organisms.Graded lattice structures designed on this basis have received considerable attention due to their great design potential.In this study,two different layered gradient design strategies were proposed,and three lattice structures were designed.Samples with PA2200 nylon as the matrix material were prepared using additive manufacturing technology,and finite element models of the relevant lattice structures were established.The mechanical properties and energy absorption ability of the structures under different gradient spans and design strategies were investigated using quasi-static compression tests and numerical simulations.The results indicate that the layered design can improve the elastic modulus of the lattice structure by up to 40.05% and the energy absorption per unit volume by up to 13.04% compared to the conventional body-centered cubic(BCC)structure.However,it is worth noting that an excessively large interlayer gradient span can adversely affect the mechanical properties of the structure.In addition,all layered gradient lattice structures show significant anisotropy,and the energy absorption per unit volume can differ by up to 36.59%under different compression directions.The layered gradient structure design strategies proposed in this work can provide an effective reference for the design of gradient lattice structures.展开更多
Recent advances in additive manufacturing have enabled the construction of metallic lattice structures with tailored mechanical and functional properties.One potential application of metallic lattice struc-tures is in...Recent advances in additive manufacturing have enabled the construction of metallic lattice structures with tailored mechanical and functional properties.One potential application of metallic lattice struc-tures is in the impact load mitigation where an external kinetic energy is absorbed by the deformation/crushing of lattice cells.This has motivated a growing number of experimental and numerical studies,recently,on the crushing behavior of additively produced lattice structures.The present study overviews the dynamic and quasi-static crushing behavior of additively produced Ti64,316L,and AlSiMg alloy lattice structures.The first part of the study summarizes the main features of two most commonly used additive processing techniques for lattice structures,namely selective-laser-melt(SLM)and electro-beam-melt(EBM),along with a description of commonly observed process induced defects.In the second part,the deformation and strain rate sensitivities of the selected alloy lattices are outlined together with the most widely used dynamic test methods,followed by a part on the observed micro-structures of the SLM and EBM-processed Ti64,316L and AlSiMg alloys.Finally,the experimental and numerical studies on the quasi-static and dynamic compression behavior of the additively processed Ti64,316L,and AlSiMg alloy lattices are reviewed.The results of the experimental and numerical studies of the dynamic properties of various types of lattices,including graded,non-uniform strut size,hollow,non-uniform cell size,and bio-inspired,were tabulated together with the used dynamic testing methods.The dynamic tests have been noted to be mostly conducted in compression Split Hopkinson Pressure Bar(SHPB)or Taylor-and direct-impact tests using the SHPB set-up,in all of which relatively small-size test specimens were tested.The test specimen size effect on the compression behavior of the lattices was further emphasized.It has also been shown that the lattices of Ti64 and AlSiMg alloys are relatively brittle as compared with the lattices of 316L alloy.Finally,the challenges associated with modelling lattice structures were explained and the micro tension tests and multi-scale modeling techniques combining microstructural characteristics with macroscopic lattice dynamics were recommended to improve the accuracy of the numerical simulations of the dynamic compression deformations of metallic lattice structures.展开更多
A data-driven model ofmultiple variable cutting(M-VCUT)level set-based substructure is proposed for the topology optimization of lattice structures.TheM-VCUTlevel setmethod is used to represent substructures,enriching...A data-driven model ofmultiple variable cutting(M-VCUT)level set-based substructure is proposed for the topology optimization of lattice structures.TheM-VCUTlevel setmethod is used to represent substructures,enriching their diversity of configuration while ensuring connectivity.To construct the data-driven model of substructure,a database is prepared by sampling the space of substructures spanned by several substructure prototypes.Then,for each substructure in this database,the stiffness matrix is condensed so that its degrees of freedomare reduced.Thereafter,the data-drivenmodel of substructures is constructed through interpolationwith compactly supported radial basis function(CS-RBF).The inputs of the data-driven model are the design variables of topology optimization,and the outputs are the condensed stiffness matrix and volume of substructures.During the optimization,this data-driven model is used,thus avoiding repeated static condensation that would requiremuch computation time.Several numerical examples are provided to verify the proposed method.展开更多
The unit cell configuration of lattice structures critically influences their load-bearing and energy absorption performance.In this study,three novel lattice structures were developed by modifying the conventional FB...The unit cell configuration of lattice structures critically influences their load-bearing and energy absorption performance.In this study,three novel lattice structures were developed by modifying the conventional FBCCZ unit cell through reversing,combining,and turning strategies.The designed lattices were fabricated via laser powder bed fusion(LPBF)using Ti-6Al-4V powder,and the mechanical properties,energy absorption capacity,and deformation behaviors were systematically investigated through quasi-static compression tests and finite element simulations.The results demonstrate that the three modified lattices exhibit superior performance over the conventional FBCCZ structure in terms of fracture strain,specific yield strength,specific ultimate strength,specific energy absorption,and energy absorption efficiency,thereby validating the efficacy of unit cell modifications in enhancing lattice performance.Notably,the CFBCCZ and TFBCCZ lattices significantly outperform both the FBCCZ and RFBCCZ lattice structures in load-bearing and energy absorption.While TFBCCZ shows marginally higher specific elastic modulus and energy absorption efficiency than CFBCCZ,the latter achieves superior energy absorption due to its highest ultimate strength and densification strain.Finite element simulations further reveal that the modified lattices,through optimized redistribution and adjustment of internal nodes and struts,effectively alleviate stress concentration during loading.This structural modification enhances the structural integrity and deformation stability under external loads,enabling a synergistic enhancement of load-bearing capacity and energy absorption performance.展开更多
Titanium/magnesium alloy bimetal composites show promising prospects for lightweight applications.The Ti/Mg bimetal composite was fabricated in Ti−6Al−4V pyramidal lattice structure via AZ91D melt infiltration.Compara...Titanium/magnesium alloy bimetal composites show promising prospects for lightweight applications.The Ti/Mg bimetal composite was fabricated in Ti−6Al−4V pyramidal lattice structure via AZ91D melt infiltration.Comparative analysis of the tensile and compressive properties was conducted between the composite and its constituent materials(Ti−6Al−4V lattice structure and AZ91D matrix).The tensile strength of the composite(95.9 MPa)was comparable to that of the Ti−6Al−4V lattice structure(94.4 MPa)but lower than that of the AZ91D alloy(120.8 MPa)due to gaps at the bimetal interfaces hindering load transfer during tension.The composite exhibited greater elongation(1.7%)compared to AZ91D(1.4%)alloy but less than the Ti−6Al−4V lattice structure(2.6%).The compressive performance of the composite outperformed that of the Ti−6Al−4V lattice structure,underscoring the significance of the AZ91D alloy in compressive deformation.Fracture analysis indicated that the predominant failure reasons in both the composite and lattice structures were attributed to the breakage of lattice struts at nodes caused by the stress concentration.展开更多
This study investigates the dynamic compressive behavior of three periodic lattice structures fabricated from Ti-6Al-4V titanium alloy,each with distinct topologies:simple cubic(SC),body-centered cubic(BCC),and face-c...This study investigates the dynamic compressive behavior of three periodic lattice structures fabricated from Ti-6Al-4V titanium alloy,each with distinct topologies:simple cubic(SC),body-centered cubic(BCC),and face-centered cubic(FCC).Dynamic compression experiments were conducted using a Split Hopkinson Pressure Bar(SHPB)system,complemented by high-speed imaging to capture real-time deformation and failure mechanisms under impact loading.The influence of cell topology,relative density,and strain rate on dynamic mechanical properties,failure behavior,and stress wave propagation was systematically examined.Finite element modeling was performed,and the simulated results showed good agreement with experimental data.The findings reveal that the dynamic mechanical properties of the lattice structures are generally insensitive to strain rate variations,while failure behavior is predominantly governed by structural configuration.The SC structure exhibited strut buckling and instability-induced fracture,whereas the BCC and FCC structures displayed layer-by-layer crushing with lower strain rate sensitivity.Regarding stress wave propagation,all structures demonstrated significant attenuation capabilities,with the BCC structure achieving the greatest reduction in transmitted wave amplitude and energy.Across all configurations,wave reflection was identified as the primary energy dissipation mechanism.These results provide critical insights into the design of lattice structures for impact mitigation and energy absorption applications.展开更多
Metallic lattice structures represent advanced architected materials delivering exceptional properties with promising lightweight potential.With the rapid advancement of additive manufacturing,these structures have ga...Metallic lattice structures represent advanced architected materials delivering exceptional properties with promising lightweight potential.With the rapid advancement of additive manufacturing,these structures have garnered increasing research interest.However,most metallic lattice structures generally exhibit anisotropic characteristics,which limits their application ranges.Additionally,a limited number of studies have successfully developed precise mechanical models,which have undergone experimental validation,for the purpose of describing the mechanical response exhibited by additively manufactured metallic lattice structures.In this study,Kelvin lattice structures with varying porosities were systematically designed and fabricated using laser powder bed fusion(LPBF)technology.By integrating finite element simulations with experimental characterization,an enhanced mechanical model was developed through a modification of the Gibson-Ashby model,providing an accurate quantitative description of the relationship between porosity and mechanical properties.The results show that the revised mechanical model can accurately describe the relationship between the geometric parameters and properties of metallic lattice structures.Specifically,the designed Kelvin lattice structures exhibit a smooth stress-strain curve with an obvious yield platform,demonstrating isotropic mechanical properties in all the three spatial directions.This enhances their suitability for complex loading conditions.Meanwhile,the microstructure and manufacturing accuracy of the Kelvin lattice structures were observed and analyzed by micro computed tomography.The results show that the fabricated metallic lattice structures achieved precise dimensional control and optimal densification.This study presents the complete process involved in modeling the Kelvin structure,including its conceptualization,manufacturing,implementation,and ultimately,disposal.展开更多
High-performance lattice structures produced through powder bed fusion-laser beam exhibit high specific strength and energy absorption capabilities.However,a significant deviation exists between the mechanical propert...High-performance lattice structures produced through powder bed fusion-laser beam exhibit high specific strength and energy absorption capabilities.However,a significant deviation exists between the mechanical properties,service life of lattice structures,and design expectations.This deviation arises from the intense interaction between the laser and powder,which leads to the formation of numerous defects within the lattice structure.To address these issues,this paper proposes a high-performance defect detection model for metal lattice structures based on YOLOv4,called YOLO-Lattice(YOLO-L).The main objectives of this paper are as follows:(1)utilize computed tomography to construct datasets of the diamond lattice and body-centered cubic lattice structures;(2)in the backbone network of YOLOv4,employ deformable convolution to enhance the feature extraction capability of the model for small-scale defects;(3)adopt a dual-attention mechanism to suppress invalid feature information and amplify the distinction between defect and background regions;and(4)implement a channel pruning strategy to eliminate channels carrying less feature information,thereby improving the inference speed of the model.The experimental results on the diamond lattice structure dataset demonstrate that the mean average precision of the YOLO-L model increased from 96.98% to 98.8%(with an intersection over union of 0.5),and the inference speed decreased from 51.3 ms to 32.5 ms when compared to YOLOv4.Thus,the YOLO-L model can be effectively used to detect defects in metal lattice structures.展开更多
Star-shaped lattice structures with a negative Poisson’s ratio(NPR)effect exhibit excellent energy absorption capacity,making them highly promising for applications in aerospace,vehicles,and civil protection.While pr...Star-shaped lattice structures with a negative Poisson’s ratio(NPR)effect exhibit excellent energy absorption capacity,making them highly promising for applications in aerospace,vehicles,and civil protection.While previous research has primarily focused on single-walled cells,there is limited investigation into negative Poisson’s ratio structures with nested multi-walled cells.This study designed three star-shaped cell structures and three lattice configurations,analyzing the Poisson’s ratio,stress–strain relationship,and energy absorption capacity through tensile experiments and finite element simulations.Among the single structures,the star-shaped configuration r3 demonstrated the best elastic modulus,NPR effect,and energy absorption effect.In contrast,the uniform lattice structure R3 exhibited the highest tensile strength and energy absorption capacity.Additionally,the stress intensity and energy absorption of gradient structures increased with the number of layers.This study aims to provide a theoretical reference for the application of NPR materials in safety protection across civil and vehicle engineering,as well as other fields.展开更多
Under strong earthquakes, long-span spatial latticed structures may collapse due to dynamic instability or strength failure. The elasto-plastic dynamic behaviors of three spatial latticed structures, including two dou...Under strong earthquakes, long-span spatial latticed structures may collapse due to dynamic instability or strength failure. The elasto-plastic dynamic behaviors of three spatial latticed structures, including two double-layer cylindrical shells and one spherical shell constructed for the 2008 Olympic Games in Beijing, were quantitatively examined under multi-support excitation （MSE） and uniform support excitation （USE）. In the numerical analyses, several important parameters were investigated such as the peak acceleration and displacement responses at key joints, the number and distribution of plastic members, and the deformation of the shell at the moment of collapse. Analysis results reveal the features and the failure mechanism of the spatial latticed structures under MSE and USE. In both scenarios, the double-layer reticulated shell collapses in the ＂overflow＂ mode, and the collapse is governed by the number of invalid plastic members rather than the total number of plastic members, beginning with damage to some of the local regions near the supports. By comparing the numbers and distributions of the plastic members under MSE to those under USE, it was observed that the plastic members spread more sufficiently and the internal forces are more uniform under MSE, especially in cases of lower apparent velocities in soils. Due to the effects of pseudo-static displacement, the stresses in the members near the supports under MSE are higher than those under USE.展开更多
Laser additive manufacturing (AM) of lattice structures with light weight, excellent impact resistance, and energy absorption performance is receiving considerable attention in aerospace, transportation, and mechanica...Laser additive manufacturing (AM) of lattice structures with light weight, excellent impact resistance, and energy absorption performance is receiving considerable attention in aerospace, transportation, and mechanical equipment application fields. In this study, we designed four gradient lattice structures (GLSs) using the topology optimization method, including the unidirectional GLS, the bi-directional increasing GLS, the bi-directional decreasing GLS and the none-GLS. All GLSs were manufactureed by laser powder bed fusion (LPBF). The uniaxial compression tests and finite element analysis were conducted to investigate the influence of gradient distribution features on deformation modes and energy absorption performance of GLSs. The results showed that, compared with the 45° shear fracture characteristic of the none-GLS, the unidirectional GLS, the bi-directional increasing GLS and the bi-directional decreasing GLS had the characteristics of the layer-by-layer fracture, showing considerably improved energy absorption capacity. The bi-directional increasing GLS showed a unique combination of shear fracture and layer-by-layer fracture, having the optimal energy absorption performance with energy absorption and specific energy absorption of 235.6 J and 9.5 J g-1 at 0.5 strain, respectively. Combined with the shape memory effect of NiTi alloy, multiple compression-heat recovery experiments were carried out to verify the shape memory function of LPBF-processed NiTi GLSs. These findings have potential value for the future design of GLSs and the realization of shape memory function of NiTi components through laser AM.展开更多
Digital light processing technique was applied to manufacture alumina ceramic parts with two types of lattice structure units, i.e. vertex interconnect structure and edge structure. The internal porosity of the unit i...Digital light processing technique was applied to manufacture alumina ceramic parts with two types of lattice structure units, i.e. vertex interconnect structure and edge structure. The internal porosity of the unit is 40%. The printed parts were sintered and the grain size is about 1.1 μm. The bending strength of the vertex interconnect structure is much larger than that of the edge structure. Materials genome initiative(MGI) aims to digital design and intelligent manufacture for advanced components. This research shows us an example to achieve this goal.展开更多
This paper presents a novel topology optimization method to design graded lattice structures to minimize the volume subject to displacement constraints based on the independent continuous mapping(ICM)method.First,the ...This paper presents a novel topology optimization method to design graded lattice structures to minimize the volume subject to displacement constraints based on the independent continuous mapping(ICM)method.First,the effective elastic properties of graded unit cells are analyzed by the strain energy-based homogenization method.A surrogate model using quartic polynomial interpolation is built to map the independent continuous topological variable to the effective elastic matrix of the unit cell and set up the relationship between the macroscale structure and microscale unit cells.Second,a lightweight topology optimization model is established,which can be transformed into an explicitly standard quadratic programming problem by sensitivity analysis and solved by dual sequential quadratic programming.Third,several numerical examples demonstrate that graded lattice structures have a better lightweight effect than uniform lattice structures,which validates the effectiveness and feasibility of the proposed method.The results show that graded lattice structures become lighter with increasing displacement constraints.In addition,some diverse topological configurations are obtained.This method provides a reference for the graded lattice structure design and expands the application of the ICM method.展开更多
Inspired by the gradient structure of the nature,two gradient lattice structures,i.e.,unidirectional gradient lattice(UGL)and bidirectional gradient lattice(BGL),are proposed based on the body-centered cubic(BCC)latti...Inspired by the gradient structure of the nature,two gradient lattice structures,i.e.,unidirectional gradient lattice(UGL)and bidirectional gradient lattice(BGL),are proposed based on the body-centered cubic(BCC)lattice to obtain specially designed mechanical behaviors,such as load-bearing and energy absorption capacities.First,a theoretical model is proposed to predict the initial stiffness of the gradient lattice structure under compressive loading,and validated against quasi-static compression tests and finite element models(FEMs).The deformation and failure mechanisms of the two structures are further studied based on experiments and simulations.The UGL structure exhibits a layer-by-layer failure mode,which avoids structure-wise shear failure in uniform structures.The BGL structure presents a symmetry deformation pattern,and the failure initiates at the weakest part.Finally,the energy absorption behaviors are also discussed.This study demonstrates the potential application of gradient lattice structures in load-transfer-path modification and energy absorption by topology design.展开更多
Lattice structures have drawn much attention in engineering applications due to their lightweight and multi-functional properties.In this work,a mathematical design approach for functionally graded(FG)and helicoidal l...Lattice structures have drawn much attention in engineering applications due to their lightweight and multi-functional properties.In this work,a mathematical design approach for functionally graded(FG)and helicoidal lattice structures with triply periodic minimal surfaces is proposed.Four types of lattice structures including uniform,helicoidal,FG,and combined FG and helicoidal are fabricated by the additive manufacturing technology.The deformation behaviors,mechanical properties,energy absorption,and acoustic properties of lattice samples are thoroughly investigated.The load-bearing capability of helicoidal lattice samples is gradually improved in the plateau stage,leading to the plateau stress and total energy absorption improved by over 26.9%and 21.2%compared to the uniform sample,respectively.This phenomenon was attributed to the helicoidal design reduces the gap in unit cells and enhances fracture resistance.For acoustic properties,the design of helicoidal reduces the resonance frequency and improves the peak of absorption coefficient,while the FG design mainly influences the peak of absorption coefficient.Across broad range of frequency from 1000 to 6300 Hz,the maximum value of absorption coefficient is improved by18.6%-30%,and the number of points higher than 0.6 increased by 55.2%-61.7%by combining the FG and helicoidal designs.This study provides a novel strategy to simultaneously improve energy absorption and sound absorption properties by controlling the internal architecture of lattice structures.展开更多
Ceramic cores are widely used in investment casting,and ideal properties of cores are essential for high-quality castings.Under the circumstances requiring thick cores,solid cores are likely to encounter deformation a...Ceramic cores are widely used in investment casting,and ideal properties of cores are essential for high-quality castings.Under the circumstances requiring thick cores,solid cores are likely to encounter deformation and cracking defects due to the accumulation of shrinkage.Therefore,with the superiority of ceramic stereolithography in producing complex ceramic parts,hollow cores with lattice structures were designed and fabricated.The dimensional accuracy and properties of the green and sintered bodies were evaluated.Results show the dimensional accuracy of sintered cores is controlled within±0.25 mm benefited from the precise green bodies.The mechanical properties are not obviously deteriorated.The bending strength reaches 11.94 MPa at room temperature and 12.87 MPa at 1,500℃ with a creep deformation of 0.345 mm.Furthermore,casting verifications prove that the hollow cores meet the requirements of investment casting.Smooth casting surfaces are obtained,at the same time,the core-removal efficiency is improved by over 3 times.展开更多
Nickel-based superalloy lattice sandwich structures present higher stiffness,higher strength and higher temperature resistance in comparison with other metals.In this study,the Kagome unit was adopted to design the la...Nickel-based superalloy lattice sandwich structures present higher stiffness,higher strength and higher temperature resistance in comparison with other metals.In this study,the Kagome unit was adopted to design the lattice sandwich structure and ProCAST software was used to simulate the filling and solidification processes of the nickel-based superalloy.Grain morphology and sizes of the nickel-based superalloy lattice sandwich structures were simulated by using of cellular automaton coupled with finite element model(CAFE),and indirect additive manufacture combining with investment casting were carried out to fabricate the nickel-based superalloy lattice sandwich structures.The calculated grain morphology and sizes are in good agreement with the experimental results.The grains are mainly equiaxed with an average size of about 500µm.The simulated results also show that the superheat of melting and the mold preheated temperature have significant influence on the grain size of the Kagome lattice sandwich structures,lower superheat of melting and mold preheated temperatures are encouraged to obtain the fine grains while assuring the integrity of the Kagome lattice sandwich structures for industrial application.展开更多
基金the National Natural Science Foundation of China(Nos.11172174 and 51278297)the Research Program of Shanghai Leader Talent(No.20)the Doctoral Disciplinary Special Research Project of Chinese Ministry of Education(No.20130073110096)
文摘A stabilized finite element algorithm potential for wind-structure interaction(WSI) problem is presented in this paper. Streamline upwind Petrov-Galerkin(SUPG) scheme of the large eddy simulation(LES) of dynamic sub-grid scale(DSGS) is developed under the framework of arbitrary Lagrangian-Eulerian(ALE) description to solve the governing equations. High stabilization is achieved by a three-step technique in the temporal discretization. On the other hand, the partitioned procedure is employed for the consideration of the coupled WSI problem. Newmark integral method is introduced for the computation of structure domain, while spring analogy method is used for the grid update of the mesh domain. The developed computational codes are applied to the analysis of wind-induced effect of a spatial latticed structure. The numerical predictions of the three-dimensional wind flow features, the wind pressures and the wind-induced effect of spatial structures are given. Comparisons are made between the effects of rigid structure in view of the WSI.
基金financially supported by the National Key R&D Program of China(No.2022YFB4600500)the National Safety Academic Fund(Nos.U2130201 and U2330105).
文摘NiTi alloy lattice structures are crucial for reusable energy absorption due to their shape memory effects.However,existing NiTi alloy lattice structures always suffer from localized deformation bands during loading,causing local strains to exceed the recoverable strain limit of the alloy and significantly reducing their reusable energy-absorbing capacity.In this study,we developed a NiTi alloy helical lattice structure(HLS)to effectively prevent localized deformation bands.This is attributed to its struts distributing stress and strain uniformly through torsional deformation,thereby alleviating local stress concentrations and suppressing the formation of localized deformation bands.Additionally,its unit cells provide mutual support and reinforcement during deformation,effectively preventing the progression of localized deformation bands.The NiTi alloy HLS exhibits superior reusable energy absorption compared to previously reported reusable energy-absorbing materials/structures and enhanced damage tolerance under large compression strain.This study provides valuable insights for the development of high-performance reusable NiTi alloy energy-absorbing lattice structures.
基金supported by National Natural Science Foundation of China(Grant No.52375380)National Key R&D Program of China(Grant No.2022YFB3402200)the Key Project of National Natural Science Foundation of China(Grant No.12032018).
文摘The outstanding comprehensive mechanical properties of newly developed hybrid lattice structures make them useful in engineering applications for bearing multiple mechanical loads.Additive-manufacturing technologies make it possible to fabricate these highly spatially programmable structures and greatly enhance the freedom in their design.However,traditional analytical methods do not sufficiently reflect the actual vibration-damping mechanism of lattice structures and are limited by their high computational cost.In this study,a hybrid lattice structure consisting of various cells was designed based on quasi-static and vibration experiments.Subsequently,a novel parametric design method based on a data-driven approach was developed for hybrid lattices with engineered properties.The response surface method was adopted to define the sensitive optimization target.A prediction model for the lattice geometric parameters and vibration properties was established using a backpropagation neural network.Then,it was integrated into the genetic algorithm to create the optimal hybrid lattice with varying geometric features and the required wide-band vibration-damping characteristics.Validation experiments were conducted,demonstrating that the optimized hybrid lattice can achieve the target properties.In addition,the data-driven parametric design method can reduce computation time and be widely applied to complex structural designs when analytical and empirical solutions are unavailable.
基金supported by National Natural Science Foundation of China(Grant Nos.12172067,12072052,12372128,12072005,U23A2067)Fundamental Research Funds for the Central Universities(Grant Nos.2024CDJXY009,2022CDJQY-004)+3 种基金Aeronautical Science Foundation of China(Grant No.2022Z0570Q9002)Chongqing Talent Plan(Grant No.cstc2022ycjh-bgzxm0144)Young Elite Scientists Sponsorship Program by CAST(Grant No.2020QNRC001)Xiaomi Young Talents Program.
文摘Structural gradient changes are common in nature and play an important role in improving the carrying capacity of organisms.Graded lattice structures designed on this basis have received considerable attention due to their great design potential.In this study,two different layered gradient design strategies were proposed,and three lattice structures were designed.Samples with PA2200 nylon as the matrix material were prepared using additive manufacturing technology,and finite element models of the relevant lattice structures were established.The mechanical properties and energy absorption ability of the structures under different gradient spans and design strategies were investigated using quasi-static compression tests and numerical simulations.The results indicate that the layered design can improve the elastic modulus of the lattice structure by up to 40.05% and the energy absorption per unit volume by up to 13.04% compared to the conventional body-centered cubic(BCC)structure.However,it is worth noting that an excessively large interlayer gradient span can adversely affect the mechanical properties of the structure.In addition,all layered gradient lattice structures show significant anisotropy,and the energy absorption per unit volume can differ by up to 36.59%under different compression directions.The layered gradient structure design strategies proposed in this work can provide an effective reference for the design of gradient lattice structures.
基金the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 101034425 for the project titled A2M2TECHThe Scientific and Technological Research Council of Türkiye (TUBITAK) with grant No 120C158 for the same A2M2TECH project under the TUBITAK's 2236/B program
文摘Recent advances in additive manufacturing have enabled the construction of metallic lattice structures with tailored mechanical and functional properties.One potential application of metallic lattice struc-tures is in the impact load mitigation where an external kinetic energy is absorbed by the deformation/crushing of lattice cells.This has motivated a growing number of experimental and numerical studies,recently,on the crushing behavior of additively produced lattice structures.The present study overviews the dynamic and quasi-static crushing behavior of additively produced Ti64,316L,and AlSiMg alloy lattice structures.The first part of the study summarizes the main features of two most commonly used additive processing techniques for lattice structures,namely selective-laser-melt(SLM)and electro-beam-melt(EBM),along with a description of commonly observed process induced defects.In the second part,the deformation and strain rate sensitivities of the selected alloy lattices are outlined together with the most widely used dynamic test methods,followed by a part on the observed micro-structures of the SLM and EBM-processed Ti64,316L and AlSiMg alloys.Finally,the experimental and numerical studies on the quasi-static and dynamic compression behavior of the additively processed Ti64,316L,and AlSiMg alloy lattices are reviewed.The results of the experimental and numerical studies of the dynamic properties of various types of lattices,including graded,non-uniform strut size,hollow,non-uniform cell size,and bio-inspired,were tabulated together with the used dynamic testing methods.The dynamic tests have been noted to be mostly conducted in compression Split Hopkinson Pressure Bar(SHPB)or Taylor-and direct-impact tests using the SHPB set-up,in all of which relatively small-size test specimens were tested.The test specimen size effect on the compression behavior of the lattices was further emphasized.It has also been shown that the lattices of Ti64 and AlSiMg alloys are relatively brittle as compared with the lattices of 316L alloy.Finally,the challenges associated with modelling lattice structures were explained and the micro tension tests and multi-scale modeling techniques combining microstructural characteristics with macroscopic lattice dynamics were recommended to improve the accuracy of the numerical simulations of the dynamic compression deformations of metallic lattice structures.
基金supported by the National Natural Science Foundation of China(Grant No.12272144).
文摘A data-driven model ofmultiple variable cutting(M-VCUT)level set-based substructure is proposed for the topology optimization of lattice structures.TheM-VCUTlevel setmethod is used to represent substructures,enriching their diversity of configuration while ensuring connectivity.To construct the data-driven model of substructure,a database is prepared by sampling the space of substructures spanned by several substructure prototypes.Then,for each substructure in this database,the stiffness matrix is condensed so that its degrees of freedomare reduced.Thereafter,the data-drivenmodel of substructures is constructed through interpolationwith compactly supported radial basis function(CS-RBF).The inputs of the data-driven model are the design variables of topology optimization,and the outputs are the condensed stiffness matrix and volume of substructures.During the optimization,this data-driven model is used,thus avoiding repeated static condensation that would requiremuch computation time.Several numerical examples are provided to verify the proposed method.
基金supported by National Key Lab of Aerospace Power System and Plasma Technology Foundation of China(Grant No.APSPT202301002)National Natural Science Foundation of China(Grant No.52001038)Natural Science Foundation of Chongqing,China(Grant Nos.cstc2019jcyj-msxm X0787 and cstc2021jcyj-msxm X0011)。
文摘The unit cell configuration of lattice structures critically influences their load-bearing and energy absorption performance.In this study,three novel lattice structures were developed by modifying the conventional FBCCZ unit cell through reversing,combining,and turning strategies.The designed lattices were fabricated via laser powder bed fusion(LPBF)using Ti-6Al-4V powder,and the mechanical properties,energy absorption capacity,and deformation behaviors were systematically investigated through quasi-static compression tests and finite element simulations.The results demonstrate that the three modified lattices exhibit superior performance over the conventional FBCCZ structure in terms of fracture strain,specific yield strength,specific ultimate strength,specific energy absorption,and energy absorption efficiency,thereby validating the efficacy of unit cell modifications in enhancing lattice performance.Notably,the CFBCCZ and TFBCCZ lattices significantly outperform both the FBCCZ and RFBCCZ lattice structures in load-bearing and energy absorption.While TFBCCZ shows marginally higher specific elastic modulus and energy absorption efficiency than CFBCCZ,the latter achieves superior energy absorption due to its highest ultimate strength and densification strain.Finite element simulations further reveal that the modified lattices,through optimized redistribution and adjustment of internal nodes and struts,effectively alleviate stress concentration during loading.This structural modification enhances the structural integrity and deformation stability under external loads,enabling a synergistic enhancement of load-bearing capacity and energy absorption performance.
基金the financial support from the National Natural Science Foundation of China(Nos.51875062,52205336)。
文摘Titanium/magnesium alloy bimetal composites show promising prospects for lightweight applications.The Ti/Mg bimetal composite was fabricated in Ti−6Al−4V pyramidal lattice structure via AZ91D melt infiltration.Comparative analysis of the tensile and compressive properties was conducted between the composite and its constituent materials(Ti−6Al−4V lattice structure and AZ91D matrix).The tensile strength of the composite(95.9 MPa)was comparable to that of the Ti−6Al−4V lattice structure(94.4 MPa)but lower than that of the AZ91D alloy(120.8 MPa)due to gaps at the bimetal interfaces hindering load transfer during tension.The composite exhibited greater elongation(1.7%)compared to AZ91D(1.4%)alloy but less than the Ti−6Al−4V lattice structure(2.6%).The compressive performance of the composite outperformed that of the Ti−6Al−4V lattice structure,underscoring the significance of the AZ91D alloy in compressive deformation.Fracture analysis indicated that the predominant failure reasons in both the composite and lattice structures were attributed to the breakage of lattice struts at nodes caused by the stress concentration.
基金supported by the National Natural Science Foundations of China(No.11972267 and 11802214)the Fundamental Research Funds for the Central Universities(No.104972024JYS0022)the Open Fund of the Hubei Longzhong Laboratory(No.2024KF-30).
文摘This study investigates the dynamic compressive behavior of three periodic lattice structures fabricated from Ti-6Al-4V titanium alloy,each with distinct topologies:simple cubic(SC),body-centered cubic(BCC),and face-centered cubic(FCC).Dynamic compression experiments were conducted using a Split Hopkinson Pressure Bar(SHPB)system,complemented by high-speed imaging to capture real-time deformation and failure mechanisms under impact loading.The influence of cell topology,relative density,and strain rate on dynamic mechanical properties,failure behavior,and stress wave propagation was systematically examined.Finite element modeling was performed,and the simulated results showed good agreement with experimental data.The findings reveal that the dynamic mechanical properties of the lattice structures are generally insensitive to strain rate variations,while failure behavior is predominantly governed by structural configuration.The SC structure exhibited strut buckling and instability-induced fracture,whereas the BCC and FCC structures displayed layer-by-layer crushing with lower strain rate sensitivity.Regarding stress wave propagation,all structures demonstrated significant attenuation capabilities,with the BCC structure achieving the greatest reduction in transmitted wave amplitude and energy.Across all configurations,wave reflection was identified as the primary energy dissipation mechanism.These results provide critical insights into the design of lattice structures for impact mitigation and energy absorption applications.
基金financially supported by the Liaoning Province Applied Fundamental Research Program (No.2023JH2/101700039)Liaoning Province Natural Science Foundation (No.2023-MSLH-328).
文摘Metallic lattice structures represent advanced architected materials delivering exceptional properties with promising lightweight potential.With the rapid advancement of additive manufacturing,these structures have garnered increasing research interest.However,most metallic lattice structures generally exhibit anisotropic characteristics,which limits their application ranges.Additionally,a limited number of studies have successfully developed precise mechanical models,which have undergone experimental validation,for the purpose of describing the mechanical response exhibited by additively manufactured metallic lattice structures.In this study,Kelvin lattice structures with varying porosities were systematically designed and fabricated using laser powder bed fusion(LPBF)technology.By integrating finite element simulations with experimental characterization,an enhanced mechanical model was developed through a modification of the Gibson-Ashby model,providing an accurate quantitative description of the relationship between porosity and mechanical properties.The results show that the revised mechanical model can accurately describe the relationship between the geometric parameters and properties of metallic lattice structures.Specifically,the designed Kelvin lattice structures exhibit a smooth stress-strain curve with an obvious yield platform,demonstrating isotropic mechanical properties in all the three spatial directions.This enhances their suitability for complex loading conditions.Meanwhile,the microstructure and manufacturing accuracy of the Kelvin lattice structures were observed and analyzed by micro computed tomography.The results show that the fabricated metallic lattice structures achieved precise dimensional control and optimal densification.This study presents the complete process involved in modeling the Kelvin structure,including its conceptualization,manufacturing,implementation,and ultimately,disposal.
基金supported by Natural Science Foundation of China(Grant No.52175488)Scientific Research Program for Young Outstanding Talent of Higher Education of Hebei Province(China)(Grant No.BJ2021045)S&T Program of Hebei(China)(Grant No.236Z1808G).
文摘High-performance lattice structures produced through powder bed fusion-laser beam exhibit high specific strength and energy absorption capabilities.However,a significant deviation exists between the mechanical properties,service life of lattice structures,and design expectations.This deviation arises from the intense interaction between the laser and powder,which leads to the formation of numerous defects within the lattice structure.To address these issues,this paper proposes a high-performance defect detection model for metal lattice structures based on YOLOv4,called YOLO-Lattice(YOLO-L).The main objectives of this paper are as follows:(1)utilize computed tomography to construct datasets of the diamond lattice and body-centered cubic lattice structures;(2)in the backbone network of YOLOv4,employ deformable convolution to enhance the feature extraction capability of the model for small-scale defects;(3)adopt a dual-attention mechanism to suppress invalid feature information and amplify the distinction between defect and background regions;and(4)implement a channel pruning strategy to eliminate channels carrying less feature information,thereby improving the inference speed of the model.The experimental results on the diamond lattice structure dataset demonstrate that the mean average precision of the YOLO-L model increased from 96.98% to 98.8%(with an intersection over union of 0.5),and the inference speed decreased from 51.3 ms to 32.5 ms when compared to YOLOv4.Thus,the YOLO-L model can be effectively used to detect defects in metal lattice structures.
基金support of the National Natural Science Foundation of China(12202038)the Fundamental Research Funds for the Central Universities(FRF-TP-22-028A1).
文摘Star-shaped lattice structures with a negative Poisson’s ratio(NPR)effect exhibit excellent energy absorption capacity,making them highly promising for applications in aerospace,vehicles,and civil protection.While previous research has primarily focused on single-walled cells,there is limited investigation into negative Poisson’s ratio structures with nested multi-walled cells.This study designed three star-shaped cell structures and three lattice configurations,analyzing the Poisson’s ratio,stress–strain relationship,and energy absorption capacity through tensile experiments and finite element simulations.Among the single structures,the star-shaped configuration r3 demonstrated the best elastic modulus,NPR effect,and energy absorption effect.In contrast,the uniform lattice structure R3 exhibited the highest tensile strength and energy absorption capacity.Additionally,the stress intensity and energy absorption of gradient structures increased with the number of layers.This study aims to provide a theoretical reference for the application of NPR materials in safety protection across civil and vehicle engineering,as well as other fields.
文摘Under strong earthquakes, long-span spatial latticed structures may collapse due to dynamic instability or strength failure. The elasto-plastic dynamic behaviors of three spatial latticed structures, including two double-layer cylindrical shells and one spherical shell constructed for the 2008 Olympic Games in Beijing, were quantitatively examined under multi-support excitation （MSE） and uniform support excitation （USE）. In the numerical analyses, several important parameters were investigated such as the peak acceleration and displacement responses at key joints, the number and distribution of plastic members, and the deformation of the shell at the moment of collapse. Analysis results reveal the features and the failure mechanism of the spatial latticed structures under MSE and USE. In both scenarios, the double-layer reticulated shell collapses in the ＂overflow＂ mode, and the collapse is governed by the number of invalid plastic members rather than the total number of plastic members, beginning with damage to some of the local regions near the supports. By comparing the numbers and distributions of the plastic members under MSE to those under USE, it was observed that the plastic members spread more sufficiently and the internal forces are more uniform under MSE, especially in cases of lower apparent velocities in soils. Due to the effects of pseudo-static displacement, the stresses in the members near the supports under MSE are higher than those under USE.
基金supported by the financial support from the National Natural Science Foundation of China(Nos.51735005 and U1930207)the Basic Strengthening Program(No.2019-JCJQ-JJ-331)+1 种基金National Natural Science Founda-tion of China for Creative Research Groups(No.51921003)the 15th Batch of‘Six Talents Peaks’Innovative Talents Team Program(No.TD-GDZB-001).
文摘Laser additive manufacturing (AM) of lattice structures with light weight, excellent impact resistance, and energy absorption performance is receiving considerable attention in aerospace, transportation, and mechanical equipment application fields. In this study, we designed four gradient lattice structures (GLSs) using the topology optimization method, including the unidirectional GLS, the bi-directional increasing GLS, the bi-directional decreasing GLS and the none-GLS. All GLSs were manufactureed by laser powder bed fusion (LPBF). The uniaxial compression tests and finite element analysis were conducted to investigate the influence of gradient distribution features on deformation modes and energy absorption performance of GLSs. The results showed that, compared with the 45° shear fracture characteristic of the none-GLS, the unidirectional GLS, the bi-directional increasing GLS and the bi-directional decreasing GLS had the characteristics of the layer-by-layer fracture, showing considerably improved energy absorption capacity. The bi-directional increasing GLS showed a unique combination of shear fracture and layer-by-layer fracture, having the optimal energy absorption performance with energy absorption and specific energy absorption of 235.6 J and 9.5 J g-1 at 0.5 strain, respectively. Combined with the shape memory effect of NiTi alloy, multiple compression-heat recovery experiments were carried out to verify the shape memory function of LPBF-processed NiTi GLSs. These findings have potential value for the future design of GLSs and the realization of shape memory function of NiTi components through laser AM.
基金the National Key R&D Program of China (Grants Nos. 2017YFB0703200, 2016YFB0700500)the National Natural Science Foundation of China (Grants Nos.51372203, 51332004, 51571166, 51972268 and 51761135032)the Foreign Talents Introduction and Academic Exchange Program (Grant No. B08040) for their financial supports
文摘Digital light processing technique was applied to manufacture alumina ceramic parts with two types of lattice structure units, i.e. vertex interconnect structure and edge structure. The internal porosity of the unit is 40%. The printed parts were sintered and the grain size is about 1.1 μm. The bending strength of the vertex interconnect structure is much larger than that of the edge structure. Materials genome initiative(MGI) aims to digital design and intelligent manufacture for advanced components. This research shows us an example to achieve this goal.
基金the National Natural Science Foundation of China(Grant No.11872080)Beijing Natural Science Foundation(Grant No.3192005)Taishan University Youth Teacher Science Foundation(Grant No.QN-01-201901).
文摘This paper presents a novel topology optimization method to design graded lattice structures to minimize the volume subject to displacement constraints based on the independent continuous mapping(ICM)method.First,the effective elastic properties of graded unit cells are analyzed by the strain energy-based homogenization method.A surrogate model using quartic polynomial interpolation is built to map the independent continuous topological variable to the effective elastic matrix of the unit cell and set up the relationship between the macroscale structure and microscale unit cells.Second,a lightweight topology optimization model is established,which can be transformed into an explicitly standard quadratic programming problem by sensitivity analysis and solved by dual sequential quadratic programming.Third,several numerical examples demonstrate that graded lattice structures have a better lightweight effect than uniform lattice structures,which validates the effectiveness and feasibility of the proposed method.The results show that graded lattice structures become lighter with increasing displacement constraints.In addition,some diverse topological configurations are obtained.This method provides a reference for the graded lattice structure design and expands the application of the ICM method.
基金the National Natural Science Foundation of China(Grant Nos.11972049 and 12002050)National Key Laboratory Foundation of Science and Technology on Materials under Shock and Im-pact(Grant No.6142902200401)Opening Fund of State Key Laboratory of Nonlinear Mechanics.
文摘Inspired by the gradient structure of the nature,two gradient lattice structures,i.e.,unidirectional gradient lattice(UGL)and bidirectional gradient lattice(BGL),are proposed based on the body-centered cubic(BCC)lattice to obtain specially designed mechanical behaviors,such as load-bearing and energy absorption capacities.First,a theoretical model is proposed to predict the initial stiffness of the gradient lattice structure under compressive loading,and validated against quasi-static compression tests and finite element models(FEMs).The deformation and failure mechanisms of the two structures are further studied based on experiments and simulations.The UGL structure exhibits a layer-by-layer failure mode,which avoids structure-wise shear failure in uniform structures.The BGL structure presents a symmetry deformation pattern,and the failure initiates at the weakest part.Finally,the energy absorption behaviors are also discussed.This study demonstrates the potential application of gradient lattice structures in load-transfer-path modification and energy absorption by topology design.
基金supported by the NUS R&G Postdoc Fellowship Program (No.A-0000065-76-00)the China Scholarship Council (No.202006050088)。
文摘Lattice structures have drawn much attention in engineering applications due to their lightweight and multi-functional properties.In this work,a mathematical design approach for functionally graded(FG)and helicoidal lattice structures with triply periodic minimal surfaces is proposed.Four types of lattice structures including uniform,helicoidal,FG,and combined FG and helicoidal are fabricated by the additive manufacturing technology.The deformation behaviors,mechanical properties,energy absorption,and acoustic properties of lattice samples are thoroughly investigated.The load-bearing capability of helicoidal lattice samples is gradually improved in the plateau stage,leading to the plateau stress and total energy absorption improved by over 26.9%and 21.2%compared to the uniform sample,respectively.This phenomenon was attributed to the helicoidal design reduces the gap in unit cells and enhances fracture resistance.For acoustic properties,the design of helicoidal reduces the resonance frequency and improves the peak of absorption coefficient,while the FG design mainly influences the peak of absorption coefficient.Across broad range of frequency from 1000 to 6300 Hz,the maximum value of absorption coefficient is improved by18.6%-30%,and the number of points higher than 0.6 increased by 55.2%-61.7%by combining the FG and helicoidal designs.This study provides a novel strategy to simultaneously improve energy absorption and sound absorption properties by controlling the internal architecture of lattice structures.
基金supported by the National Natural Science Foundation of China (Grant No. 52175333)Tribology Science Fund of the State Key Laboratory of Tribology,Tsinghua University (Grant No. SKLT2021B05)+1 种基金Foshan Science and Technology Innovation Team Project (Grant No. 2018IT100142)National Science and Technology Major Project of China (Grant No. J2019-VII-0002-0142)
文摘Ceramic cores are widely used in investment casting,and ideal properties of cores are essential for high-quality castings.Under the circumstances requiring thick cores,solid cores are likely to encounter deformation and cracking defects due to the accumulation of shrinkage.Therefore,with the superiority of ceramic stereolithography in producing complex ceramic parts,hollow cores with lattice structures were designed and fabricated.The dimensional accuracy and properties of the green and sintered bodies were evaluated.Results show the dimensional accuracy of sintered cores is controlled within±0.25 mm benefited from the precise green bodies.The mechanical properties are not obviously deteriorated.The bending strength reaches 11.94 MPa at room temperature and 12.87 MPa at 1,500℃ with a creep deformation of 0.345 mm.Furthermore,casting verifications prove that the hollow cores meet the requirements of investment casting.Smooth casting surfaces are obtained,at the same time,the core-removal efficiency is improved by over 3 times.
基金financially supported by the National Science and Technology Major Project of China(No.2017ZA04014001)the Natural Science Foundation of Liaoning Province of China(Nos.2019-ZD-0997,20170540890)the Technology Development Fund of China Academy of Machinery Science and Technology(No.170217ZS01)
文摘Nickel-based superalloy lattice sandwich structures present higher stiffness,higher strength and higher temperature resistance in comparison with other metals.In this study,the Kagome unit was adopted to design the lattice sandwich structure and ProCAST software was used to simulate the filling and solidification processes of the nickel-based superalloy.Grain morphology and sizes of the nickel-based superalloy lattice sandwich structures were simulated by using of cellular automaton coupled with finite element model(CAFE),and indirect additive manufacture combining with investment casting were carried out to fabricate the nickel-based superalloy lattice sandwich structures.The calculated grain morphology and sizes are in good agreement with the experimental results.The grains are mainly equiaxed with an average size of about 500µm.The simulated results also show that the superheat of melting and the mold preheated temperature have significant influence on the grain size of the Kagome lattice sandwich structures,lower superheat of melting and mold preheated temperatures are encouraged to obtain the fine grains while assuring the integrity of the Kagome lattice sandwich structures for industrial application.
