Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability an...Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.展开更多
Design a precision electroplating mechanical structure for automobiles based on finite element analysis method and analyze its mechanical properties.Taking the automobile steering knuckle as the research object,ABAQUS...Design a precision electroplating mechanical structure for automobiles based on finite element analysis method and analyze its mechanical properties.Taking the automobile steering knuckle as the research object,ABAQUS parametric modeling technology is used to construct its three-dimensional geometric model,and geometric simplification is carried out.Two surface treatment processes,HK-35 zinc nickel alloy electroplating and pure zinc electroplating,were designed,and the influence of different coatings on the mechanical properties of steering knuckles was compared and analyzed through numerical simulation.At the same time,standard specimens were prepared for salt spray corrosion testing and scratch method combined strength testing to verify the numerical simulation results.The results showed that under emergency braking and composite working conditions,the peak Von Mises stress of the zinc nickel alloy coating was 119.85 MPa,which was lower than that of the pure zinc coating and the alkaline electroplated zinc layer.Its equivalent strain value was 652×10^(-6),which was lower than that of the pure zinc coating and the alkaline electroplated zinc layer.Experimental data confirms that zinc nickel alloy coatings exhibit significant advantages in stress distribution uniformity,strain performance,and load-bearing capacity in high stress zones.The salt spray corrosion test further indicates that the coating has superior corrosion resistance and coating substrate interface bonding strength,which can significantly improve the mechanical stability and long-term reliability of automotive precision electroplating mechanical structures.展开更多
Objective: To compare the stress distribution in the periodontal ligament under different orthodontic forces during canine distalization using long-arm brackets, and to determine the optimal force value for this devic...Objective: To compare the stress distribution in the periodontal ligament under different orthodontic forces during canine distalization using long-arm brackets, and to determine the optimal force value for this device in orthodontic treatment. Methods: A finite element model was constructed after extracting the mandibular first premolar, and a long-arm bracket with a traction height of 6 mm was placed on the labial side of the mandibular canine. Three working conditions of 50 g, 100 g, and 150 g were simulated, and the magnitude and distribution of von Mises stress in the periodontal ligament were compared for each condition. Results: The maximum von Mises stress in the periodontal ligament was 0.013281 MPa in the 50 g condition, 0.02536 MPa in the 100 g condition, and 0.035549 MPa in the 150 g condition. As the orthodontic force increased, the stress distribution area in the periodontal ligament also expanded. Conclusion: A 100 g orthodontic force is the most suitable when using long-arm brackets, providing a relatively uniform stress distribution in the periodontal ligament and keeping the stress within a reasonable range.展开更多
[Objectives]To investigate the content and distribution of inorganic elements in Astragalus membranaceus sourced from various regions in Gansu Province.[Methods]28 batches of A.membranaceus samples were collected and ...[Objectives]To investigate the content and distribution of inorganic elements in Astragalus membranaceus sourced from various regions in Gansu Province.[Methods]28 batches of A.membranaceus samples were collected and subsequently digested using the Multiwave 7000 super microwave digestion system.The contents of aluminum(Al),barium(Ba),beryllium(Be),cobalt(Co),chromium(Cr),iron(Fe),gallium(Ga),magnesium(Mg),manganese(Mn),nickel(Ni),antimony(Sb),tin(Sn),strontium(Sr),titanium(Ti),thallium(Tl),vanadium(V),and zinc(Zn)were quantified utilizing a PerkinElmer 2000 inductively coupled plasma mass spectrometer.Principal component analysis was performed utilizing SPSS 25.0 to identify the distinctive characteristic elements of A.membranaceus.Additionally,systematic cluster analysis was conducted using these characteristic elements as variables to investigate the relationship between the primary inorganic elements and the geographical origin of A.membranaceus.[Results]17 inorganic elements were identified in A.membranaceus specimens collected from Gansu Province,with characteristic elements including Ba,Co,Fe,Ga,Mn,Zn,and Sn.The contents of inorganic elements in various sources of A.membranaceus exhibited significant variability and demonstrated distinct clustering characteristics.[Conclusions]A.membranaceus,originating from Gansu Province,exhibits a high content of inorganic elements.However,variations in ecological environments can lead to differences in the specific inorganic elements that are enriched.This study aims to provide a reference for the further development and application of A.membranaceus.展开更多
Traditional Chinese medicine(TCM)has played a significant role in the prevention and treatment of chronic heart failure(CHF).To study TCM diagnosis of CHF,a total of 278 Chinese clinical research articles on the study...Traditional Chinese medicine(TCM)has played a significant role in the prevention and treatment of chronic heart failure(CHF).To study TCM diagnosis of CHF,a total of 278 Chinese clinical research articles on the study of CHF syndromes in recent 40 years retrieved from Web of Science,Scopus,Pub Med,Embase,CNKI,Wanfang Data,Cq VIP,and Sino Med.According to cumulative frequency analysis,network analysis,and hierarchical cluster analysis,the study found the distribution of CHF syndromes was syndrome of qi deficiency with blood stasis,syndrome of qi and yin deficiency,syndrome of yang deficiency with water flooding,syndrome of heart blood stasis obstruction,syndrome of turbid phlegm,and syndrome of collapse due to primordial yang deficiency.The syndrome elements on location of illness were heart,kidney,lung,and spleen.The syndrome elements on nature of illness were qi deficiency,blood stasis,yang deficiency,yin deficiency,water retention,and turbid phlegm.These findings can provide reference to the research on diagnosis and treatment of CHF,and contribute to the study on syndrome standardization and objective research of TCM diagnosis.展开更多
To effectively address the challenge where the speed of tunnel lining construction struggles to match that of tunnel face and inverted arch construction,and to enhance the quality of secondary lining,a new type of ske...To effectively address the challenge where the speed of tunnel lining construction struggles to match that of tunnel face and inverted arch construction,and to enhance the quality of secondary lining,a new type of skeleton-free,traversing secondary lining trolley has been developed.This trolley features a set of gantries paired with two sets of formwork.The formwork adopts a multi-segment hinged and strengthened design,ensuring its own strength can meet the requirements of secondary lining concrete pouring without relying on the support of the gantries.When retracted,the formwork can be transported by the gantries through another set of formwork in the supporting state,enabling early formwork support,effectively accelerating the construction progress of the tunnel’s secondary lining,and extending the maintenance time of the secondary lining with the formwork.Finite element software modeling was used for simulation calculations,and the results indicate that the structural strength,stiffness,and other performance parameters of the new secondary lining trolley meet the design requirements,verifying the rationality of the design.展开更多
Due to their superior properties, the interest in nanostructures is increasing today in engineering. This study presents a new two-noded curved finite element for analyzing the in-plane static behaviors of curved nano...Due to their superior properties, the interest in nanostructures is increasing today in engineering. This study presents a new two-noded curved finite element for analyzing the in-plane static behaviors of curved nanobeams. Opposite to traditional curved finite elements developed by using approximate interpolation functions, the proposed curved finite element is developed by using exact analytical solutions. Although this approach was first introduced for analyzing the mechanical behaviors of macro-scale curved beams by adopting the local theory of elasticity, the exact analytical expressions used in this study were obtained from the solutions of governing equations that were expressed via the differential form of the nonlocal theory of elasticity. Therefore, the effects of shear strain and axial extension included in the analytical formulation are also inherited by the curved finite element developed here. The rigidity matrix and the consistent force vector are developed for a circular finite element. To demonstrate the applicability of the method, static analyses of various curved nanobeams subjected to different boundary conditions and loading scenarios are performed, and the obtained results are compared with the exact analytical ones. The presented study provides an accurate and low computational cost method for researchers to investigate the in-plane static behavior of curved nanobeams.展开更多
Identifying the damage and fracture properties of nuclear graphite materials and accurately simulating them are crucial when designing graphite core structures.To simulate the damage evolution and crack propagation of...Identifying the damage and fracture properties of nuclear graphite materials and accurately simulating them are crucial when designing graphite core structures.To simulate the damage evolution and crack propagation of graphite under stress in a finite element model,compression tests on disks and three-point bending tests on center-notched beams for fine-grained graphite(CDI-1D and IG11 graphite)were conducted.During these tests,digital image correlation and electronic speckle pattern interferometry techniques were utilized to observe the surface full-field displacements of the specimens.A segmented finite element inverse analysis method was developed to characterize the graphite’s damage evolution by quantifying the reduction in Young’s modulus with tensile and compressive strains in disk specimens.The fracture energy and bilinear tensile softening curve of the graphite were determined by comparing the load–displacement responses of the three-point bending tests and the finite element simulation.Finally,by combining the identified damage laws with a fracture criterion based on fracture energy,a damage–fracture model was established and used to simulate tensile tests on L-shaped specimens with different fillet radii.Simulations indicate that the damage area at the fillet expands with increasing radius,creating a blunting effect that enhances the load-bearing capacity of the specimens.This damage–fracture model can be applied to simulate graphite components in core structures.展开更多
Total hip arthroplasty for adults with sequelae from childhood hip disorders poses significant challenges due to altered anatomy.The paper published by Oommen et al reviews the essential management strategies for thes...Total hip arthroplasty for adults with sequelae from childhood hip disorders poses significant challenges due to altered anatomy.The paper published by Oommen et al reviews the essential management strategies for these complex cases.This article explores the integration of finite element analysis(FEA)to enhance surgical precision and outcomes.FEA provides detailed biomechanical insights,aiding in preoperative planning,implant design,and surgical technique optimization.By simulating implant configurations and assessing bone quality,FEA helps in customizing implants and evaluating surgical techniques like subtrochanteric shortening osteotomy.Advanced imaging techniques,such as 3D printing,virtual reality,and augmented reality,further enhance total hip arthroplasty precision.Future research should focus on validating FEA models,developing patient-specific simulations,and promoting multidisciplinary collaboration.Integrating FEA and advanced technologies in total hip arthroplasty can improve functional outcomes,reduce complications,and enhance quality of life for patients with childhood hip disorder sequelae.展开更多
The increasing occurrence of sinkholes caused by water main bursts has attracted significant research attention in recent years.This study addresses the gap in evaluating soil blowout stability resulting from water ma...The increasing occurrence of sinkholes caused by water main bursts has attracted significant research attention in recent years.This study addresses the gap in evaluating soil blowout stability resulting from water main failures by investigating the three-dimensional stability of blowouts with circular,hemispherical,and spherical openings.Advanced finite element limit analysis(FELA)combined with adaptive meshing is employed to analyze critical factors,including soil cover depth,surcharge pressure,and internal water pressure,that contribute to blowout failure.In addition,dimensionless ratios are used throughout the paper to assess the influence of these factors.Numerical findings are rigorously validated,ensuring reliability and accuracy.Practical design charts are provided to accommodate a wide range of design scenarios,offering valuable guidance for engineers.This study introduces a pioneering sinkhole simulation methodology,leading to the understanding of three-dimensional blowout stability mechanisms.展开更多
Purpose–Type-120 relief valves are critical components of locomotive braking systems,and they rapidly discharge the air pressure during brake release to enable swift pressure relief.In order to develop type-120 relie...Purpose–Type-120 relief valves are critical components of locomotive braking systems,and they rapidly discharge the air pressure during brake release to enable swift pressure relief.In order to develop type-120 relief valve rubber diaphragms with long life and high performance,the damaged faulty samples were analyzed and studied.Design/methodology/approach–Finite element analysis(FEA)was used to investigate the stress distribution and failure mechanism of the rubber diaphragms within the type-120 relief valves under dynamic loading conditions.The Ogden hyperelastic constitutive model was used to fit the diaphragm data obtained from the uniaxial tensile tests,and its suitability for the modeling of large deformations was confirmed.Findings–The FEA results indicated that,when the rubber diaphragms reached their maximum deformation,the peak stress on their upper surfaces was 5.44 MPa.Thus,this region is highly susceptible to fatigue damage.The service life of the rubber diaphragms could be extended by using rubber compounds with high tensile moduli or a fabric-reinforced rubber diaphragm.Originality/value–This study provides valuable data and experience for the development of the rubber diaphragms in the type-120 valves and other long-life rubber products in the railway field.展开更多
Purpose–This paper aims to offer a novel viewpoint for improving performance and reliability by developing and optimizing suspension components in a Y25 bogie through material optimization based on wheel–rail intera...Purpose–This paper aims to offer a novel viewpoint for improving performance and reliability by developing and optimizing suspension components in a Y25 bogie through material optimization based on wheel–rail interactions under variable load and track conditions.Design/methodology/approach–The suspension system,a critical component ensuring adaptation to road and load conditions in all vehicle types,is especially vital in heavy freight and passenger trains.In this context,the suspension set of the Y25 bogie–commonly used in T€urkiye and Europe–was modelled using CATIAV5,and stress analyses have been performed by way of ANSYS using the finite element analysis(FEA)method.E300-520-M cast steel was selected for the bogie frame,while two different spring steels,61SiCr7 and 51CrV4,were considered for the suspension springs.The modeled system was subjected to numerical analysis under loading conditions.The resulting stresses and displacements were compared with the mechanical properties of the selected materials to validate the design.Findings–The results demonstrate that the mechanical strength and deformation characteristics of the suspension components vary according to the applied external loads.The stress and displacement responses of the system were found to be within the allowable limits of the selected materials,confirming the structural integrity and reliability of the design.The suspension set is deemed suitable for the prescribed material and environmental conditions,suggesting potential for practical application in real-world rail systems.Originality/value–This research contributes to the design and optimization of bogie suspension systems using advanced CAD/CAE tools.It thinks that the material selection and numerical validation approach presented here can guide future designs in heavy load rail applications and potentially improve both safety and performance.展开更多
The incorporation of graphene fillers into polymer matrices has been recognized for its potential to enhance thermal conductivity,which is particularly beneficial for applications in thermal management.The uniformity ...The incorporation of graphene fillers into polymer matrices has been recognized for its potential to enhance thermal conductivity,which is particularly beneficial for applications in thermal management.The uniformity of graphene dispersion is pivotal to achieving optimal thermal conductivity,thereby directly influencing the effectiveness of thermal management,including the mitigation of local hot-spot temperatures.This research employs a quantitative approach to assess the distribution of graphene fillers within a PBX(plastic-bonded explosive)matrix,focusing specifically on the thermal management of hot spots.Through finite element method(FEM)simulations,we have explored the impact of graphene filler orientation,proximity to the central heat source,and spatial clustering on heat transfer.Our findings indicate that the strategic distribution of graphene fillers can create efficient thermal conduction channels,which significantly reduce the temperatures at local hot spots.In a model containing 0.336%graphene by volume,the central hot-spot temperature was reduced by approximately 60 K compared to a pure PBX material,under a heat flux of 600 W/m^(2).This study offers valuable insights into the optimization of the spatial arrangement of low-concentration graphene fillers,aiming to improve the thermal management capabilities of HMX-based PBX explosives.展开更多
Microstructure topology evolution during severe plastic deformation(SPD)is crucial for understanding and optimising the mechanical properties of metallic materials,though its prediction remains challenging.Herein,we c...Microstructure topology evolution during severe plastic deformation(SPD)is crucial for understanding and optimising the mechanical properties of metallic materials,though its prediction remains challenging.Herein,we combine discrete cell complexes(DCC),a fully discrete algebraic topology model-with finite element analysis(FEA)to simulate and analyse the microstructure topology of pure copper under SPD.Using DCC,we model the evolution of microstructure topology characterised by Betti numbers(β_(0),β_(1),β_(2))and Euler characteristic(χ).This captures key changes in GBNs and topological features within representative volume elements(RVEs)containing several hundred grains during SPD-induced recrystallisation.As SPD cycles increase,high-angle grain boundaries(HAGBs)progressively form.Topological analysis reveals an overall decrease in β_(0)values,indicating fewer isolated HAGB substructures,while β_(2) values show a steady upward trend,highlighting new grain formation.Leveraging DCC-derived RVE topology and FEA-generated plastic strain data,we directly simulate the evolution and spatial distribution of microstructure topology and HAGB fraction in a copper tube undergoing cyclic parallel tube channel angular pressing(PTCAP),a representative SPD technique.Within the tube,the HAGB fraction continuously increases with PTCAP cycles,reflecting the microstructure’s gradual transition from subgrains to fully-formed grains.Analysis of Betti number distribution and evolution reveals the microstructural reconstruction mechanism underpinning this subgrain to grain transition during PTCAP.We further demonstrate the significant influence of spatially non-uniform plastic strain distribution on microstructure reconstruction kinetics.This study demonstrates a feasible approach for simulating microstructure topology evolution of metals processed by cyclic SPD via the integration of DCC and FEA.展开更多
Serving as the initiating explosive devices between the propellant tank and the engines,metal-based rupture diaphragms are widely used in ramjet igniters owing to the advantages provided by their simple structure,smal...Serving as the initiating explosive devices between the propellant tank and the engines,metal-based rupture diaphragms are widely used in ramjet igniters owing to the advantages provided by their simple structure,small size,and low cost.However,the reliability of rupture pressure directly affects the success of engine ignition and rocket launch,which is mainly influenced by factors like material,structure,and residual thickness of the surface notch of the diaphragm.Among those,the geometry of the notch is easy to define and control when compared to the mechanical parameters of the ruptured diaphragm.Thus,to make the diaphragm rupture(1A30 Al)within the required pressure range(0.4 MPa±3.5%)with highly sensitive and reliability,we draw inspiration from the arthropod’s force-sensitive slit organ which encompasses curved microgrooves to design a Ω-shaped notch for the rupture diaphragm.Finite element analysis is used to study the relationship between the burst pressure and geometric dimension of theΩ-shaped and bioinspired microgroove.Based on that,metal-based rupture diaphragms are fabricated by femtosecond laser processing technology,followed by rupture tests.Experiment results demonstrate that the practical rupture pressure of the diaphragm is highly consistent with the finite element analysis results,which verifies the effectiveness of the bionic design.展开更多
A new quadrilateral finite element IQ4 is developed for the free vibration of carbon nanotube-reinforced composite(CNTRC)perforated plates with a central cutout.By enriching the membrane part and incorporating a proje...A new quadrilateral finite element IQ4 is developed for the free vibration of carbon nanotube-reinforced composite(CNTRC)perforated plates with a central cutout.By enriching the membrane part and incorporating a projected shear technique,the IQ4 element is proposed to address the known limitations of the standard Q4 element,such as shear locking and limited consistency in the coupling ofmembrane-bending components.The proposed element is formulated within the FSDT-based framework and assessed through benchmark tests to verify its convergence and accuracy.The governing equations are obtained via theweak formofHamilton’s principle.Particular attention is given to the influence of carbon nanotube volume fraction,distribution patterns,and boundary conditions on the fundamental frequency response of CNTRC plates with cutouts.In addition,a parametric study is conducted to assess the influence of cutout geometric configuration,shape,and size ratios on the vibrational response of the CNTRC plate.The numerical results demonstrate that the formulated IQ4 element provides stable and accurate estimations of natural frequencies,even in the presence of a cutout and the coupled effects of the non-uniform distribution of reinforcement through the plate thickness.The developed formulation is expected to contribute to the structural design and optimization of advanced lightweight systems,particularly in aerospace and mechanical engineering applications.展开更多
This article presents a micro-structure tensor enhanced elasto-plastic finite element(FE)method to address strength anisotropy in three-dimensional(3D)soil slope stability analysis.The gravity increase method(GIM)is e...This article presents a micro-structure tensor enhanced elasto-plastic finite element(FE)method to address strength anisotropy in three-dimensional(3D)soil slope stability analysis.The gravity increase method(GIM)is employed to analyze the stability of 3D anisotropic soil slopes.The accuracy of the proposed method is first verified against the data in the literature.We then simulate the 3D soil slope with a straight slope surface and the convex and concave slope surfaces with a 90turning corner to study the 3D effect on slope stability and the failure mechanism under anisotropy conditions.Based on our numerical results,the end effect significantly impacts the failure mechanism and safety factor.Anisotropy degree notably affects the safety factor,with higher degrees leading to deeper landslides.For concave slopes,they can be approximated by straight slopes with suitable boundary conditions to assess their stability.Furthermore,a case study of the Saint-Alban test embankment A in Quebec,Canada,is provided to demonstrate the applicability of the proposed FE model.展开更多
In order to analyze the load carrying capacity of prestressed concrete box girders, failure behaviors of in-situ deteriorated continuous prestressed concrete box girders under loading are experimentally observed and a...In order to analyze the load carrying capacity of prestressed concrete box girders, failure behaviors of in-situ deteriorated continuous prestressed concrete box girders under loading are experimentally observed and a finite failure analysis method for predicting behaviors of box girders is developed. A degenerated solid shell element is used to simulate box girders and material nonlinearity is considered. Since pre-stressed concrete box girders usually have a large number of curve prestressed tendons, a type of combined element is presented to simulate the prestressed tendons of box girders, and then the number of elements can be significantly reduced. The analytical results are compared with full-scale failure test results. The comparison shows that the presented method can be effectively applied to the failure analysis of in-situ continuous prestressed concrete box girders, and it also shows that the studied old bridge still has enough load carrying capacity.展开更多
The effect of structure,elastic modulus and thickness of lower modulus layer in porous titanium implants on the stress distribution at the implant-bone interface was investigated.Three-dimensional finite element model...The effect of structure,elastic modulus and thickness of lower modulus layer in porous titanium implants on the stress distribution at the implant-bone interface was investigated.Three-dimensional finite element models of different titanium implants were constructed.The structures of the implants included the whole lower modulus style （No.1）,bio-mimetic style （No.2）,the whole lower modulus style in cancellous bone （No.3） and the whole dense style No.4.The stress distributions at bone-implant interface under static loading were analyzed using Ansys Workbench 10.0 software.The results indicated that the distribution of interface stress is strongly depended on the structure of the implants.The maximum stresses in cancellous bone and root region of implant No.2 are lower than those in the other three implants.A decrease in the modulus of the low modulus layer facilitates the interface stress transferring.Increasing the thickness of the low modulus layer can reduce the stress and induce a more uniform stress distribution at the interface.Among the four implants,biomimetic style implant No.2 is superior in transferring implant-bone interface stress to surrounding bones.展开更多
To analyze the stress state of steel orthotropic deck pavement and provide reference for the design of the overlay, the inner stress state and strain distribution of surfacing under the load of the deformation of the ...To analyze the stress state of steel orthotropic deck pavement and provide reference for the design of the overlay, the inner stress state and strain distribution of surfacing under the load of the deformation of the whole bridge structure and tyre load are analyzed by the finite element method of submodeling. Influence of surfacing modulus on the strain state of the overlay is analyzed for the purpose of the optimal design of the overlay structure. Analysis results show that the deformation of the whole bridge structure has no evident influence on the stress state of the overlay. The key factor of the overlay design is the transverse tensile strain in the overlay above the upper edge of web plate of rib. The stress state of the overlay is influenced evidently by the modulus of rigidity transform overlay. And the stress state of the overlay can be optimized and lowered by increasing the modulus and thickness of rigidity transform overlay, The fatigue test has been done to evaluate the fatigue performance and modulus of different deck pavement materials such as epoxy asphalt, SBS modified asphalt, rosphalt asphalt which can provide reference for deck pavement structure design.展开更多
基金supported by the Science and Technology Research and Development Plan of the China State Railway Group Company Limited(No.Q2023J012).
文摘Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.
文摘Design a precision electroplating mechanical structure for automobiles based on finite element analysis method and analyze its mechanical properties.Taking the automobile steering knuckle as the research object,ABAQUS parametric modeling technology is used to construct its three-dimensional geometric model,and geometric simplification is carried out.Two surface treatment processes,HK-35 zinc nickel alloy electroplating and pure zinc electroplating,were designed,and the influence of different coatings on the mechanical properties of steering knuckles was compared and analyzed through numerical simulation.At the same time,standard specimens were prepared for salt spray corrosion testing and scratch method combined strength testing to verify the numerical simulation results.The results showed that under emergency braking and composite working conditions,the peak Von Mises stress of the zinc nickel alloy coating was 119.85 MPa,which was lower than that of the pure zinc coating and the alkaline electroplated zinc layer.Its equivalent strain value was 652×10^(-6),which was lower than that of the pure zinc coating and the alkaline electroplated zinc layer.Experimental data confirms that zinc nickel alloy coatings exhibit significant advantages in stress distribution uniformity,strain performance,and load-bearing capacity in high stress zones.The salt spray corrosion test further indicates that the coating has superior corrosion resistance and coating substrate interface bonding strength,which can significantly improve the mechanical stability and long-term reliability of automotive precision electroplating mechanical structures.
文摘Objective: To compare the stress distribution in the periodontal ligament under different orthodontic forces during canine distalization using long-arm brackets, and to determine the optimal force value for this device in orthodontic treatment. Methods: A finite element model was constructed after extracting the mandibular first premolar, and a long-arm bracket with a traction height of 6 mm was placed on the labial side of the mandibular canine. Three working conditions of 50 g, 100 g, and 150 g were simulated, and the magnitude and distribution of von Mises stress in the periodontal ligament were compared for each condition. Results: The maximum von Mises stress in the periodontal ligament was 0.013281 MPa in the 50 g condition, 0.02536 MPa in the 100 g condition, and 0.035549 MPa in the 150 g condition. As the orthodontic force increased, the stress distribution area in the periodontal ligament also expanded. Conclusion: A 100 g orthodontic force is the most suitable when using long-arm brackets, providing a relatively uniform stress distribution in the periodontal ligament and keeping the stress within a reasonable range.
基金Supported by Project of NMPA Key Laboratory for Quality Control of Traditional Chinese Medicine(2023GSMPA-KL06,2024GSMPA-KL16).
文摘[Objectives]To investigate the content and distribution of inorganic elements in Astragalus membranaceus sourced from various regions in Gansu Province.[Methods]28 batches of A.membranaceus samples were collected and subsequently digested using the Multiwave 7000 super microwave digestion system.The contents of aluminum(Al),barium(Ba),beryllium(Be),cobalt(Co),chromium(Cr),iron(Fe),gallium(Ga),magnesium(Mg),manganese(Mn),nickel(Ni),antimony(Sb),tin(Sn),strontium(Sr),titanium(Ti),thallium(Tl),vanadium(V),and zinc(Zn)were quantified utilizing a PerkinElmer 2000 inductively coupled plasma mass spectrometer.Principal component analysis was performed utilizing SPSS 25.0 to identify the distinctive characteristic elements of A.membranaceus.Additionally,systematic cluster analysis was conducted using these characteristic elements as variables to investigate the relationship between the primary inorganic elements and the geographical origin of A.membranaceus.[Results]17 inorganic elements were identified in A.membranaceus specimens collected from Gansu Province,with characteristic elements including Ba,Co,Fe,Ga,Mn,Zn,and Sn.The contents of inorganic elements in various sources of A.membranaceus exhibited significant variability and demonstrated distinct clustering characteristics.[Conclusions]A.membranaceus,originating from Gansu Province,exhibits a high content of inorganic elements.However,variations in ecological environments can lead to differences in the specific inorganic elements that are enriched.This study aims to provide a reference for the further development and application of A.membranaceus.
基金financed by the grants from the National Natural Science Foundation of China(No.81803996)Shanghai Key Laboratory of Health Identification and Assessment(No.21DZ2271000)。
文摘Traditional Chinese medicine(TCM)has played a significant role in the prevention and treatment of chronic heart failure(CHF).To study TCM diagnosis of CHF,a total of 278 Chinese clinical research articles on the study of CHF syndromes in recent 40 years retrieved from Web of Science,Scopus,Pub Med,Embase,CNKI,Wanfang Data,Cq VIP,and Sino Med.According to cumulative frequency analysis,network analysis,and hierarchical cluster analysis,the study found the distribution of CHF syndromes was syndrome of qi deficiency with blood stasis,syndrome of qi and yin deficiency,syndrome of yang deficiency with water flooding,syndrome of heart blood stasis obstruction,syndrome of turbid phlegm,and syndrome of collapse due to primordial yang deficiency.The syndrome elements on location of illness were heart,kidney,lung,and spleen.The syndrome elements on nature of illness were qi deficiency,blood stasis,yang deficiency,yin deficiency,water retention,and turbid phlegm.These findings can provide reference to the research on diagnosis and treatment of CHF,and contribute to the study on syndrome standardization and objective research of TCM diagnosis.
文摘To effectively address the challenge where the speed of tunnel lining construction struggles to match that of tunnel face and inverted arch construction,and to enhance the quality of secondary lining,a new type of skeleton-free,traversing secondary lining trolley has been developed.This trolley features a set of gantries paired with two sets of formwork.The formwork adopts a multi-segment hinged and strengthened design,ensuring its own strength can meet the requirements of secondary lining concrete pouring without relying on the support of the gantries.When retracted,the formwork can be transported by the gantries through another set of formwork in the supporting state,enabling early formwork support,effectively accelerating the construction progress of the tunnel’s secondary lining,and extending the maintenance time of the secondary lining with the formwork.Finite element software modeling was used for simulation calculations,and the results indicate that the structural strength,stiffness,and other performance parameters of the new secondary lining trolley meet the design requirements,verifying the rationality of the design.
基金supported by Scientific Research Projects Department of Istanbul Technical University.Project Number:MGA-2018-41546.Grant receiver:E.T.
文摘Due to their superior properties, the interest in nanostructures is increasing today in engineering. This study presents a new two-noded curved finite element for analyzing the in-plane static behaviors of curved nanobeams. Opposite to traditional curved finite elements developed by using approximate interpolation functions, the proposed curved finite element is developed by using exact analytical solutions. Although this approach was first introduced for analyzing the mechanical behaviors of macro-scale curved beams by adopting the local theory of elasticity, the exact analytical expressions used in this study were obtained from the solutions of governing equations that were expressed via the differential form of the nonlocal theory of elasticity. Therefore, the effects of shear strain and axial extension included in the analytical formulation are also inherited by the curved finite element developed here. The rigidity matrix and the consistent force vector are developed for a circular finite element. To demonstrate the applicability of the method, static analyses of various curved nanobeams subjected to different boundary conditions and loading scenarios are performed, and the obtained results are compared with the exact analytical ones. The presented study provides an accurate and low computational cost method for researchers to investigate the in-plane static behavior of curved nanobeams.
基金supported by the National Natural Science Foundation of China(No.52278251)Guizhou Provincial Sciences and Technology Projects(ZK[2022]Key 007).
文摘Identifying the damage and fracture properties of nuclear graphite materials and accurately simulating them are crucial when designing graphite core structures.To simulate the damage evolution and crack propagation of graphite under stress in a finite element model,compression tests on disks and three-point bending tests on center-notched beams for fine-grained graphite(CDI-1D and IG11 graphite)were conducted.During these tests,digital image correlation and electronic speckle pattern interferometry techniques were utilized to observe the surface full-field displacements of the specimens.A segmented finite element inverse analysis method was developed to characterize the graphite’s damage evolution by quantifying the reduction in Young’s modulus with tensile and compressive strains in disk specimens.The fracture energy and bilinear tensile softening curve of the graphite were determined by comparing the load–displacement responses of the three-point bending tests and the finite element simulation.Finally,by combining the identified damage laws with a fracture criterion based on fracture energy,a damage–fracture model was established and used to simulate tensile tests on L-shaped specimens with different fillet radii.Simulations indicate that the damage area at the fillet expands with increasing radius,creating a blunting effect that enhances the load-bearing capacity of the specimens.This damage–fracture model can be applied to simulate graphite components in core structures.
文摘Total hip arthroplasty for adults with sequelae from childhood hip disorders poses significant challenges due to altered anatomy.The paper published by Oommen et al reviews the essential management strategies for these complex cases.This article explores the integration of finite element analysis(FEA)to enhance surgical precision and outcomes.FEA provides detailed biomechanical insights,aiding in preoperative planning,implant design,and surgical technique optimization.By simulating implant configurations and assessing bone quality,FEA helps in customizing implants and evaluating surgical techniques like subtrochanteric shortening osteotomy.Advanced imaging techniques,such as 3D printing,virtual reality,and augmented reality,further enhance total hip arthroplasty precision.Future research should focus on validating FEA models,developing patient-specific simulations,and promoting multidisciplinary collaboration.Integrating FEA and advanced technologies in total hip arthroplasty can improve functional outcomes,reduce complications,and enhance quality of life for patients with childhood hip disorder sequelae.
文摘The increasing occurrence of sinkholes caused by water main bursts has attracted significant research attention in recent years.This study addresses the gap in evaluating soil blowout stability resulting from water main failures by investigating the three-dimensional stability of blowouts with circular,hemispherical,and spherical openings.Advanced finite element limit analysis(FELA)combined with adaptive meshing is employed to analyze critical factors,including soil cover depth,surcharge pressure,and internal water pressure,that contribute to blowout failure.In addition,dimensionless ratios are used throughout the paper to assess the influence of these factors.Numerical findings are rigorously validated,ensuring reliability and accuracy.Practical design charts are provided to accommodate a wide range of design scenarios,offering valuable guidance for engineers.This study introduces a pioneering sinkhole simulation methodology,leading to the understanding of three-dimensional blowout stability mechanisms.
基金supported by the Science and Technology Research and Development Plan of the China State Railway Group Company Limited(Grant No.N2023J053).
文摘Purpose–Type-120 relief valves are critical components of locomotive braking systems,and they rapidly discharge the air pressure during brake release to enable swift pressure relief.In order to develop type-120 relief valve rubber diaphragms with long life and high performance,the damaged faulty samples were analyzed and studied.Design/methodology/approach–Finite element analysis(FEA)was used to investigate the stress distribution and failure mechanism of the rubber diaphragms within the type-120 relief valves under dynamic loading conditions.The Ogden hyperelastic constitutive model was used to fit the diaphragm data obtained from the uniaxial tensile tests,and its suitability for the modeling of large deformations was confirmed.Findings–The FEA results indicated that,when the rubber diaphragms reached their maximum deformation,the peak stress on their upper surfaces was 5.44 MPa.Thus,this region is highly susceptible to fatigue damage.The service life of the rubber diaphragms could be extended by using rubber compounds with high tensile moduli or a fabric-reinforced rubber diaphragm.Originality/value–This study provides valuable data and experience for the development of the rubber diaphragms in the type-120 valves and other long-life rubber products in the railway field.
文摘Purpose–This paper aims to offer a novel viewpoint for improving performance and reliability by developing and optimizing suspension components in a Y25 bogie through material optimization based on wheel–rail interactions under variable load and track conditions.Design/methodology/approach–The suspension system,a critical component ensuring adaptation to road and load conditions in all vehicle types,is especially vital in heavy freight and passenger trains.In this context,the suspension set of the Y25 bogie–commonly used in T€urkiye and Europe–was modelled using CATIAV5,and stress analyses have been performed by way of ANSYS using the finite element analysis(FEA)method.E300-520-M cast steel was selected for the bogie frame,while two different spring steels,61SiCr7 and 51CrV4,were considered for the suspension springs.The modeled system was subjected to numerical analysis under loading conditions.The resulting stresses and displacements were compared with the mechanical properties of the selected materials to validate the design.Findings–The results demonstrate that the mechanical strength and deformation characteristics of the suspension components vary according to the applied external loads.The stress and displacement responses of the system were found to be within the allowable limits of the selected materials,confirming the structural integrity and reliability of the design.The suspension set is deemed suitable for the prescribed material and environmental conditions,suggesting potential for practical application in real-world rail systems.Originality/value–This research contributes to the design and optimization of bogie suspension systems using advanced CAD/CAE tools.It thinks that the material selection and numerical validation approach presented here can guide future designs in heavy load rail applications and potentially improve both safety and performance.
基金supported by the National Natural Science Foundation of China(Grant No.U2330208).
文摘The incorporation of graphene fillers into polymer matrices has been recognized for its potential to enhance thermal conductivity,which is particularly beneficial for applications in thermal management.The uniformity of graphene dispersion is pivotal to achieving optimal thermal conductivity,thereby directly influencing the effectiveness of thermal management,including the mitigation of local hot-spot temperatures.This research employs a quantitative approach to assess the distribution of graphene fillers within a PBX(plastic-bonded explosive)matrix,focusing specifically on the thermal management of hot spots.Through finite element method(FEM)simulations,we have explored the impact of graphene filler orientation,proximity to the central heat source,and spatial clustering on heat transfer.Our findings indicate that the strategic distribution of graphene fillers can create efficient thermal conduction channels,which significantly reduce the temperatures at local hot spots.In a model containing 0.336%graphene by volume,the central hot-spot temperature was reduced by approximately 60 K compared to a pure PBX material,under a heat flux of 600 W/m^(2).This study offers valuable insights into the optimization of the spatial arrangement of low-concentration graphene fillers,aiming to improve the thermal management capabilities of HMX-based PBX explosives.
基金support from Outstanding Youth Fund of Jiangsu Province(BK20240077)Key Project(Provincial-Municipal Joint)of Jiangsu Province(BK20243044)+2 种基金Fundamental Research Funds for the Central Universities(NE2024001)National Youth Talents Programof Chinaa project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Microstructure topology evolution during severe plastic deformation(SPD)is crucial for understanding and optimising the mechanical properties of metallic materials,though its prediction remains challenging.Herein,we combine discrete cell complexes(DCC),a fully discrete algebraic topology model-with finite element analysis(FEA)to simulate and analyse the microstructure topology of pure copper under SPD.Using DCC,we model the evolution of microstructure topology characterised by Betti numbers(β_(0),β_(1),β_(2))and Euler characteristic(χ).This captures key changes in GBNs and topological features within representative volume elements(RVEs)containing several hundred grains during SPD-induced recrystallisation.As SPD cycles increase,high-angle grain boundaries(HAGBs)progressively form.Topological analysis reveals an overall decrease in β_(0)values,indicating fewer isolated HAGB substructures,while β_(2) values show a steady upward trend,highlighting new grain formation.Leveraging DCC-derived RVE topology and FEA-generated plastic strain data,we directly simulate the evolution and spatial distribution of microstructure topology and HAGB fraction in a copper tube undergoing cyclic parallel tube channel angular pressing(PTCAP),a representative SPD technique.Within the tube,the HAGB fraction continuously increases with PTCAP cycles,reflecting the microstructure’s gradual transition from subgrains to fully-formed grains.Analysis of Betti number distribution and evolution reveals the microstructural reconstruction mechanism underpinning this subgrain to grain transition during PTCAP.We further demonstrate the significant influence of spatially non-uniform plastic strain distribution on microstructure reconstruction kinetics.This study demonstrates a feasible approach for simulating microstructure topology evolution of metals processed by cyclic SPD via the integration of DCC and FEA.
基金supported by the National Key R&D Program of China(Grant No.2022YFB4601700).
文摘Serving as the initiating explosive devices between the propellant tank and the engines,metal-based rupture diaphragms are widely used in ramjet igniters owing to the advantages provided by their simple structure,small size,and low cost.However,the reliability of rupture pressure directly affects the success of engine ignition and rocket launch,which is mainly influenced by factors like material,structure,and residual thickness of the surface notch of the diaphragm.Among those,the geometry of the notch is easy to define and control when compared to the mechanical parameters of the ruptured diaphragm.Thus,to make the diaphragm rupture(1A30 Al)within the required pressure range(0.4 MPa±3.5%)with highly sensitive and reliability,we draw inspiration from the arthropod’s force-sensitive slit organ which encompasses curved microgrooves to design a Ω-shaped notch for the rupture diaphragm.Finite element analysis is used to study the relationship between the burst pressure and geometric dimension of theΩ-shaped and bioinspired microgroove.Based on that,metal-based rupture diaphragms are fabricated by femtosecond laser processing technology,followed by rupture tests.Experiment results demonstrate that the practical rupture pressure of the diaphragm is highly consistent with the finite element analysis results,which verifies the effectiveness of the bionic design.
文摘A new quadrilateral finite element IQ4 is developed for the free vibration of carbon nanotube-reinforced composite(CNTRC)perforated plates with a central cutout.By enriching the membrane part and incorporating a projected shear technique,the IQ4 element is proposed to address the known limitations of the standard Q4 element,such as shear locking and limited consistency in the coupling ofmembrane-bending components.The proposed element is formulated within the FSDT-based framework and assessed through benchmark tests to verify its convergence and accuracy.The governing equations are obtained via theweak formofHamilton’s principle.Particular attention is given to the influence of carbon nanotube volume fraction,distribution patterns,and boundary conditions on the fundamental frequency response of CNTRC plates with cutouts.In addition,a parametric study is conducted to assess the influence of cutout geometric configuration,shape,and size ratios on the vibrational response of the CNTRC plate.The numerical results demonstrate that the formulated IQ4 element provides stable and accurate estimations of natural frequencies,even in the presence of a cutout and the coupled effects of the non-uniform distribution of reinforcement through the plate thickness.The developed formulation is expected to contribute to the structural design and optimization of advanced lightweight systems,particularly in aerospace and mechanical engineering applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.51890912,51979025 and 52011530189).
文摘This article presents a micro-structure tensor enhanced elasto-plastic finite element(FE)method to address strength anisotropy in three-dimensional(3D)soil slope stability analysis.The gravity increase method(GIM)is employed to analyze the stability of 3D anisotropic soil slopes.The accuracy of the proposed method is first verified against the data in the literature.We then simulate the 3D soil slope with a straight slope surface and the convex and concave slope surfaces with a 90turning corner to study the 3D effect on slope stability and the failure mechanism under anisotropy conditions.Based on our numerical results,the end effect significantly impacts the failure mechanism and safety factor.Anisotropy degree notably affects the safety factor,with higher degrees leading to deeper landslides.For concave slopes,they can be approximated by straight slopes with suitable boundary conditions to assess their stability.Furthermore,a case study of the Saint-Alban test embankment A in Quebec,Canada,is provided to demonstrate the applicability of the proposed FE model.
基金Post-Doctoral Innovative Projects of Shandong Province(No.200703072)the National Natural Science Foundation of China(No.50574053)
文摘In order to analyze the load carrying capacity of prestressed concrete box girders, failure behaviors of in-situ deteriorated continuous prestressed concrete box girders under loading are experimentally observed and a finite failure analysis method for predicting behaviors of box girders is developed. A degenerated solid shell element is used to simulate box girders and material nonlinearity is considered. Since pre-stressed concrete box girders usually have a large number of curve prestressed tendons, a type of combined element is presented to simulate the prestressed tendons of box girders, and then the number of elements can be significantly reduced. The analytical results are compared with full-scale failure test results. The comparison shows that the presented method can be effectively applied to the failure analysis of in-situ continuous prestressed concrete box girders, and it also shows that the studied old bridge still has enough load carrying capacity.
基金Project(30770576) supported by the National Natural Science Foundation of ChinaProject(2007AA03Z114) supported by Hi-tech Research and Development Program of ChinaProject supported by State Key Laboratory of Powder Metallurgy,China
文摘The effect of structure,elastic modulus and thickness of lower modulus layer in porous titanium implants on the stress distribution at the implant-bone interface was investigated.Three-dimensional finite element models of different titanium implants were constructed.The structures of the implants included the whole lower modulus style （No.1）,bio-mimetic style （No.2）,the whole lower modulus style in cancellous bone （No.3） and the whole dense style No.4.The stress distributions at bone-implant interface under static loading were analyzed using Ansys Workbench 10.0 software.The results indicated that the distribution of interface stress is strongly depended on the structure of the implants.The maximum stresses in cancellous bone and root region of implant No.2 are lower than those in the other three implants.A decrease in the modulus of the low modulus layer facilitates the interface stress transferring.Increasing the thickness of the low modulus layer can reduce the stress and induce a more uniform stress distribution at the interface.Among the four implants,biomimetic style implant No.2 is superior in transferring implant-bone interface stress to surrounding bones.
文摘To analyze the stress state of steel orthotropic deck pavement and provide reference for the design of the overlay, the inner stress state and strain distribution of surfacing under the load of the deformation of the whole bridge structure and tyre load are analyzed by the finite element method of submodeling. Influence of surfacing modulus on the strain state of the overlay is analyzed for the purpose of the optimal design of the overlay structure. Analysis results show that the deformation of the whole bridge structure has no evident influence on the stress state of the overlay. The key factor of the overlay design is the transverse tensile strain in the overlay above the upper edge of web plate of rib. The stress state of the overlay is influenced evidently by the modulus of rigidity transform overlay. And the stress state of the overlay can be optimized and lowered by increasing the modulus and thickness of rigidity transform overlay, The fatigue test has been done to evaluate the fatigue performance and modulus of different deck pavement materials such as epoxy asphalt, SBS modified asphalt, rosphalt asphalt which can provide reference for deck pavement structure design.
