To solve the problem of abnormal abrasion of Cu-Based Friction Materials(CBFMs),Bionic Non-Smooth Surface(BNS)on friction surface of CBFMs was constructed based on bionic principles,and the optimal bionic prototype wa...To solve the problem of abnormal abrasion of Cu-Based Friction Materials(CBFMs),Bionic Non-Smooth Surface(BNS)on friction surface of CBFMs was constructed based on bionic principles,and the optimal bionic prototype was selected by Finite Element Method(FEM).In addition,the bionic parameters were optimized by Response Surface Method(RSM).Samples holding BNS were prepared by Laser Processing,tribological properties were tested by a Friction and Wear Tester and worn surface morphology was characterized by a Scanning Electron Microscope(SEM).The results showed that BNS on friction surface could regulate the stress distribution and alleviate the peak stress.Among all samples,the coupled texture of pit-hexagonal got the minimum peak stress.During braking,bionic texture could also collect wear debris or change the motion forms from sliding to rotation,which can reduce abnormal abrasion.The wear rate was reduced by 19.31%.The results in this paper can provide a new idea for enhancing the tribological properties of CBFMs,and can also lay the foundation for further research of bionic tribology.展开更多
Centrifugal pumps are extensively employed in ocean engineering,such as ship power systems,water transportation,and mineral exploitation.Pressure fluctuation suppression is essential for the operation stability and se...Centrifugal pumps are extensively employed in ocean engineering,such as ship power systems,water transportation,and mineral exploitation.Pressure fluctuation suppression is essential for the operation stability and service life of the centrifugal pump.In this paper,a new method of bionic structure is proposed for the blade surface of a centrifugal pump,which is inspired by the fish scale and comprises a leading edge,a trailing edge,and two symmetrical side edges.This fish scale structure is applied to the blade pressure and suction surfaces,and an impeller with a fish scale structure is constructed.A test rig for a centrifugal pump is developed to determine the pressure fluctuation in the pump with a prototype impeller and fish scale structure impeller.Results reveal that the dominant frequency of pressure fluctuation in volute is the blade passing frequency(f_(bpf))of 193.33 Hz,which is triggered by the interaction between the tongue and the impeller.The bionic structure of the fish scale effectively suppresses the pressure fluctuation amplitude at f_(bpf).From flow rates of 0.6 Q_(d)to 1.2 Q_(d),the average suppressions in pressure fluctuation amplitudes at f_(bpf)are 20.98%,5.85%,19.20%,and 25.77%.展开更多
Heterogeneous manufacturing is a topic that continues to receive attention.As an emerging manufacturing technology,additive manufacturing can provide strong technical support for heterogeneous manufacturing.In this st...Heterogeneous manufacturing is a topic that continues to receive attention.As an emerging manufacturing technology,additive manufacturing can provide strong technical support for heterogeneous manufacturing.In this study,both homogeneous and heterogeneous composite tubular bionic components were fabricated based on the cold metal transition technology,and the influence of deposition current on the microstructure and mechanical properties of the components was studied.The results show that the interface of the as-deposited heterogeneous composite component is well bonded,and there is an obvious mechanical interlocking structure.The compressive yield strength and elongation of the heterogeneous composite components are higher than those of the homogeneous components,and are positively correlated with the deposition current.Due to the fluctuation of element content,there are a large number of fine grain structures at the interface of the heterogeneous composite components,which increases the mechanical properties.展开更多
As a global concern,environmental protection and energy conservation have attracted significant attention.Due to the large carbon emission of electricity,promoting green and low-carbon transformation of the power indu...As a global concern,environmental protection and energy conservation have attracted significant attention.Due to the large carbon emission of electricity,promoting green and low-carbon transformation of the power industry via the synergistic development of clean energy sources is essential.Rotating machinery plays a crucial role in pumped storage,hydropower generation,and nuclear power generation.Inspired by bionics,non-smooth features of creatures in nature have been introduced into the structure design of efficient rotating machines.First,the concept and classification of bionics are described.Then,the representative applications of non-smooth surface bionic structures in rotating machineries are systematically and comprehensively reviewed,such as groove structure,pit structure,and other non-smooth surfaces.Finally,conclusions are drawn and future directions are presented.The effective design of a bionic structure contributes toward noise reduction,drag reduction and efficiency improvement of rotating machineries.Green and ecological rotating machinery will remarkably reduce energy consumption and contribute to the realization of the“double carbon”goal.展开更多
Each specific structure of organisms is the best choice under specific circumstances.The excellent characteristic structures of these organisms have great application potential in the design and multi-functional optim...Each specific structure of organisms is the best choice under specific circumstances.The excellent characteristic structures of these organisms have great application potential in the design and multi-functional optimization of energy-absorbing structures such as vehicle collisions,satellite landings,and military equipment.In this paper,using the principle of structural bionics,using the advantages of the honeycomb structure and the light weight and high strength of beetle elytra,four bionic lattice structures are studied:CH,ZPRH,SCH and IBE.Using NiTi shape memory alloy,a unique material as the base material,samples are prepared using selective laser melting(SLM)technology.By comparing the test results of the quasi-static compression test with the results of the numerical simulation,it is found that compared with the other three bionic lattice structures,the SCH structure has the best energy absorption effect in the effective stroke in the test,and the specific energy absorption can reach 6.32 J/g.ZPRH,SCH,and IBE structures not only have good and stable deformation behavior,but also have excellent impact resistance and shape memory properties.The design of these structures provides a reference for the design of anti-shock cushioning structures with self-recovery functions in the future.展开更多
A novel single-step method is proposed for the analysis of dynamic response of visco-elastic structures containing non-smooth contactable interfaces. In the method, a two-level algorithm is employed for dealing with a...A novel single-step method is proposed for the analysis of dynamic response of visco-elastic structures containing non-smooth contactable interfaces. In the method, a two-level algorithm is employed for dealing with a nonlinear boundary condition caused by the dynamic contact of interfaces. At the first level, an explicit method is adopted to calculate nodal displacements of global viscoelastic system without considering the effect of dynamic contact of interfaces and at the second level, by introducing contact conditions of interfaces, a group of equations of lower order is derived to calculate dynamic contact normal and shear forces on the interfaces. The method is convenient and efficient for the analysis of problems of dynamic contact. The accuracy of the method is of the second order and the numerical stability condition is wider than that of other explicit methods.展开更多
This study investigates the effectiveness of the non-smooth semi-active control algorithm on suppressing the vibration performance of a building structure subjected to seismic waves. According to the Lyapunov stabilit...This study investigates the effectiveness of the non-smooth semi-active control algorithm on suppressing the vibration performance of a building structure subjected to seismic waves. According to the Lyapunov stability theory, it has bene proven that the non-smooth semi-active control algorithm can achieve a finite-time stability of the vibration relative to the isolation layer of a building structure. Through numerical simulation of two buildings with different parameters subjected to the input of a seismic wave, the vibration conditions of passive control, LQR semi-active control and non-smooth semiactive control are compared and analyzed. The simulation results show that the non-smooth semi-active control algorithm has a better robustness and effectiveness in restraining the impact of earthquakes on the structure.展开更多
Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve fle...Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve flexible connector,the IPMC linear driving unit simulation model is built and the IPMC material-driving dynamic control structure of bionic gill unit is developed.Meanwhile,through the stress analysis of bionic gill plate and the motion simulation of bionic gill unit,it is verified that various dynamic control and active control of the jet orifice under the condition of different mainstream field velocities will be taken by using IPMC material-driving.Moreover,the large-deflection deformation of bionic gill plate under dynamic pressure and the comparative analysis with that of a rigid gill plate is studied,leading to the achievement of approximate revised modifier from real value to theoretical value of the displacement control of IPMC.展开更多
This investigation and morphology analysis of porous structure of some kinds of natural materials such as chicken eggshell, partridge eggshell, pig bone, and seeds of mung bean, soja, ginkgo, lotus seed, as well as th...This investigation and morphology analysis of porous structure of some kinds of natural materials such as chicken eggshell, partridge eggshell, pig bone, and seeds of mung bean, soja, ginkgo, lotus seed, as well as the epidermis of apples, with SEM (Scanning Electronic Microscope) showed that natural structures’ pores can be classified into uniform pores, gradient pores and multi pores from the viewpoint of the distribution variation of pore density, size and geometry. Furthermore, an optimal design of porous bearings was for the first time developed based on the gradient configuration of natural materials. The bionic design of porous structures is predicted to be widely developed and applied in the fields of materials and mechanical engineering in the future.展开更多
Using an electron microscope to observe the microstructure of a porcupine quills cross-section and a bionic method,a new bionic structure was proposed.The performance of the structure in terms of energy absorption,max...Using an electron microscope to observe the microstructure of a porcupine quills cross-section and a bionic method,a new bionic structure was proposed.The performance of the structure in terms of energy absorption,maximum impact force withstood,and impact force efficiency was evaluated using Ansys finite element simulation software to simulate the structure's impact.To examine the impact of ribs on the structural performance of the bionic porcupine quills,a control structure was developed.According to the results of the finite element simulation,the presence of ribs in the Bionic porcupine quills structure can transfer stress uniformly to the overall structure and share stress for some of the rupture-prone regions.Ribs reduce stress concentration in specific areas and increase the impact force efficiency of the structure.The SEA and IFE values of bionic porcupine quills were 30.01 kJ/kg and 84.22%,respectively.The structure is then optimized for parameter design in order to find the optimal structure by response surface in order to improve the structure's SEA and decrease its MIF.In order to evaluate the precision of the response surface,the optimal structure predicted is validated using finite element simulation.展开更多
A new process for the fabrication of sharkskin bionic structures on metal surfaces is proposed.The sharkskin bionic surface was successfully machined on the surface of IN718 by laser sequencing of the abrasive belt su...A new process for the fabrication of sharkskin bionic structures on metal surfaces is proposed.The sharkskin bionic surface was successfully machined on the surface of IN718 by laser sequencing of the abrasive belt surface,laser processing of the layered scale-like structure,and ribbed texture grinding.The flexible contact properties of belt grinding allow ribbed structures to be machined uniformly on a hierarchical,scale-like microstructure.Sharkskin bionic microstructures with radii greater than 75µm were prepared after parameter optimisation.The influence of processing parameters on the geometrical accuracy of the microstructure was investigated,the microstructure microform and elemental distribution were analyzed,and the relationship between the ribbed microstructure and chemical properties of the surface of the bionic sharkskin on wettability was revealed.The results indicate that reducing the laser power and increasing the laser scan rate can reduce the laser thermal effect and improve the microstructure processing accuracy.The laser ablation process is accompanied by a violent chemical reaction that introduces a large amount of oxygen and carbon elements and infiltrates them at a certain depth.The wettability of the surface undergoes a transition from hydrophilic(contact angle 69.72°)to hydrophobic(contact angle 131.56°)due to the adsorption of C-C/C-H and the reduction of C=O/O=C-O during the placement process.The ribbed microstructure changes the solid-liquid contact on the surface into a solid-liquid-gas contact,which has an enhanced effect on hydrophobicity.This study is a valuable guide to the processing of hydrophobic layered bionic microstructures.展开更多
Lightweight porous materials with high load-bearing,damage tolerance and energy absorption(EA)as well as intelligence of shape recovery after material deformation are beneficial and critical for many applications,e.g....Lightweight porous materials with high load-bearing,damage tolerance and energy absorption(EA)as well as intelligence of shape recovery after material deformation are beneficial and critical for many applications,e.g.aerospace,automobiles,electronics,etc.Cuttlebone produced in the cuttlefish has evolved vertical walls with the optimal corrugation gradient,enabling stress homogenization,significant load bearing,and damage tolerance to protect the organism from high external pressures in the deep sea.This work illustrated that the complex hybrid wave shape in cuttlebone walls,becoming more tortuous from bottom to top,creates a lightweight,load-bearing structure with progressive failure.By mimicking the cuttlebone,a novel bionic hybrid structure(BHS)was proposed,and as a comparison,a regular corrugated structure and a straight wall structure were designed.Three types of designed structures have been successfully manufactured by laser powder bed fusion(LPBF)with NiTi powder.The LPBF-processed BHS exhibited a total porosity of 0.042% and a good dimensional accuracy with a peak deviation of 17.4μm.Microstructural analysis indicated that the LPBF-processed BHS had a strong(001)crystallographic orientation and an average size of 9.85μm.Mechanical analysis revealed the LPBF-processed BHS could withstand over 25000 times its weight without significant deformation and had the highest specific EA value(5.32 J·g^(−1))due to the absence of stress concentration and progressive wall failure during compression.Cyclic compression testing showed that LPBF-processed BHS possessed superior viscoelastic and elasticity energy dissipation capacity.Importantly,the uniform reversible phase transition from martensite to austenite in the walls enables the structure to largely recover its pre-deformation shape when heated(over 99% recovery rate).These design strategies can serve as valuable references for the development of intelligent components that possess high mechanical efficiency and shape memory capabilities.展开更多
Inspired by the crystal microstructure of metals and the bamboo,the bionic porous NiTi structures with the porosities in the range of 75.8%–84.9%were built via selective laser melting(SLM).The compression behavior an...Inspired by the crystal microstructure of metals and the bamboo,the bionic porous NiTi structures with the porosities in the range of 75.8%–84.9%were built via selective laser melting(SLM).The compression behavior and the failure mechanisms of the porous NiTi structures were evaluated.It demonstrated an increase in the elastic modulus and ultimate strength when the porosity was decreased,from 3.06 to 7.66 GPa and from 34.1 to 147.6 MPa,respectively.The relationship between the elastic modulus and the porosity obtained by the finite element analysis exhibited similar tendency with the experiment,and agreed well with the Gibson-Ashby model’s prediction.Based on the theoretical model above and the observation of the deformation processing,the plastic deformation behavior and failure mechanisms of the SLMed porous NiTi structures were analyzed.展开更多
Current research on wind energy piezoelectric energy harvesters(PEHs)mainly focuses on tandem smooth cylinder energy harvesters;however,the traditional tandem smooth cylinder energy harvester has low voltage output an...Current research on wind energy piezoelectric energy harvesters(PEHs)mainly focuses on tandem smooth cylinder energy harvesters;however,the traditional tandem smooth cylinder energy harvester has low voltage output and narrow energy harvest bandwidth.In this study,a D-type bionic fin is designed and installed on a smooth cylindrical surface to improve its performance.The influence of the spacing ratio on the amplitude and voltage of PEHs with D-type bionic fins added under elastic interference was investigated through wind tunnel tests.Three installation positions were designed:only installed upstream,only installed downstream,and not installed upstream and downstream(BARE).It was found that the maximum displacement of the upstream PEH(UPEH)was not apparently affected by the D-type bionic fin.Contrastingly,the fin changed the maximum amplitude from a small to a large spacing ratio for the downstream PEH(DPEH).D-type bionic fin can enhance energy harvest performance by coupling“coupled vortex-induced vibration”and wake induced galloping,increasing the surface velocity of PEHs and expanding the bandwidth of the voltage harvested by the PEHs.Analysis of the power under the experimental wind speed showed that installing D-type fins in the PEHs can increase the output power of the upstream and downstream PEHs by 392.28%and 13%,respectively,compared with that of the BARE-PEH.Additionally,computational fluid dynamics was used to analyze the flow pattern,wake structure,and lift coefficient of the PEHs,and to explain why the upstream D-type bionic fin installation has an impact on the harvest performance of the upstream and downstream PEHs at a spacing ratio of 1.5.This study provides an efficient and simple scheme for designing wind PEHs.展开更多
The ability of organisms to adjust to environmental changes offers valuable insights into the development and creation of innovative smart systems. As requirements increase, the ability of smart materials to change th...The ability of organisms to adjust to environmental changes offers valuable insights into the development and creation of innovative smart systems. As requirements increase, the ability of smart materials to change their shapes has become a broader aim beyond their original capabilities. In contrast to conventional manufacturing methods, additive manufacturing (AM) skillfully combines precise three-dimensional structures and the intricate response mechanisms of biological organisms with smart materials. This combination enables the production of smart bionic structures with programmable shapes and features. Trends such as dynamic modulation, responsive- ness to multiple stimuli, and the integration of functions are emerging as significant in the development of smart bionic structures. This review first presents smart structures that nature has designed and built in various organ- isms, highlighting the relationship between the structural characteristics and patterns of deformation. The review then discusses how smart bionic structures developed using AM techniques respond to different stimuli. Addi- tionally, the potential uses of smart bionic structures in biomedicine, intelligent robotics, origami construction, and aerospace are discussed. Finally, the challenges and future prospects for smart bionic structures are exam- ined with the goal of offering innovative solutions for creating the next generation of smart systems through interdisciplinary research.展开更多
Passive bionic feet,known for their human-like compliance,have garnered attention for their potential to achieve notable environmental adaptability.In this paper,a method was proposed to unifying passive bionic feet s...Passive bionic feet,known for their human-like compliance,have garnered attention for their potential to achieve notable environmental adaptability.In this paper,a method was proposed to unifying passive bionic feet static supporting stability and dynamic terrain adaptability through the utilization of the Rigid-Elastic Hybrid(REH)dynamics model.First,a bionic foot model,named the Hinge Tension Elastic Complex(HTEC)model,was developed by extracting key features from human feet.Furthermore,the kinematics and REH dynamics of the HTEC model were established.Based on the foot dynamics,a nonlinear optimization method for stiffness matching(NOSM)was designed.Finally,the HTEC-based foot was constructed and applied onto BHR-B2 humanoid robot.The foot static stability is achieved.The enhanced adaptability is observed as the robot traverses square steel,lawn,and cobblestone terrains.Through proposed design method and structure,the mobility of the humanoid robot is improved.展开更多
基金Wuxi University Research Start-up Fund for Introduced Talents(Grant No:2024r031)Technology Development Contract(Contract Registration Number:2024320205000963)+1 种基金National Natural Science Foundation of China(Grant No.52275288)Ningbo Key Research and Development Plan(Grant No.2023Z022).
文摘To solve the problem of abnormal abrasion of Cu-Based Friction Materials(CBFMs),Bionic Non-Smooth Surface(BNS)on friction surface of CBFMs was constructed based on bionic principles,and the optimal bionic prototype was selected by Finite Element Method(FEM).In addition,the bionic parameters were optimized by Response Surface Method(RSM).Samples holding BNS were prepared by Laser Processing,tribological properties were tested by a Friction and Wear Tester and worn surface morphology was characterized by a Scanning Electron Microscope(SEM).The results showed that BNS on friction surface could regulate the stress distribution and alleviate the peak stress.Among all samples,the coupled texture of pit-hexagonal got the minimum peak stress.During braking,bionic texture could also collect wear debris or change the motion forms from sliding to rotation,which can reduce abnormal abrasion.The wear rate was reduced by 19.31%.The results in this paper can provide a new idea for enhancing the tribological properties of CBFMs,and can also lay the foundation for further research of bionic tribology.
基金supported by the Open Fund of Science and Technology on Thermal Energy and Power Laboratory[TPL2021A02]the State Key Laboratory of Hydroscience and Engineering[sklhse-2023-E-01].
文摘Centrifugal pumps are extensively employed in ocean engineering,such as ship power systems,water transportation,and mineral exploitation.Pressure fluctuation suppression is essential for the operation stability and service life of the centrifugal pump.In this paper,a new method of bionic structure is proposed for the blade surface of a centrifugal pump,which is inspired by the fish scale and comprises a leading edge,a trailing edge,and two symmetrical side edges.This fish scale structure is applied to the blade pressure and suction surfaces,and an impeller with a fish scale structure is constructed.A test rig for a centrifugal pump is developed to determine the pressure fluctuation in the pump with a prototype impeller and fish scale structure impeller.Results reveal that the dominant frequency of pressure fluctuation in volute is the blade passing frequency(f_(bpf))of 193.33 Hz,which is triggered by the interaction between the tongue and the impeller.The bionic structure of the fish scale effectively suppresses the pressure fluctuation amplitude at f_(bpf).From flow rates of 0.6 Q_(d)to 1.2 Q_(d),the average suppressions in pressure fluctuation amplitudes at f_(bpf)are 20.98%,5.85%,19.20%,and 25.77%.
基金supported by the National Natural Science Foundation of China(52375372)the National Key Laboratory of Particle Transport and Separation Technology(KWKF-2024-3).
文摘Heterogeneous manufacturing is a topic that continues to receive attention.As an emerging manufacturing technology,additive manufacturing can provide strong technical support for heterogeneous manufacturing.In this study,both homogeneous and heterogeneous composite tubular bionic components were fabricated based on the cold metal transition technology,and the influence of deposition current on the microstructure and mechanical properties of the components was studied.The results show that the interface of the as-deposited heterogeneous composite component is well bonded,and there is an obvious mechanical interlocking structure.The compressive yield strength and elongation of the heterogeneous composite components are higher than those of the homogeneous components,and are positively correlated with the deposition current.Due to the fluctuation of element content,there are a large number of fine grain structures at the interface of the heterogeneous composite components,which increases the mechanical properties.
基金This work is supported by the National Natural Science Foundation of China(Grant Nos.52205057 and 52175052)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.22KJB460002)+2 种基金China Postdoctoral Science Foundation(Grant No.2022M723702)Taizhou Science and Technology Plan Project(Grant No.22gyb42)in part by the Youth Talent Development Program of Jiangsu University.
文摘As a global concern,environmental protection and energy conservation have attracted significant attention.Due to the large carbon emission of electricity,promoting green and low-carbon transformation of the power industry via the synergistic development of clean energy sources is essential.Rotating machinery plays a crucial role in pumped storage,hydropower generation,and nuclear power generation.Inspired by bionics,non-smooth features of creatures in nature have been introduced into the structure design of efficient rotating machines.First,the concept and classification of bionics are described.Then,the representative applications of non-smooth surface bionic structures in rotating machineries are systematically and comprehensively reviewed,such as groove structure,pit structure,and other non-smooth surfaces.Finally,conclusions are drawn and future directions are presented.The effective design of a bionic structure contributes toward noise reduction,drag reduction and efficiency improvement of rotating machineries.Green and ecological rotating machinery will remarkably reduce energy consumption and contribute to the realization of the“double carbon”goal.
基金National Key R&D Program of China(No.2018YFB1105100)National Natural Science Foundation of China(No.51975246)+5 种基金Jilin Province Science and Technology Development Plan(No.YDZJ202101ZYTS134)State Key Laboratory of Automotive Simulation and Control—ziyoutansuoxiangmu(202013)Open Project Program of Key Laboratory for Cross-Scale Micro and Nano Manufacturing,Ministry of Education,Changchun University of Science and Technology(CMNM-KF202109)Program for JLU Science and Technology Innovative Research Team(No.2019TD-34)Interdisciplinary Research Fund for Doctoral Postgraduates of Jilin University(No.101832020DJX052)Interdisciplinary Cultivation Project for Young Teachers and Students(No.415010300078)。
文摘Each specific structure of organisms is the best choice under specific circumstances.The excellent characteristic structures of these organisms have great application potential in the design and multi-functional optimization of energy-absorbing structures such as vehicle collisions,satellite landings,and military equipment.In this paper,using the principle of structural bionics,using the advantages of the honeycomb structure and the light weight and high strength of beetle elytra,four bionic lattice structures are studied:CH,ZPRH,SCH and IBE.Using NiTi shape memory alloy,a unique material as the base material,samples are prepared using selective laser melting(SLM)technology.By comparing the test results of the quasi-static compression test with the results of the numerical simulation,it is found that compared with the other three bionic lattice structures,the SCH structure has the best energy absorption effect in the effective stroke in the test,and the specific energy absorption can reach 6.32 J/g.ZPRH,SCH,and IBE structures not only have good and stable deformation behavior,but also have excellent impact resistance and shape memory properties.The design of these structures provides a reference for the design of anti-shock cushioning structures with self-recovery functions in the future.
基金The project supported by the National Natural Science Foundation of China(59578032)the Key Project of the Ninth Five-Year Plan(96221030202)
文摘A novel single-step method is proposed for the analysis of dynamic response of visco-elastic structures containing non-smooth contactable interfaces. In the method, a two-level algorithm is employed for dealing with a nonlinear boundary condition caused by the dynamic contact of interfaces. At the first level, an explicit method is adopted to calculate nodal displacements of global viscoelastic system without considering the effect of dynamic contact of interfaces and at the second level, by introducing contact conditions of interfaces, a group of equations of lower order is derived to calculate dynamic contact normal and shear forces on the interfaces. The method is convenient and efficient for the analysis of problems of dynamic contact. The accuracy of the method is of the second order and the numerical stability condition is wider than that of other explicit methods.
基金National Natural Science Foundation(NNSF)of China under Grant No.51478132Guangzhou City College Scientific Research Project under Grant No.120163017
文摘This study investigates the effectiveness of the non-smooth semi-active control algorithm on suppressing the vibration performance of a building structure subjected to seismic waves. According to the Lyapunov stability theory, it has bene proven that the non-smooth semi-active control algorithm can achieve a finite-time stability of the vibration relative to the isolation layer of a building structure. Through numerical simulation of two buildings with different parameters subjected to the input of a seismic wave, the vibration conditions of passive control, LQR semi-active control and non-smooth semiactive control are compared and analyzed. The simulation results show that the non-smooth semi-active control algorithm has a better robustness and effectiveness in restraining the impact of earthquakes on the structure.
基金Project(51275102)supported by the National Natural Science Foundation of ChinaProject(HEUCF140713)supported by the Fundamental Research Funds for the Central Universities,China
文摘Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve flexible connector,the IPMC linear driving unit simulation model is built and the IPMC material-driving dynamic control structure of bionic gill unit is developed.Meanwhile,through the stress analysis of bionic gill plate and the motion simulation of bionic gill unit,it is verified that various dynamic control and active control of the jet orifice under the condition of different mainstream field velocities will be taken by using IPMC material-driving.Moreover,the large-deflection deformation of bionic gill plate under dynamic pressure and the comparative analysis with that of a rigid gill plate is studied,leading to the achievement of approximate revised modifier from real value to theoretical value of the displacement control of IPMC.
文摘This investigation and morphology analysis of porous structure of some kinds of natural materials such as chicken eggshell, partridge eggshell, pig bone, and seeds of mung bean, soja, ginkgo, lotus seed, as well as the epidermis of apples, with SEM (Scanning Electronic Microscope) showed that natural structures’ pores can be classified into uniform pores, gradient pores and multi pores from the viewpoint of the distribution variation of pore density, size and geometry. Furthermore, an optimal design of porous bearings was for the first time developed based on the gradient configuration of natural materials. The bionic design of porous structures is predicted to be widely developed and applied in the fields of materials and mechanical engineering in the future.
基金supported by the National Natural Science Foundation of China(No.11972158)the Postgraduate Scientific Research Innovation Project of Hunan Province(No.CX20221044)the Military Commission Science and Technology Committee Basic Strengthening Program Technology Fund(No.2020-JCJQ-JJ-356)and(No.2019-JCJQ-JJ-150).
文摘Using an electron microscope to observe the microstructure of a porcupine quills cross-section and a bionic method,a new bionic structure was proposed.The performance of the structure in terms of energy absorption,maximum impact force withstood,and impact force efficiency was evaluated using Ansys finite element simulation software to simulate the structure's impact.To examine the impact of ribs on the structural performance of the bionic porcupine quills,a control structure was developed.According to the results of the finite element simulation,the presence of ribs in the Bionic porcupine quills structure can transfer stress uniformly to the overall structure and share stress for some of the rupture-prone regions.Ribs reduce stress concentration in specific areas and increase the impact force efficiency of the structure.The SEA and IFE values of bionic porcupine quills were 30.01 kJ/kg and 84.22%,respectively.The structure is then optimized for parameter design in order to find the optimal structure by response surface in order to improve the structure's SEA and decrease its MIF.In order to evaluate the precision of the response surface,the optimal structure predicted is validated using finite element simulation.
基金supported by the National Natural Science Foundation of China[Grant No.52175377]the National Science and Technology Major Project[Grant No.2017-VII-0002-0095]the Graduate Scientific Research and Innovation Foundation of Chongqing[Grant No.CYB22009].
文摘A new process for the fabrication of sharkskin bionic structures on metal surfaces is proposed.The sharkskin bionic surface was successfully machined on the surface of IN718 by laser sequencing of the abrasive belt surface,laser processing of the layered scale-like structure,and ribbed texture grinding.The flexible contact properties of belt grinding allow ribbed structures to be machined uniformly on a hierarchical,scale-like microstructure.Sharkskin bionic microstructures with radii greater than 75µm were prepared after parameter optimisation.The influence of processing parameters on the geometrical accuracy of the microstructure was investigated,the microstructure microform and elemental distribution were analyzed,and the relationship between the ribbed microstructure and chemical properties of the surface of the bionic sharkskin on wettability was revealed.The results indicate that reducing the laser power and increasing the laser scan rate can reduce the laser thermal effect and improve the microstructure processing accuracy.The laser ablation process is accompanied by a violent chemical reaction that introduces a large amount of oxygen and carbon elements and infiltrates them at a certain depth.The wettability of the surface undergoes a transition from hydrophilic(contact angle 69.72°)to hydrophobic(contact angle 131.56°)due to the adsorption of C-C/C-H and the reduction of C=O/O=C-O during the placement process.The ribbed microstructure changes the solid-liquid contact on the surface into a solid-liquid-gas contact,which has an enhanced effect on hydrophobicity.This study is a valuable guide to the processing of hydrophobic layered bionic microstructures.
基金supported by the National Natural Science Foundation of China(Grant No.52225503)National Key Research and Development Program of China(Grant No.2022YFB3805701)+1 种基金Development Program of Jiangsu Province(Grant Nos.BE2022069 and BE2022069-1)Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX21-0207).
文摘Lightweight porous materials with high load-bearing,damage tolerance and energy absorption(EA)as well as intelligence of shape recovery after material deformation are beneficial and critical for many applications,e.g.aerospace,automobiles,electronics,etc.Cuttlebone produced in the cuttlefish has evolved vertical walls with the optimal corrugation gradient,enabling stress homogenization,significant load bearing,and damage tolerance to protect the organism from high external pressures in the deep sea.This work illustrated that the complex hybrid wave shape in cuttlebone walls,becoming more tortuous from bottom to top,creates a lightweight,load-bearing structure with progressive failure.By mimicking the cuttlebone,a novel bionic hybrid structure(BHS)was proposed,and as a comparison,a regular corrugated structure and a straight wall structure were designed.Three types of designed structures have been successfully manufactured by laser powder bed fusion(LPBF)with NiTi powder.The LPBF-processed BHS exhibited a total porosity of 0.042% and a good dimensional accuracy with a peak deviation of 17.4μm.Microstructural analysis indicated that the LPBF-processed BHS had a strong(001)crystallographic orientation and an average size of 9.85μm.Mechanical analysis revealed the LPBF-processed BHS could withstand over 25000 times its weight without significant deformation and had the highest specific EA value(5.32 J·g^(−1))due to the absence of stress concentration and progressive wall failure during compression.Cyclic compression testing showed that LPBF-processed BHS possessed superior viscoelastic and elasticity energy dissipation capacity.Importantly,the uniform reversible phase transition from martensite to austenite in the walls enables the structure to largely recover its pre-deformation shape when heated(over 99% recovery rate).These design strategies can serve as valuable references for the development of intelligent components that possess high mechanical efficiency and shape memory capabilities.
基金This work was financially supported by the Natural Science Foundation of Jilin Province(No.20220101216JC)the National Natural Science Foundation of China(No.52235006)+1 种基金the National Natural Science Foundation of China(No.52025053)the National Natural Science Foundation of China(No.52105303).
文摘Inspired by the crystal microstructure of metals and the bamboo,the bionic porous NiTi structures with the porosities in the range of 75.8%–84.9%were built via selective laser melting(SLM).The compression behavior and the failure mechanisms of the porous NiTi structures were evaluated.It demonstrated an increase in the elastic modulus and ultimate strength when the porosity was decreased,from 3.06 to 7.66 GPa and from 34.1 to 147.6 MPa,respectively.The relationship between the elastic modulus and the porosity obtained by the finite element analysis exhibited similar tendency with the experiment,and agreed well with the Gibson-Ashby model’s prediction.Based on the theoretical model above and the observation of the deformation processing,the plastic deformation behavior and failure mechanisms of the SLMed porous NiTi structures were analyzed.
基金Supported by National Natural Science Foundation of China(Grant No.21978202).
文摘Current research on wind energy piezoelectric energy harvesters(PEHs)mainly focuses on tandem smooth cylinder energy harvesters;however,the traditional tandem smooth cylinder energy harvester has low voltage output and narrow energy harvest bandwidth.In this study,a D-type bionic fin is designed and installed on a smooth cylindrical surface to improve its performance.The influence of the spacing ratio on the amplitude and voltage of PEHs with D-type bionic fins added under elastic interference was investigated through wind tunnel tests.Three installation positions were designed:only installed upstream,only installed downstream,and not installed upstream and downstream(BARE).It was found that the maximum displacement of the upstream PEH(UPEH)was not apparently affected by the D-type bionic fin.Contrastingly,the fin changed the maximum amplitude from a small to a large spacing ratio for the downstream PEH(DPEH).D-type bionic fin can enhance energy harvest performance by coupling“coupled vortex-induced vibration”and wake induced galloping,increasing the surface velocity of PEHs and expanding the bandwidth of the voltage harvested by the PEHs.Analysis of the power under the experimental wind speed showed that installing D-type fins in the PEHs can increase the output power of the upstream and downstream PEHs by 392.28%and 13%,respectively,compared with that of the BARE-PEH.Additionally,computational fluid dynamics was used to analyze the flow pattern,wake structure,and lift coefficient of the PEHs,and to explain why the upstream D-type bionic fin installation has an impact on the harvest performance of the upstream and downstream PEHs at a spacing ratio of 1.5.This study provides an efficient and simple scheme for designing wind PEHs.
基金supported by National Natural Science Foundation of China(Grant Nos.52235006,52025053)National Key Research and Development Program of China(Grant No.2022YFB4600500).
文摘The ability of organisms to adjust to environmental changes offers valuable insights into the development and creation of innovative smart systems. As requirements increase, the ability of smart materials to change their shapes has become a broader aim beyond their original capabilities. In contrast to conventional manufacturing methods, additive manufacturing (AM) skillfully combines precise three-dimensional structures and the intricate response mechanisms of biological organisms with smart materials. This combination enables the production of smart bionic structures with programmable shapes and features. Trends such as dynamic modulation, responsive- ness to multiple stimuli, and the integration of functions are emerging as significant in the development of smart bionic structures. This review first presents smart structures that nature has designed and built in various organ- isms, highlighting the relationship between the structural characteristics and patterns of deformation. The review then discusses how smart bionic structures developed using AM techniques respond to different stimuli. Addi- tionally, the potential uses of smart bionic structures in biomedicine, intelligent robotics, origami construction, and aerospace are discussed. Finally, the challenges and future prospects for smart bionic structures are exam- ined with the goal of offering innovative solutions for creating the next generation of smart systems through interdisciplinary research.
基金supported by the National Natural Science Foundation of China(Grant No.62073041)the Open Fund of Laboratory of Aerospace Servo Actuation and Transmission(Grant No.LASAT-2023A04)the Fundamental Research Funds for the Central Universities(Grant Nos.2024CX06011,2024CX06079)。
文摘Passive bionic feet,known for their human-like compliance,have garnered attention for their potential to achieve notable environmental adaptability.In this paper,a method was proposed to unifying passive bionic feet static supporting stability and dynamic terrain adaptability through the utilization of the Rigid-Elastic Hybrid(REH)dynamics model.First,a bionic foot model,named the Hinge Tension Elastic Complex(HTEC)model,was developed by extracting key features from human feet.Furthermore,the kinematics and REH dynamics of the HTEC model were established.Based on the foot dynamics,a nonlinear optimization method for stiffness matching(NOSM)was designed.Finally,the HTEC-based foot was constructed and applied onto BHR-B2 humanoid robot.The foot static stability is achieved.The enhanced adaptability is observed as the robot traverses square steel,lawn,and cobblestone terrains.Through proposed design method and structure,the mobility of the humanoid robot is improved.
