This study investigates the vibration and acoustic properties of porous foam functionally graded(FG)plates under the influence of the temperature field.The dynamics equations of the system are established based on Ham...This study investigates the vibration and acoustic properties of porous foam functionally graded(FG)plates under the influence of the temperature field.The dynamics equations of the system are established based on Hamilton's principle by using the higher-order shear deformation theory under the linear displacement-strain assumption.The displacement shape function is assumed according to the four-sided simply-supported(SSSS)boundary condition,and the characteristic equations of the system are derived by combining the motion control equations.The theoretical model of vibro-acoustic coupling is established by using the acoustic theory and fluid-structure coupling solution method under the simple harmonic acoustic wave.The system's natural frequency and sound transmission loss(STL)are obtained through programming calculations and compared with the literature and COMSOL simulation to verify the validity and reliability of the theoretical model.The effects of various factors,such as temperature,porosity coefficients,gradient index,core thickness,width-to-thickness ratio on the vibration,and STL characteristics of the system,are discussed.The results provide a theoretical basis for the application of porous foam FG plates in engineering to optimize vibration and sound transmission properties.展开更多
A hybrid method combined the reduced Sequential Quadratic Programming(SQP)method with the harmonic balance method has been developed to analyze the characteristics of mode localization and internal resonance of nonlin...A hybrid method combined the reduced Sequential Quadratic Programming(SQP)method with the harmonic balance method has been developed to analyze the characteristics of mode localization and internal resonance of nonlinear bladed disks.With the aid of harmonic balance method,the nonlinear equality constraints for the constrained optimization problem are constructed.The reduced SQP method is then utilized to deal with the original constrained optimization problem.Applying the null space decomposition technique to the harmonic balance algebraic equations results in the vanishing of the nonlinear equality constraints and a simple optimization problem involving only upper and lower bound constraints on the optimization variables is formed and solved.Finally,numerical results are given for several test examples to validity the proposed method.The efficiency of the solution method to trace the family of energy dependent nonlinear modes is illustrated.The localization nonlinear normal modes of bladed disks related to various types of internal resonances are explored.展开更多
In this paper,an efficient calculation method based on discrete Fourier transformation is developed for evaluating elastic load induced elastic deformation fields of film-substrate system.Making use of 2 D discrete Fo...In this paper,an efficient calculation method based on discrete Fourier transformation is developed for evaluating elastic load induced elastic deformation fields of film-substrate system.Making use of 2 D discrete Fourier transformation,the elastic fields induced by Hertz load is harvested in frequency domain,and the displacement and stress fields across the interface are enforced to satisfy the elasticity conditions for each Fourier modes.Given arbitrary distributed stress field at free surface plane of the three types of film-substrate systems,unique resultant elastic field within the can be harvested.Hertz load of half space,elastic film on elastic substrate,elastic film on rigid substrate system and elastic film-substrate system with three types of imperfect interface models are investigated:(1)the spring-like imperfect interface model which can be described as:u^fk|zf=-h-u^sk|z^s=0=KTσKZ and u^fz|zf=-h-u^sz|z^s=0=KNσZZ;(2)the dislocation-like interface model,where interface displacement and stress components relation can be described as:u^fi|zf=0=k^uiju^si|z^s=0 andσ^fiz|z^f=0=σ^siz|zf=0=σ^siz|z^s=0;(3)the force-like interface model,where interface displacement and stress components relation can be described as:u^fi|z^f=0=u^si|z^s=0 andσ^fiz|z^f=0=k^tijσ^siz|z^s=0 respectively.Finally,several simulation examples are performed for verification of the reliability and efficiency of the proposed semi-analytical methods.展开更多
Anode free lithium metal batteries(AF-LMBs)have conspicuous advantages both in energy density and the compatibility of battery manufacturing process.However,the limited cycle life of AF-LMBs is a crucial factor hinder...Anode free lithium metal batteries(AF-LMBs)have conspicuous advantages both in energy density and the compatibility of battery manufacturing process.However,the limited cycle life of AF-LMBs is a crucial factor hindering its practical application.Fluorinated or nitride artificial inorganic solid electrolyte interphase(SEI)has been found as an effective method to prolong the lifespan of AF-LMBs.Herein,by investigating the impact of nano-sized inorganic gradient layers(LiF or Li3N)on initial Li deposition behavior,we notice that the Li^(+) diffusion barrier and the deposition morphology are highly depended on the thickness of inorganic layers.Thicker protective layers cause larger overpotential as well as more aggregated Li^(+) distribution.This study reveals that the ideal SEI should be synthesized thin and uniformly enough and uncontrollable artificial SEI can cause damage to the lifespan of AF-LMBs.展开更多
This paper presents a new multiobjective discrete optimization method for the engineering design of dynamic problems.A discrete combinatorial optimization problem is solved using a particle swarm optimization algorith...This paper presents a new multiobjective discrete optimization method for the engineering design of dynamic problems.A discrete combinatorial optimization problem is solved using a particle swarm optimization algorithm coupled with a stair‐form interpolation model.To address multiobjective optimization issues,a weighted average approach is implemented to convert the multiobjective optimization problem into an equivalent single‐objective optimization problem.Design con-straints are taken into consideration by using the penalty function strategy.The proposed method is first verified with a 10‐bar truss structure design problem,where the cross‐sectional area of each bar is optimized to minimize both volume and node displacement.Second,the dynamic issue for hybrid composite laminates is investigated by maximizing the fundamental frequency and minimizing the cost.The results reveal that the optimized results generated by the proposed method agree well with those from other approaches.展开更多
基金Project supported by the National Natural Science Foundation of China(No.11972082)。
文摘This study investigates the vibration and acoustic properties of porous foam functionally graded(FG)plates under the influence of the temperature field.The dynamics equations of the system are established based on Hamilton's principle by using the higher-order shear deformation theory under the linear displacement-strain assumption.The displacement shape function is assumed according to the four-sided simply-supported(SSSS)boundary condition,and the characteristic equations of the system are derived by combining the motion control equations.The theoretical model of vibro-acoustic coupling is established by using the acoustic theory and fluid-structure coupling solution method under the simple harmonic acoustic wave.The system's natural frequency and sound transmission loss(STL)are obtained through programming calculations and compared with the literature and COMSOL simulation to verify the validity and reliability of the theoretical model.The effects of various factors,such as temperature,porosity coefficients,gradient index,core thickness,width-to-thickness ratio on the vibration,and STL characteristics of the system,are discussed.The results provide a theoretical basis for the application of porous foam FG plates in engineering to optimize vibration and sound transmission properties.
基金The authors would like to thank the sponsor of the National Natural Science Foundation of China through grant No.11502261the Aeronautical Science Foundation of China under award No.2015ZB04002The sponsor of the Beijing Institute of Technology Research Fund Program for Young Scholars is gratefully acknowledged by the authors.
文摘A hybrid method combined the reduced Sequential Quadratic Programming(SQP)method with the harmonic balance method has been developed to analyze the characteristics of mode localization and internal resonance of nonlinear bladed disks.With the aid of harmonic balance method,the nonlinear equality constraints for the constrained optimization problem are constructed.The reduced SQP method is then utilized to deal with the original constrained optimization problem.Applying the null space decomposition technique to the harmonic balance algebraic equations results in the vanishing of the nonlinear equality constraints and a simple optimization problem involving only upper and lower bound constraints on the optimization variables is formed and solved.Finally,numerical results are given for several test examples to validity the proposed method.The efficiency of the solution method to trace the family of energy dependent nonlinear modes is illustrated.The localization nonlinear normal modes of bladed disks related to various types of internal resonances are explored.
基金supported by the National Natural Science Foundation of China(Grants 11702023 and 11972081)。
文摘In this paper,an efficient calculation method based on discrete Fourier transformation is developed for evaluating elastic load induced elastic deformation fields of film-substrate system.Making use of 2 D discrete Fourier transformation,the elastic fields induced by Hertz load is harvested in frequency domain,and the displacement and stress fields across the interface are enforced to satisfy the elasticity conditions for each Fourier modes.Given arbitrary distributed stress field at free surface plane of the three types of film-substrate systems,unique resultant elastic field within the can be harvested.Hertz load of half space,elastic film on elastic substrate,elastic film on rigid substrate system and elastic film-substrate system with three types of imperfect interface models are investigated:(1)the spring-like imperfect interface model which can be described as:u^fk|zf=-h-u^sk|z^s=0=KTσKZ and u^fz|zf=-h-u^sz|z^s=0=KNσZZ;(2)the dislocation-like interface model,where interface displacement and stress components relation can be described as:u^fi|zf=0=k^uiju^si|z^s=0 andσ^fiz|z^f=0=σ^siz|zf=0=σ^siz|z^s=0;(3)the force-like interface model,where interface displacement and stress components relation can be described as:u^fi|z^f=0=u^si|z^s=0 andσ^fiz|z^f=0=k^tijσ^siz|z^s=0 respectively.Finally,several simulation examples are performed for verification of the reliability and efficiency of the proposed semi-analytical methods.
基金supported by the National Natural Scientific Foundation of China(No.22379014)Shanxi key research and development program(No.202102060301011)。
文摘Anode free lithium metal batteries(AF-LMBs)have conspicuous advantages both in energy density and the compatibility of battery manufacturing process.However,the limited cycle life of AF-LMBs is a crucial factor hindering its practical application.Fluorinated or nitride artificial inorganic solid electrolyte interphase(SEI)has been found as an effective method to prolong the lifespan of AF-LMBs.Herein,by investigating the impact of nano-sized inorganic gradient layers(LiF or Li3N)on initial Li deposition behavior,we notice that the Li^(+) diffusion barrier and the deposition morphology are highly depended on the thickness of inorganic layers.Thicker protective layers cause larger overpotential as well as more aggregated Li^(+) distribution.This study reveals that the ideal SEI should be synthesized thin and uniformly enough and uncontrollable artificial SEI can cause damage to the lifespan of AF-LMBs.
基金The National Natural Science Foundation of China,Grant/Award Number:11972082supported by the National Science Foundation of China(No.11972082)the Beijing Institute of Technology Research Fund Program for Young Scholars,China.
文摘This paper presents a new multiobjective discrete optimization method for the engineering design of dynamic problems.A discrete combinatorial optimization problem is solved using a particle swarm optimization algorithm coupled with a stair‐form interpolation model.To address multiobjective optimization issues,a weighted average approach is implemented to convert the multiobjective optimization problem into an equivalent single‐objective optimization problem.Design con-straints are taken into consideration by using the penalty function strategy.The proposed method is first verified with a 10‐bar truss structure design problem,where the cross‐sectional area of each bar is optimized to minimize both volume and node displacement.Second,the dynamic issue for hybrid composite laminates is investigated by maximizing the fundamental frequency and minimizing the cost.The results reveal that the optimized results generated by the proposed method agree well with those from other approaches.