In this paper an analytical method is proposed to investigate the vibration and power flows of periodically reinforced plate with general boundary conditions. Both the plate and stiffening beams are modeled as 3D stru...In this paper an analytical method is proposed to investigate the vibration and power flows of periodically reinforced plate with general boundary conditions. Both the plate and stiffening beams are modeled as 3D structural components, and the couplings at the interfaces are specified in terms of 3D elastic joints. The displacement function for each stiffening beam is expressed as a modified Fourier cosine series, and the transverse and in-plane displacements for the plate are similarly expressed as the 2D versions of the modified Fourier cosine series expansions. The unknown Fourier coefficients are calculated using the Rayleigh-Ritz technique. The key advantages of the proposed method include: 1) it is capable of dealing with arbitrary boundary and coupling conditions, 2) it allows modeling any number of reinforcing beams with arbitrary lengths, and 3) the structural intensity, power flows, and kinetic energy distributions are readily calculated analytically from the displacement functions through appropriate mathematical (differential) operations, to name a few. The power flow characteristics of periodically reinforced plates are studied against various influencing factors, such as, plate and beam boundary conditions, coupling conditions, excitation locations, and dislocations resulting from minor misplacement of a reinforcing beam.展开更多
Softening behavior of lath martensitic steels is related to the coarsening of laths and dislocation evolution during cyclic deformation.Involving the physical mechanism,we developed a dislocation-based model to study ...Softening behavior of lath martensitic steels is related to the coarsening of laths and dislocation evolution during cyclic deformation.Involving the physical mechanism,we developed a dislocation-based model to study the cyclic plastic response for lath martensitic steels.For a block,we proposed an interfacial dislocation evolution model to physically present the interaction between mobile dislocations in the block and interfacial dislocations by considering the coarsening mechanism of the laths.Moreover,the evolution behavior of backstress caused by dislocation pile up at the block boundary has been considered.Then,a hierarchical model based on the elastic-viscoplastic self-consistent(EVPSC)theory is developed,which can realize the scale transition among representative volume element(RVE),prior austenite grains(PAGs)and blocks.According to the proposed model,the effective mechanical responses including the cyclic hysteretic loop and peak stress at different cycles for lath martensitic steel have been theoretically predicted and investigated.展开更多
文摘In this paper an analytical method is proposed to investigate the vibration and power flows of periodically reinforced plate with general boundary conditions. Both the plate and stiffening beams are modeled as 3D structural components, and the couplings at the interfaces are specified in terms of 3D elastic joints. The displacement function for each stiffening beam is expressed as a modified Fourier cosine series, and the transverse and in-plane displacements for the plate are similarly expressed as the 2D versions of the modified Fourier cosine series expansions. The unknown Fourier coefficients are calculated using the Rayleigh-Ritz technique. The key advantages of the proposed method include: 1) it is capable of dealing with arbitrary boundary and coupling conditions, 2) it allows modeling any number of reinforcing beams with arbitrary lengths, and 3) the structural intensity, power flows, and kinetic energy distributions are readily calculated analytically from the displacement functions through appropriate mathematical (differential) operations, to name a few. The power flow characteristics of periodically reinforced plates are studied against various influencing factors, such as, plate and beam boundary conditions, coupling conditions, excitation locations, and dislocations resulting from minor misplacement of a reinforcing beam.
基金supported by the National Natural Science Foundation of China(Grant Nos.11988102,12002005,11632001,11521202)the Science Challenge Project(Grant No.TZ2018001).
文摘Softening behavior of lath martensitic steels is related to the coarsening of laths and dislocation evolution during cyclic deformation.Involving the physical mechanism,we developed a dislocation-based model to study the cyclic plastic response for lath martensitic steels.For a block,we proposed an interfacial dislocation evolution model to physically present the interaction between mobile dislocations in the block and interfacial dislocations by considering the coarsening mechanism of the laths.Moreover,the evolution behavior of backstress caused by dislocation pile up at the block boundary has been considered.Then,a hierarchical model based on the elastic-viscoplastic self-consistent(EVPSC)theory is developed,which can realize the scale transition among representative volume element(RVE),prior austenite grains(PAGs)and blocks.According to the proposed model,the effective mechanical responses including the cyclic hysteretic loop and peak stress at different cycles for lath martensitic steel have been theoretically predicted and investigated.
