Bending,Buckling And Vibration Characteristics Of Porous Functionally Graded Plates On Elastic Foundation

In the preparation process of functionally graded materials,two or more materials with different properties are selected according to the requirements of use to continuously control the composition and structure of the materials,so that and organization of the interface show continuous changes,therefore the materials have excellent physical and mechanical properties.At the same time,according to the needs of modern architecture,civil engineering,aerospace and other engineering structures,the spatial distribution law of each component material can be changed to optimize the internal stress distribution of the structure.It can reduce or avoid the phenomena of delamination damage or germination crack due to stress concentration of the material components,and meet the requirements of the application environment.Therefore,it is of great theoretical and applied value to the study of structural mechanical properties of functionally graded material under complex environment and composite loads.This paper focuses on the static and dynamic characteristics of porous metal/ceramics sigmoid functionally graded material(S-FGM)plates on Pasternak elastic foundations.The research work mainly includes:(1)Pore is a common defect in functionally graded materials,and the pore volume in the material model can not be ignored.However,the modified Voigt model proposed by predecessors is insufficient to approximate the physical parameters of functionally graded materials.In this paper,the pore volume is included in the total volume of the plate.The mass fractions of component materials are used to calculate the corresponding volume fractions.The effective material properties of functionally graded materials with evenly and unevenly distributed porosities are estimated.(2)Based on the composite thin plate theory,the elastic mechanics model of S-FGM plates with voids on elastic foundation under complex load is established.The deflection of simply supported and fixed supported plates on four sides is obtained by Galerkin method.The influence of voids,elastic foundation parameters,in-plane preloading and other factors on plate bending deformation is discussed Galerkin method and Bolotin method are used to solve the buckling problem of S-FGM plates under the cyclic dynamic load of axial compression.The influence of factors such as porosity,elastic foundation and material component index on the critical buckling load and unstable region of S-FGM plates is discussed.(4)the free vibration and forced vibration characteristics of S-FGM plates on elastic foundation under complex load are studied.Based on the theoretical methods and research problems used in this paper,thecorresponding numerical program package is compiled by computer language,which provides a large number of practical and reliable calculation and analysis results for the construction of S-FGM plates components in related engineering applications,and has certain guiding significance for the actual engineering structure design.The results show that when designing and manufacturing S-FGM plates components or apply S-FGM plates components in engineering,we should pay attention to the factors such as the Pasternak elastic foundation,complex load and boundary conditions,which have important influence on the bending deformation,buckling critical load,unstable region,natural vibration frequency and dynamic response of the plate.We should analyze it according to the engineering environment,and though the optimization of the length-width ratio,material quality component index to achieve the engineering material safety and stability requirements.In addition,the influence of porosity on the macroscopic mechanical behavior of the plate is relatively complex,which is not only related to the size and distribution form of porosity,but also related to the mass composition of the material,the parameters of elastic foundation and in-plane pre-loading force,which can not be ignored.