The Hygro-Thermo-Mechanical Response Of Laminated Composite And Functionally Graded Strucure

Reddy-type higher-order theory has been widely used in laminated composite structures and functionally graded material structure(FGMs)analysis.However,the theory neglects transverse normal thermal strain,so it will encounter difficulties for structure subjected to hygro-thermo-mechanical loading.To improve the accuracy of Reddy theory,a Reddy-type higher-order theory considering transverse normal hygrothermal strain has been proposed in this paper.Then a C~O-type Reddy’s theory including the transverse normal hygrothermal strain is proposed to eliminate the first derivatives of transverse displacement.Thus it is convenient to construct a higher-order element.Although transverse normal thermal strain has been taken into account,the number of displacement parameters has not increased.In terms of Reddy’s theory including the transverse normal hygrothermal strain,the hygro-thermo-mechanical response of the laminated composite plate and functionally graded beam has been analyzed,the effect of different loadings,side-to-thickness ratio and volume fraction on stress and displacement has been also studied.An eight-node quadrilateral isoparametric element was constructed based on the C~O-type Reddy’s theory including the transverse normal hygrothermal strain.The analytical solution and the finite element results of the FGM plate subjected to hygrothermal loading are obtained respectively.Numerical results showed that the present model can accurately calculate the hygro-thermo-mechanical response of laminated composite structures and functionally graded material structure compared to other theories neglected transverse normal thermal strain.The convergence of the constructed element is good with mesh refinement.