Applications of the Refined Zigzag Theorem (RZT) to exact solutions of cracked-sandwich-beam and composite beam with functionally graded materials

Abstract

In this thesis the refined zigzag theory is used to solve the deflections and stresses of composite sandwich beam According to the configurations of the sandwich beam two parts are included in this study In the first part the cracked sandwich beam (CSB) is investigated by using the Refined Zigzag Theory (RZT) To solve the displacements stresses compliance and energy release reates the continuity conditions at the crack tip and the boundary conditions are derived By comparing the results between the theroretical predictions and finite element computations the solutions by RZT are more accurate than those by FSDT (First-order Shear Deformation Theory) In the present study parameters such as elastic modulus shear modulus layer thickness are considered to investigate their effects on the energy release rates of the CSB In the second part the RZT is extended to investigated the sandwich beam with functionally graded material Various boundary conditions loading conditions and spacial distribution models are considered to investigated their effects on the FGM sandwich beam It reveals that the solutions by RZT agree very much with those by FEM and has low computational resources Material properties equation in thickness direction and the effect of isotropic or orthotropic materials In general FGM is an isotropic material Although FGM with orthotropic material has not developed on the market it is expected that the numerical simulation results for FGM with orthotropic material presented of this paper will be applied to this new material in the future

Date of Award	2019
Original language	English
Supervisor	Chung-De Chen (Supervisor)