Study On Tensile And Damage Behaviour Of Plain Weave Ceramic Matrix Composites

In the past 30 years,great efforts have been made to study the mechanical behavior and damage of ceramic matrix composites(CMCs).Nowadays the majority of studies focus on textile structure CMCs,which has excellent integral performance.Due to the complicated topology of mesostructured and large amount of internal defects of textile CMCs,it is still a challenge to accurately analyse and predict their mechanical behavior.Further investigations are certainly needed to reveal the mechanical behavior of CMCs,and therefore the dissertation carried out a study on tensile property and damageBased on experimental data,the current work employed numerical and closed-form methods to study the tensile and damage behavior of CMCs materials and an open-hole specimen at the scales of fibre tows,unit cells,and laminates.Firstly,at the unit cell scale,a finite element model has been created by using the domain decomposition method,in which,the nonlinear material properties of fiber tows caused by strain-induced damage are taken into account by coding a user defined subroutine.The stress-strain response of a unit cell model under uniaxial tension has been predicted.The simulation results have a good correlation with the experimental data.The effects of plain weave mesostructured on the material’s tensile behavior are addressed.Secondly,at the fibre tow scale,a closed-form approach is used to predict the tensile stress-strain response of a unidirectional tow and a 0°/90° laminate.On the basis of the finite element results and test data,the closed-form method is extended to analyse the tensile behavior of a plain weave CMC,and the close-form results agree well with the test data.Finally,at the laminate scale,the finite element model of an open-hole specimen is developed,in which,the Tsai-Wu failure criterion and nonlinear material properties are considered by using a user defined subroutine.The fidelity of the model is verified by comparing the finite element result with the experimental data.