Failure Analysis of Composite Material Under External Hydrostatic Pressure: A Nonlinear Approach

Abstract

This current study reports on comparison of nonlinear buckling behaviour of composite material under external hydrostatic pressure using finite element concept. Triaxial failure analysis has been employed at micro level to predict the damage behaviour and failure envelopes of polymer carbon-fiber reinforced composite involving thickness stresses. In addition, a buckling pressure equation based on ASME codes customized to IM7/8552 composite material was also presented. Finite element analysis using solid 3D shell element 190 with finite strain for IM7/8552 composite material have been performed in order investigate the validity of finite element method. Pre and post failure material nonlinearity in composite material has been discussed. The scope of present study is directed towards proposing the nonlinear constituent failure criteria and inelastic buckling behaviour of composite material at hydrostatic pressure. Furthermore, theoretical studies were done in conjunction with analytical studies to verify numerical analysis. It was found that IM7/8552 has failed due to its material nonlinearity having orthotropic properties. Optimal and accurate convergence in solution was observed and finite element analysis results are validated successfully. It can be concluded that there was significant increase in the mechanical properties as a function of hydrostatic pressure ranging from 0.13 to 1.20%. Allowable buckling pressure is anticipated by thickness to diameter ratio focuses geometric nonlinearity in material. The ASME equation and Windenburg equation (ABS) reveals in good prediction of design factor (∼ 3.5) for allowable buckling pressure. The progressive damage analysis showed finite element analysis and theoretical results are in agreement. The further scope of this study involves in development in failure constituent criteria with new damage analysis incorporating pressure and low temperature effects.