Temperature effects on joint strength and failure modes of hybrid aluminum–composite countersunk bolted joints

Abstract

This paper presents the effects of temperature on the damage initiation and growth in the carbon fiber-reinforced polymer composite laminate of a hybrid aluminum–composite countersunk bolted joints designed for the bearing failure mode. Strain gage measurements conducted using an Instron testing machine coupled to a temperature-controlled chamber together with a detailed three-dimensional finite element model incorporating geometric, material and friction-based full contact nonlinearities are used to investigate the temperature effects on the progressive damage analysis of the orthotropic material model. The progressive damage analysis material model integrates the lamina nonlinear shear deformation, Hashin-type failure criteria and strain-based continuum degradation rules, being developed using the UMAT user subroutine in the MSC Patran-Nastran (MSC Software Corporation) commercial software. The results showed that the temperature effects on damage initiation and failure modes are quite accurately predicted by the progressive damage analysis material model, which proved to be computationally efficient and therefore can predict failure propagation and damage mechanisms. A low temperature increases the limit and ultimate forces and produces net-section failure, while a high temperature favors a bearing failure and even shear-out of the composite adherend of the hybrid aluminum–composite countersunk bolted joint.