Numerical method to assess the stress state and gradients induced by thermo-oxidation in adhesively bonded joints for aircraft engine applications

This paper presents a finite element numerical method to assess the stress state and gradients induced by thermooxidative ageing in Ti/epoxy/Ti adhesively bonded joints for aircraft engine applications. The method is dealing with couplings between thermal, chemistry and mechanics occurring during high-temperature ageing of the joint, taking into account post-curing stresses, and under mechanical loading. Calculations are carried out on a classical single lap joint configuration. An assessment of the stress state and the thermo-oxidation induced gradients at each step of the ageing process is carried out. It is shown that the stress state within the adhesive results from the superposition of several physical fields and is strongly affected by the thermo-oxidation gradients. Moreover, post-curing stresses cannot be neglected when compared to the adhesive yield stress. Numerical analyses are of paramount importance to assess the complex stress fields related to multiphysics couplings and for joint design.