Mechanical behavior and failure mechanisms of CFRP and Titanium tubular adhesive lap joints at extreme temperatures

Abstract

In this study, the mechanical behavior and failure mechanisms of thin-walled carbon fiber reinforced polymer (CFRP) and titanium adhesive tubular lap-joints (TLJs) at cold-temperature, room-temperature, and elevated-temperature are investigated. The prediction of TLJ’s performance at extreme temperatures is challenging due to their non-linear behavior and competing damage modes. To better understand their behavior, finite element analysis, static tensile tests, and design of experiments are employed to investigate the competing damage mechanisms within the TLJs, leading to a more detailed damage classification at extreme temperatures. Results show a mixed-mode failure region at elevated-temperature, where TLJs fail by either interlaminar shear or titanium net-section fracture. X-ray micro-computed tomography reveals that the initiation, propagation, and coalescence of delamination at the inserted end of the CFRP are created by shear stresses during deformation of the titanium. By utilizing numerical, experimental, and statistical techniques, this work aims to provide insights into the parameters and damage mechanisms affecting the performance of adhesively bonded thin-walled TLJs at extreme cold and hot temperature conditions.