Mechanical performance of adhesively bonded carbon fiber reinforced boron-modified phenolic resin plastic-titanium single-lap joints at high temperature

This article characterized the mechanical performance and failure mode of single-lap joints (SLJs) of carbon fiber reinforced boron-modified phenolic resin plastic (CF/BPR) and TC4 titanium alloy by quasi-static tensile tests at four temperatures (25, 100, 175, and 250(degrees)C). The experimental results indicated that the shear strength of SLJs is 10.8 MPa at 25(degrees)C, which experiences monotonic drop to 80%, 42.6%, and 18.5% with temperature increase from 100 to 175(degrees)C, and to 250(degrees)C, respectively. Additionally, there was a transformation in the failure mode from composite material failure to cohesive failure in the adhesive along with the temperature increase. The intralaminar elasticities of CF/BPR were predicted using representative volume element (RVE), and the mechanical properties of three types of bondlines (i.e., the interlamination, interface of CF/BPR and the epoxy adhesive layer) were determined by both experiment and predictive methods. A finite element model taking into account the intralaminar damage of CF/BPR and the cohesive behavior of three bondlines was established. The simulated results showed good consistency with the experimental data for failure prediction, and the mechanical performance and damage propagation of SLJs at different temperatures were discussed. This research provides reference for the design and manufacture of high-temperature bonded structures.