Failure analysis and behaviour of titanium alloy metal matrix composite bolted joints

Pin-loaded hole coupons with tapered geometry were tested to examine the failure behaviour of titanium alloy metal matrix composite (MMC) bolted joints at room temperature and 650°C. The average failure load at 650°C decreased almost to half of the average failure load at room temperature. Additional tests were also carried out at room temperature to investigate different methods to extend the life of the joint. A polyester film was applied around the hole on one face of the specimen, which consequently changed the failure mode and post-failure response of the specimen. Finite element (FE) analyses were performed to predict the behaviour of titanium MMC bolted joints. Failure loads were predicted by solving a boundary value problem representing a single lap bolted joint. A modified concentric cylinders model (CCM) was employed to predict the effective properties used in the FE and failure analyses. Good agreement was shown between the experimental results and the predictions.