Effects of Temperature on the Bearing Strength of CF/Epoxy Pinned Joints

Abstract

Pinned joint bearing tests are conducted at room temperature (25°C) and at high (150°C) and low (-100°C) temperatures for CF/epoxy quasi-isotropic laminates cured at 180°C with two stacking sequences, namely, [0/45/-45/90]3S and [90/-45/45/0]3S. Then, the evolution of microscopic damage as a function of load is examined by using an optical microscope. This article presents an original set of experimental data on the bearing strength of CF/epoxy pinned joints at high and low temperatures, as well as room temperature, while the previous studies did not cover the wide range of temperatures. Moreover, a technique for dynamically monitoring the load is developed to obtain the damage at the maximum load. The critical damage has not been distinguished from the secondary ones in the previous literature. It is found that the bearing failure of a pinned joint is composed of various damages depending on environmental temperatures; further, the strength of the pinned joint is closely related to the compressive kinking failure of all the inner 0° layers. Other characteristic features of the damage evolution at each temperature are discussed in detail.