THE EFFECT OF TEMPERATURE ON BEARING STRENGTH OF CFRP BOLTED JOINT WITH WASHER CONSTRAINING

Effects of temperature on the bearing strength of a CF/Epoxy quasi-isotropic laminate bolted joint are investigated experimentally. The material system is CF/Epoxy T800H/#3631 with stacking sequence of [0/45/-45/90]_<3S>. In this study, a semi-circular notched specimen is chosen and loaded in compression instead of a well-known double lap joint. This method has advantages in material cost and simplicity of its damage mode. A bolted joint with the washer constraint is loaded at 25, 150 and —100℃. Moreover, the cross section of bearing damage zone is observed with an optical microscope after polishing. The results of load-displacement response show a stable manner of damage propagation and no catastrophic load drop for all temperature cases, as compared with pinned joint without any lateral constraint. At 150℃, the lower endurance limit of load appears than 25 and —100℃ cases. From microscopic observation, it is revealed that the initiation and increase of kinking failure of a 0 ° lamina is corresponding to the effective damage initiation of bolted joint and damage evolution, respectively.