Effects of variable clearance in multi-bolt composite joints

In this paper, the effects of variable clearance in multi-bolt, composite joints on load distribution, quasi-static strength and fatigue life have been studied experimentally. Both single-lap and double-lap configurations have been examined. The clearances examined ranged from neat-fit to clearances slightly larger than those allowed in the aircraft industry. Clearance has been found to have major effects on the load distribution in bolted joints, but negligible effect on ultimate strength. However, clearance had significant effects on initial failures such as bearing failure in one hole. A clearance-fit hole has been found to reduce fatigue life. The number of cycles to initiation of hole elongation under fatigue was particularly sensitive to the presence of a loose-fit hole.