Three-dimensional finite element analysis of single-bolt, single-lap composite bolted joints: Part II - Effects of bolt-hole clearance

Three-dimensional finite element models have been developed to study the effects of bolt-hole clearance on the mechanical behaviour of bolted composite (graphite/epoxy) joints. In Part I of this two-part paper, the model was developed in the finite element code MSC.Marc and validated against experiments and other finite element solutions. In this second part of the paper, results from the model showing the effects of clearance in single-lap, single-bolt joints are presented and compared with experimental results. Both quasi-isotropic and zero-dominated lay-ups are studied. It is shown that increased clearance leads to increased bolt rotation, decreased bolt-hole contact area, and decreased joint stiffness. In single-lap joints, clearance is shown to cause three-dimensional variations in the stress distribution in the laminate, and these variations are also dependent on the lay-up; the radial and tangential stresses in each ply are shown to illustrate this point. Finally, a prediction of the failure onset load using Hashin's failure criteria is given and the results are compared with experimental results.