A STRESS-ANALYSIS OF A MECHANICAL JOINT FOR CARBON COMPOSITE RODS

The high axial tensile strength and the low transverse strength of pul truded composite rods present some unique problems in testing with con ventional grips. The high transverse compressive forces required in th e conventional method of gripping tent to crush the rod, thereby causi ng premature failure. Design guidelines for an end tab grip adapter us ed in tensile testing of pultruded composite rods can be found in ASTM standard D3916-84. Although this standard is applicable to glass fibe r reinforced rods, it is inadequate for high-strength composites becau se of slip. It is therefore necessary to develop and characterize a ne w tension jig for high-strength fiber composite rods such as graphite fiber composites. The present paper presents results from a two-dimens ional nonlinear finite element analysis to characterize the contact pr essure and stress distributions at the interfaces and maximum axial lo ad available in the jig developed.