Distribution des contraintes dans les assemblages collés :

Abstract

We have studied the agreement between theoretical computations and experimental results of surface strains of bonded joints of two types : tenon and mortise, and single-lap joints, for different lengths of the lap. For instance, with the single-lap joint, we have tested four lengths of the overlap from 14 mm to 88 mm. Surface strains are measured by an extensometrical method with electrical gauges, when the specimen is loaded in uniaxial traction on a universal testing machine. Experimental results and computations made by an improved method like the asymptotic expansion method agree, but only if the global traction load applied on the specimen is low, or if the overlap in respect with the others dimensions of the section of test specimen is long. In these joints, effectively, stress fields are disrupted near the butts and become very difficult to compute. Actually, near the ends of the overlap, stresses can reach high limits with only low global load applied on the test specimen. With a short length of the overlap, linear behaviour disappears almost totally because of a strong interaction of the two perturbed fields. On the contrary, with a high length of overlap, stress fields become linear on the major part of the overlap , even with a high tensile load applied on the specimen. So, the length of the overlap has a great effect on the linear behaviour of the joint.