Mechanical Properties of RTM-made Composite Cross-joints

Tension and shear tests are carried out on composite cross-joints, produced by resin transfer moulding (RTM), stitch-RTM and cobonding techniques separately, to investigate the influences of different production methods on their mechanical properties and their failure mechanism. It is concluded from test results that, in terms of mechanical properties, the RTM-made cross-joint holds superiority over other two, and both stitch-RTM and cobonding methods have significant adverse effects on mechanical properties. Experimental observation and finite element (FE) numerical simulation show that the delamination first takes place at the upper triangle-like resin-rich zone of joints, then propagates along the interface between the zone and the curved webs/flanges to the bottom plate, and grows along the horizontal bottom plate till failure of the joint accurs at last. Results demonstrate that there is a good agreement between the FE model and the tests.