TESTING COMPOSITE-TO-METAL TUBULAR LAP JOINTS

Procedures were developed to fabricate, nondestructively evaluate, and mechanically test composite-to-metal tubular joints. The axially load ed tubular lap joint specimen consisted of two metal tubes bonded with in each end of a fiberglass composite tube. Joint specimens with both tapered and untapered aluminum adherends and a plain weave E-glass/epo xy composite were tested in tension, compression, and flexure. Other s pecimens with tapered and untapered steel adherends and a triaxially r einforced E-glass/epoxy composite were tested in tension and compressi on. Test results include joint strength and failure mode data. A finit e element analysis (FEA) of the axially loaded joints explains the eff ect of adherend geometry and material properties on measured joint str ength. The flexural specimen was also analyzed; calculated surface str ains are in good agreement with measured values, and joint failure occ urs in the region of calculated peak peel stress.