Crack Propagation on ESE(T) Specimens Strengthened with CFRP Sheets

摘要

In this paper fatigue tests on side notched steel test specimens strengthened with adhesive bonded fibre reinforced polymer (FRP) sheets are presented. The specimens are subject to crack growth both in the steel and bond line. Influence of the load ratio and initial crack length on the overall endurance and debonding of the laminate was experimentally investigated. Strengthening increased the endurance of specimens up to 6.1 times and a higher load ratio was found to shorten the endurance increase. The growth rate of the debonded zone was unchanged in specimens with long initial crack lengths, thus the laminate was utilized better at any given crack length than in specimens with shorter initial cracks. Using the optical measuring equipment ARAMIS the size and shape of the debonded zone was measured at long crack lengths, proving an increasing debond growth rate close to failure.