Investigation on impact damage evolution under fatigue load and shear-after-impact-fatigue (SAIF) behaviors of stiffened composite panels

摘要

Experimental investigation on impact damage evolution under fatigue load and shear-after-impact-fatigue (SAIF) behaviors of stiffened composite panels were conducted in this paper. BVID was introduced into stiffened composite panels at a typical position. Damage areas, in-plane dimensions, dent depths were measured and relationships among the three parameters were determined by plane surface function. All fatigue specimens survived after 10~6 cycles at the given fatigue load level and the impact damage did not deteriorate or enlarge during fatigue loading. Then SAI (shear-after-impact) and SAIF experiments were conducted with a comparison of shear on virgin specimens. Buckling/failure modes of virgin, impact and impact-fatigue specimens were obtained. Buckling/failure load of impact specimens decreased by 17% and 16% compared to that of virgin specimens respectively. Additionally, fatigue load led a further 4.3% and 6.6% drop in buckling/failure load of impact-fatigue specimens compared to that of pure-impact specimens, although the impact damage area did not deteriorate or enlarge during and after the fatigue treatment.