Mixed Mode Delamination Growth of Multidirectional Composite Laminates under Fatigue Loading
Fatigue Delamination growth of multidirectional laminates with 45°/-45° fracture interface was experimentally studied.Delamination tests under three mixedⅠ/Ⅱ mode ratios were carried out via mixed mode bending test apparatus.Significant R-curve effects on the fatigue crack growth rates and thresholds due to fiber bridging and crack branching were observed,which make the traditional Paris Law unsuitable.In this paper,a formerly developed modified Paris Law with the normalized strain energy release rate as the fracture goveming parameter is investigated again.The results from the multidirectional delamination tests fit the modified Paris Law very well,and hence have validated it by experiments.Moreover,the thresholds normalized to delamination resistance were utilized to evaluate the critical fatigue crack growth conditions.By the combination of test data for both 0°/5° and 90°/90° laminates,an interface-independent normalized threshold was proposed,which was found linearly decreasing with mode mixture ratios.
Composites R-curves delamination fatigue crack growth
Peng Lei Xu Jifeng Zhang Jianyu Zhao Libin
Beijing Aeronautical Science & Technology Research Institute, Beijing, 100083, China School of Astronautics, Beihang University, Beijing, 100191, China
国际会议
上海
英文
275-275
2012-10-19（万方平台首次上网日期，不代表论文的发表时间）