复合材料层板损伤失效分析

基于连续损伤理论,利用多标量损伤模型,考虑单层板失效前由微裂纹损伤所造成的刚度下降,将Hoffman准则作为复合材料单层板在复杂应力状态下的极限损伤条件,应用该准则对含圆孔复合材料层合板在单向拉伸载荷下的损伤破坏过程进行了数值分析,并与常规(无损伤)失效准则的结果进行了比较.计算表明:损伤引起单层刚度下降,使应力重新分布,加速应力向未损伤层和周围单元转移,从而使应力集中得到缓解,层板的单层破坏载荷明显提高,从而提高层板的极限载荷,提高程度受铺层方式的影响.可见,由损伤引起的刚度下降应在层板失效分析中加以考虑.

Analysis of Damaging Failure of Composite Laminates

Based on progressive damage theory,a non-linear and multi-scale damage model is developed to consider the stiffness reduction caused by micro-crack before the failure of a single lamina.The Hoffman criterion is taken as an ultimate condition for the damage to a single lamina of composite laminate in complex stress state.Then,the criterion is introduced to a numerical analysis made for the damaging failure process of a composite laminate with a hole under unilateral load,and the result of the analysis is compared with that taking conventional or no damage failure criterion.The results indicate that the stress concentration is relaxed due to the reduced stiffness of damaged single lamina which leads the stress to redistribute and accelerates the stress transfer to undamaged laminae and their peripheral elements.It implies that the failure load of a single lamina is improved greatly as well as the ultimate load of the composite laminate.But,the way to laminate will affect the improvability.The analysis reveals that the decreasing stiffness due to damage should be taken into account in the failure analysis of composite laminates.