面外载荷下含孔复合材料点阵夹层结构弯曲强度数值计算方法

通过实验手段和有限元方法针对含孔碳纤维增强树脂基复合材料(Carbon Fiber Reinforced Polymer,CFRP)点阵夹层结构在面外载荷作用下的失效模式及其影响因素进行了研究。首先通过实验获得了含孔CFRP点阵夹层结构的失效模式,其次建立了其有限元渐进损伤失效分析模型,基于该模型对开孔形状、开孔率及开孔位置对结构弯曲强度的影响进行了探讨。结果表明,当面板较厚时,含孔CFRP点阵夹层结构的主要失效模式为节点脱粘和面板皱曲;有限元计算结果和实验结果吻合较好,极限承载力的误差约为9.1%;当开孔率φ1.3%时,CFRP点阵夹层结构的弯曲承载能力与开孔形状基本无关;当开孔率1.3%≤φ8.5%时,含圆形孔夹层结构的弯曲承载能力较大;当开孔率φ8.5%时,含方孔夹层结构的弯曲承载能力较大;当开孔位于点阵夹层结构的几何中心或边缘时,对弯曲承载能力影响较大。

Numerical method for bending strength of composite lattice sandwich structure containing hole under external load

Failure modes and its influence factors under external load of CFRP lattice sandwich structure containing hole were investigated by experiment and finite element method. Failure modes were revealed firstly by experiment. Then a progressive damage failure model was established. Based on this model, influences of hole shape, opening rate and hole position on bending strength of CFRP lattice sandwich structure were discussed. The results show that when the panel is thicker, the main failure modes of the lattice sandwich structure containing hole are panel wrinkling and node debonding. The numerical result matches the experiment well with the error of the ultimate load of 9.1%. When the opening rate φ is less than 1.3%, the bending bearing capacity of CFRP lattice sandwich structure is uncorrelated with hole shape. When φ is from 1.3% to 8.5%, the bending bearing capacity of sandwich structure containing a rounded hole is larger. In other cases, the bending bearing capacity of sandwich structure containing a quadrate hole is larger. The holes located at the geometric center or near edges of the CFRP lattice sandwich structure have greater influence on the bending bearing capacity.