考虑脱粘的复合材料加筋板屈曲后屈曲及承载能力数值分析

Buckling,post-buckling and collapse analysis of stiffened composite panels with debonding damage

建立了复合材料层合加筋壁板的屈曲后屈曲有限元分析模型。该模型采用界面单元以有效模拟筋条和壁板之间的连接界面,连接界面和复合材料层板分别采用Quads和Hashin失效准则作为失效判据,引入材料刚度退化模型,采用非线性有限元方法,研究了复合材料加筋壁板在压缩载荷下的前后屈曲平衡路径及破坏过程。数值分析结果与实验结果吻合良好,证明了该方法的合理有效性。详细探讨了筋条尺寸及界面单元强度等参数对加筋壁板屈曲后屈曲行为及承载能力的影响规律,研究表明增加筋条截面惯性矩及筋条密度在一定程度上能有效提高加筋板的屈曲载荷与极限强度,筋条密度增加到一定程度会引起结构破坏形式由失稳破坏转变为压缩破坏,界面强度与铺层方式对极限强度有重要影响,界面脱粘是引起加筋板最终破坏的重要因素。

A strength analysis model was presented to study the buckling and post-buckling analysis of stiffened composite panels subjected to compressive loading by using the nonlinear finite element method.In the model,the debond failure of the adhesive between the skin and stiffener was considered by adding cohesive elements between the shell elements.Quads failure criteria and Hashin failure criteria were adopted to identify the occurring of damage events of the cohesive elements and the composite panels,respectively.By using a degradation constitutive model of the mechanical properties,the equilibrium paths,propagation and catastrophic failure of the structure were simulated in details.The calculated values by the model were well agreed with the measured values.Numerical results show the effectiveness of the model.Parametric studies were conducted to study the effects of geometric parameters of stiffeners,adhesive strength and stacking sequences on the buckling load and compressive strength of stiffened composite panels.The results indicate that the increased sectional moment of inertia and number of stiffeners can improve the buckling load and compressive strength.The transition from instability failure to compression failure exists when the especial number of stiffeners is obtained.Interfacial strength and fiber orientation significantly influence the compressive strength.The debonding damage is an important factor leading to the eventually failure.