基于梯度型褶皱缺陷细观力学模型的响应预测和激光剪切散斑干涉测量

Response prediction based on meso-mechanical model of graded wrinkle defects and shearography measurement

  • 摘要: 针对碳纤维增强树脂基复合材料(Carbon Fiber-reinforced Polymer, CFRP)中褶皱缺陷的力学响应,提出了一种基于激光剪切散斑干涉的检测方法。首先构建了表征梯度型褶皱缺陷的细观力学模型,采用两步均匀化方法推导了含褶皱缺陷的代表性体积单元等效刚度矩阵,分析褶皱缺陷对层合板试样等效刚度系数影响,通过有限元预测了不同褶皱缺陷参数(铺层顺序、波长λ、振幅A)在不同拉伸载荷条件下的力学响应。其次,基于激光剪切散斑干涉技术开展了褶皱缺陷位移响应实验研究。实验结果表明,在拉伸载荷作用下,褶皱缺陷区域因离面位移梯度变化而产生干涉条纹,通过干涉条纹图处理,得到褶皱缺陷引起的位移场。实验获取的离面位移值与有限元预测结果吻合良好,证实了梯度型褶皱缺陷的细观力学模型在CFRP褶皱缺陷响应分析方面的可靠性。

     

    Abstract: This study proposed a detection method based on shearography for the mechanical response of wrinkle defects in carbon fiber-reinforced resin polymer (CFRP). Firstly, a meso-mechanical model characterizing graded wrinkle defects was constructed. The equivalent stiffness matrix of the representative volume element containing wrinkle defects was derived using a two-step homogenization method, and the effect of graded wrinkles defects on the equivalent stiffness coefficients of laminates was analyzed. Finite element analysis was then employed to predict the mechanical response under different tensile loading conditions for various wrinkle defect parameters (such as ply sequence, wavelength λ, and amplitude A). Secondly, experimental research on wrinkle defects displacement response was conducted using shearography. Experimental results show that under tensile loading, the interference fringes are generated in the wrinkle defects region due to the gradient change in out-of-plane displacement. By processing the interference fringe images, the displacement field caused by wrinkle defects is obtained. The out-of-plane displacement values obtained from experiments match well with the finite element prediction, confirming the reliability of shearography in measuring the response of wrinkle defects in CFRP.

     

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