ABSTRACT

In order to ensure structural integrity in such applications of composites materials, it is important to understand the material behaviour under mechanical loadings and predict correctly its responses. In this paper, the authors perform several three-point bending tests on a typical stacking sequences used in composite structures. Inspection techniques involving a digital microscope are used to study the successive failures and the effect of the thickness ratio (l h⁻¹) on nonlinear behaviour. It was found that successive failures depend on the stacking sequence where the orthogonal sequences have a significant effect on the delamination between the plies. To describe the nonlinear behaviour observed, Von-Karman’s large deflection theory and classical plate theory (CPT) are employed in the formulation of analytical modelling used in this work. The Riccati equation obtained leads to predict the experimental nonlinear curves with good accuracy. However, a slight dispersion between the experimental and analytical curves less than 11% was observed at large deflection.

摘要

为了确保复合材料在此类应用中的结构完整性，了解材料在机械载荷下的行为并正确预测其响应非常重要。在本文中，作者对复合结构中使用的典型堆叠序列进行了多次三点弯曲测试。涉及数字显微镜的检查技术用于研究连续故障和厚度比 (l h ^-1) 关于非线性行为。发现连续失效取决于堆叠顺序，其中正交顺序对层之间的分层有显着影响。为了描述观察到的非线性行为，Von-Karman 的大挠度理论和经典板理论 (CPT) 用于制定本工作中使用的分析模型。得到的 Riccati 方程可以很好地预测实验非线性曲线。然而，在大挠度下观察到实验曲线和分析曲线之间的轻微偏差小于 11%。