超低温下层合板复合材料的短梁法层间剪切强度研究

Study on short-beam interlaminar shear strength of glass-cloth/epoxy laminates at low temperatures

采用三维有限元法对超低温下玻璃纤维强化树脂层合板的短梁法层间剪切强度进行了研究 ,通过与二维有限元解析结果的对比 ,分析了试验片三维形状对中性面上剪切应力分布的影响 ;通过三维有限元解析 ,阐明了剪切领域内的剪切应力分布 .数值解析结果表明 ,短梁剪切试验片的最大剪切应力并非在中性面上产生 ,靠近载荷点及支点附近产生较大的局部剪切应力 ;中性面上的剪切应力分布不均匀 ,但中性面上最大剪切应力均匀分布的范围较大 ;基于梁理论的表观层间剪切强度较中性面上的最大剪切应力值低 。

The short-beam shear testing method for determining the interlaminar shear strength of glass-cloth/epoxy laminates at low temperatures was studied using a three-dimensional finite element analysis.The 3-D shear stress distribution was compared with the results of a plane-strain finite element analysis,the effect of the specimens 3-D shape on the mid-plane shear stress distribution was examined and the shear stress distribution is discribed.Numerical analysis demonstrates that the maximum shear stress value of the specimens is not on the mid-plane and high local stresses around the loading point and supporting point is observed,that the shear stress distribution is not uniform on the mid-planes but the maximum shear stress is distributed evenly on a large scale,and the interlaminar shear strength for the beam theory is lower than the maximum shear stress on the mid-plane,a lower value would be given by beam theory._