边界元法计算复合材料的双向拉伸强度

Calculation for biaxial tensile strength of composite materials using boundary element method

采用边界元法,从理论上分析了交织玻璃纤维增强复合材料双向拉伸强度特性。对双向加载的十字型试样,建立了边界元模型,编写了计算程序,获得了材料双向拉伸强度的数值解;同时,建立了有限元模型,进行了对比分析。对材料十字型试样进行了双向拉伸试验,获得不同载荷比下的双向拉伸强度。理论分析和试验结果表明,边界元法理论结果与有限元结果及试验结果均具有较好的一致性,可利用边界元法研究复合材料双向拉伸性能;边界元法在计算效率上优于有限元方法,计算精度上与之相当;交织玻璃纤维增强复合材料具有明显的双向弱化效应,等双拉加载时,材料的双向拉伸强度(纵向强度)仅为单向拉伸强度的60.5%。

The strength properties of the interwoven glass fiber reinforced composite under biaxial tensile loading were theoreti cally analyzed by means of boundary element method. Based on biaxial loaded cruciform specimen, a boundary element model and program were developed for obtaining the numerical results of the biaxial tensile strength of the material. In the meanwhile, a finite element model was analyzed eontrastively.The experimental tests were performed applying biaxial tensile loads to cruciform speci mens. Biaxial tensile strength of the material was obtained at different loading ratios.The theoretical analysis and experimental results show that the theory of the boundary element method has a better consistency with the finite element results and the experimental re sults.Therefore,the boundary element method can be applicable to the investigation of the biaxial tensile properties of composite. BEM has better computational efficiency than FEM while the calculating accuracy is the same. Moreover, the biaxial weakening of the interwoven fiber reinforced composites is remarkable, and the biaxial tensile strength （longitudinal strength） of the material is only 60.5% of the uniaxial tensile strength at the loading ratio of 1 ： 1.