复合材料工字梁铺层结构设计及强度研究
Laminate Structure Design and Strength Analysis of I-beam Composite

根据复合材料层合工字梁的结构特点,基于经典层合板理论和最大应力强度准则,用MATLAB软件编程设计了复合材料工字梁缘条和腹板的铺层结构。建立了基于工艺的3种工字梁铺层结构有限元模型,分析了静载荷作用下3种铺层结构的应力状态。给出了典型铺层的应力云图。计算了复合材料层合结构材料主方向应力,使用最大应力强度准则,给出了线性状态下3种不同铺层结构工字梁的极限载荷。有限元分析结果与经典层合板理论计算结果进行了对比。分析表明:1) 工字梁铺层采用内C形连接和L形连接时极限载荷高于理论设计载荷,外C形连接的极限载荷低于理论值,3种铺层方式极限载荷误差都在9%以内,与理论值基本吻合;2) 有限元分析结果显示初始损伤均发生在工字梁下缘条45°铺层中,损伤模式为基体断裂;3) 工字梁结构极限载荷主要取决于基体强度;4) 工字梁发生破坏的截面位于其固支端;5) 所建立的基于经典层合板理论的工字梁设计方法和工字梁有限元分析模型是正确可靠的。
The laminate structure of an I-beam with strips and web is designed based on the classic laminate theory and the strength criterion of maximum stress. The MATLAB software programming is used and the characteristics of I-beam are considered in the design process. Three finite element models of the I-beam composite with different laminate structures are constructed based on the manufacture process. The stress analysis of the three different laminate I-beam composite is carried out. The stress distributions of some representative layers are given. The stresses of material principal directions are calculated. The ultimate loads of the three laminate I-beams composite are determinated based on the strength criterion of maximum stress on condition that the I-beams composite is in linear state. The results of finite element analysis are compared with that of classic laminate theory. It is showed that: 1) the ultimate loads of the I-beams composite of inner C connection and L connection are higher than the theoretical load; the ultimate load of the I-beam composite of outer C connection is lower than the theoretical load; the relative errors of the three ultimate loads are all smaller than 9% which means the finite element results fit well with the theoretical ultimate load; 2) the initial damages of the I-beams are all occurred in the 45° layer on the lower strips. The damage mode is matrix fracture; 3) the ultimate load of I-beam composite is mainly determined by the strength of the matrix; 4) the damage position is in the cross-section of the fixed end; 5) the design method of I-beam laminate composite based on classic laminate theory and the finite element models of composite I-beam composite built in this paper are reasonable and reliable