基于可靠性的CFRP螺栓连接优化设计方法

螺栓连接是复合材料结构的薄弱环节。因此，螺栓连接部位的设计是先进复合材料结构设计的关键之一。将修正特征曲线方法和随机参数统计模型结合，建立了碳纤维增强复合材料（CFRP）螺栓连接失效载荷的概率分析模型，进而以关键影响参数为设计变量，以可靠度指标为约束，以连接结构质量为设计目标，发展了基于可靠性的CFRP螺栓连接优化设计方法。采用正交试验设计方法建立基于可靠性的螺栓连接优化设计计算方案，优化结果表明:关键影响参数X_C为2 450 MPa、t_ply为0.174 mm、E₁₁为225 GPa时的设计方案为螺栓连接最佳设计方案，该方案使得外载荷为17.5 kN时，螺栓连接可靠度由0.998提高到0.999 999以上，同时使得连接结构的质量下降了6.44%。 

Reliability-based design optimization method of CFRP bolted joints

Bolted joints are the weak points of composite structures. Therefore, the design of bolted joints is one of crucial issues in the design of composite structure. In this paper, a probability analysis model for the failure load of a Carbon Fiber Reinforced Polymer (CFRP) composite bolted joint was built by combining the modified characteristic curve method and the statistical model of random parameters. The key influence parameters were regarded as the design variables, the reliability index was considered as the constraint, and the mass of the joint was the design goal. Accordingly, a reliability-based design optimization method was developed for the CFRP bolted joint. The orthogonal test design method was used to establish the reliability-based optimal design calculation scheme. The optimization results show that, when the key influence parameters X_C is 2 450 MPa, t_ply is 0.174 mm, and E₁₁ is 225 GPa, the best design of the joint is obtained. According to this scheme, when the external load is 17.5 kN, the reliability of the joint is increased from 0.998 to above 0.999 999, and the mass of the joint is reduced by 6.44%.