复合材料层合板多钉连接的紧固件连接柔度

复合材料层合板多钉连接结构中螺栓紧固件连接柔度随钉排数增加而变化。为了阐明多钉连接紧固件连接柔度与单钉连接紧固件连接柔度的差异并建立多钉连接紧固件连接柔度的计算方法，进行了ZT7H/5429复合材料层合板螺栓连接结构拉伸试验和紧固件连接柔度解析求解；研究了旁路载荷对紧固件连接柔度的影响规律并提出了旁路载荷伴随下紧固件连接柔度的计算公式；针对紧固件连接柔度取值与分析模型的相关性，构建了描述钉间层合板柔度偏差的模型适应函数并提出了面向分析模型的紧固件连接柔度修正公式；对1列5钉连接结构进行了钉载计算。结论表明：采用所建立的修正公式对紧固件连接柔度修正后，使得梁-壳有限元模型的钉钉载最大计算误差由16%减小至3%，钉载峰值的计算误差由11%减小至2%，实现了准确且快速的钉载计算，尤其适合大规模复合材料层合板结构钉群连接区的工程应用。

Fastener connection flexibility of multi-bolted joint of composite laminate

The connection flexibility of fasteners varies with the rows of bolts in a multi-bolted joint structure of composite laminates. To study the relationship between the fastener connection flexibility of multi-bolted joints and that of single-bolted joints, and develop the calculation method for predicting the fastener connection flexibility of multi-bolted joints, tensile tests of bolted joints of ZT7H/5429 composite laminates were conducted to calculate the fastener connection flexibility of the multi-bolted joint analytically. The influence of the bypass load on connection flexibility of fasteners was studied, and a formula for calculating the connection flexibility of fasteners accompanied with bypass loads was established. Considering that the value of the connection flexibility of fasteners correlates to the analysis model, model-adaptation functions were proposed to describe the flexibility deviation of the laminates between two bolts and utilized to develop the modeling-oriented formula for correcting the connection flexibility of fasteners. The proposed method was used to analyze the bolt load distribution of the ont-line five-bolt joint. The results show that with the proposed method, the maximum calculation error between the beam-shell model and the three-dimensional solid model can be reduced from 16% to 3%, and the calculation error of peak bolt load is reduced from 11% to 2%. The proposed modification method can help improve and realize accurate and fast calculation of bolt load distribution in the multi-bolted joint, and is especially applicable for the bolt group connection area of large-scale composite laminates.