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为研究钉孔过盈配合情况和紧固件预紧力及二者混合作用对复合材料连接强度的影响及其机制,提出了一种基于试验验证的有限元方法,在有限元模拟结果与两组不同配合复合材料与钛合金单剪双钉连接拉伸试验吻合良好的基础上,进一步模拟6种不同螺栓预紧力和7种不同钉孔配合模式的组合,共42种不同情况的结构承载能力。通过对模拟结果的分析发现:一定的干涉配合值和预紧力虽然可能导致钉孔周围在受载较小时提前出现较小破坏,但在载荷较大时反而可以改善孔周的接触条件,从而减小孔周的纤维破坏范围,并最终提高连接结构的破坏载荷。而且钉孔配合情况和螺栓预紧力对连接结构承载能力会相互影响,即在不同钉孔配合情况下所得到的紧固件预紧力优化值会有所不同,反之亦然。因此在进行复合材料机械连接结构承载能力优化时,必须同时考虑不同参数的影响,才能获得最优的结构设计。
In order to study the influence of nail interference fit, fastener pretightening force and the effect of the mixture on the joint strength of the composite and its mechanism, a finite element method based on experimental verification is proposed. The results of finite element simulation and two Group of different with composite materials and titanium single-shear double nail connection tensile test in good agreement, based on the further simulation of six different bolt preload and seven different nail hole pattern with a combination of 42 different situations, the structure of the bearing ability. Through the analysis of the simulation results, it is found that: although a certain interference fit value and preload force may lead to smaller damage around the nail hole ahead of the smaller load, the contact condition at the hole circumference can be improved at a relatively large load Reduce the perimeter of the fiber damage range, and ultimately improve the connection structure of the destructive load. In addition, the bolt-hole fit and the bolt pre-tightening force affect the bearing capacity of the connection structure, that is, the optimized value of the fastener pre-tightening force will be different under different nail-hole mating conditions, and vice versa. Therefore, when carrying out the optimization of bearing capacity of the mechanical connection structure of composite materials, the influence of different parameters must be taken into consideration in order to obtain the optimal structural design.