多钉连接钉载分配特性研究方法

Experimental and numerical study on the pin-load distribution of multiple-bolted joints

利用金属-复合材料层合板紧固件多钉连接件开展拉伸载荷下钉载分配特性的试验和有限元分析研究。试验件为一列三钉单搭接和双搭接连接件。通过应变电测技术获得连接件典型截面应变分布,再间接估算钉载分配比例。建立了试验件二维、三维有限元模型,并计算获得应变和钉载分配结果。对比发现,应变的计算值与实测值吻合,但钉载分配的计算结果与实测结果存在较大偏差。分析表明:基于表面应变测量估计钉载分配的方法不能反映连接件的附加弯矩对多钉钉载分配比例的影响;采用经过应变测量结果验证的有限元模型,通过数值计算确定钉载分配是一种可行的技术途径;而应用简化的板-梁二维有限元模型计算钉载分配可以满足工程精度要求。

Test and finite element analysis were carried out to characterize the pin-load distribution of multiple- bolted metal-to-composite fastener joints. The specimens are the single-lap and double-lap joints with an array of three bolts and subjected to tension loading. The surface strains at certain cross-sections of the metallic plates were measured using the strain gage technique. The pin-load fractions of the multiple bolts were then estimated indirectly using the measured strains. Two and- three dimensional finite element models were also constructed to calculate those strains and the pin- loads. The calculated strains agree well with the measurement, whereas significant difference is observed between the pin load fraction results of both methods. The investigation reveals that the way to determine the pin-load distributions ratios according to the plate surface strains is not able to account for the built-in effects of additional bending moment concurrently with the tension loading. The authors believe that the numerical calculation to estimate the pin-load fractions, based on finite element modeling which has been validated by the surface strain measurement, is a technically feasible approach. The two-dimensional models formed by beam and shell elements are of satisfied accuracy to determine the pin-load distributions.