Development of simplified finite-element model using interpolation rigid-body element for bolted joint of attachment rail in rolling stock

Since many bolted connections are used in rolling stock, it is necessary to improve the prediction accuracy of stress distribution of the connections in order to reduce the weight and improve the reliability of the structure. In addition, it is important to balance accuracy and reduction computation time by using low-dimensional elements such as shell and beam in the analysis of large structures such as rolling stock. The purpose of this study is to verify the practicality of the simplified finite element modeling method for bolted joints of attachment rails in rolling stock composed of aluminium alloy hollow extrusions, which was proposed in the previous study. In order to understand the behavior of the joints, static load tests were conducted on a full-scale specimen with four attachment rail bolt joints, in which combined tensile, shear, and bending loads were applied, and the strains in the vicinity of the joints were obtained. Simplified modeling using shells, beams, and RBE3 elements was also performed on the specimen. The results showed that the deformation mode of the attachment rail could be reproduced by the simplified model. In addition, the results of the simplified model agreed with the test results in terms of the strain distribution at the nominal section of surface plate and the observed maximum error was 5.0%. It was also confirmed that the simplified model could reproduce the local strain distribution in the extrusion direction and the transverse direction of the extrusion of the attachment rail near the bolted joint. Therefore, we concluded that this simplified modeling method could be practically applied to modeling of bolted joints of attachment rails in actual underfloor equipment of vehicles.