Experimental and numerical investigations of an asymmetric multi-bolted connection preloaded and subjected to monotonic loads

Abstract The experimental tests of seven-bolted connection with an asymmetric contact area between the joined elements are presented. The research was divided into two stages. In the first one, the connection was preloaded in a three-pass cycle. In the second stage, the connection was loaded with a monotonic alternating force applied at an angle of 30 degrees to the contact surface of the joined elements in order to generate compressive and shear forces in the connection. The tests were carried out with the use of the INSTRON 8850 testing machine. As a result of the research, the courses of forces in the bolts measured with use of resistance strain gauges and the relative displacements between the joined elements measured with an extensometer were shown. In the second part of the paper, the modelling of the connection in the convention of the finite element method is presented. The joined elements were modelled with use of spatial finite elements, and the fasteners – as a hybrid elements made of deformable beams, rigid heads and rigid nuts. The paper is completed with a comparison of the results obtained from the measurements and calculations, on the basis of which conclusions important from the point of view of the FEM analyst were drawn.