In this paper, mechanism of fastened joints is described; numerical analyses and testing calibrations are conducted for the possible simplified finite element simulation approaches of the joints; and the best simplified approach is recommended.
The approaches cover variations of element types and different ways that the joints are connected. The element types include rigid elements, deformable bar elements, solid elements, shell elements and combinations of these element types. The different ways that the joints are connected include connections of one row of nodes, two row of nodes and alternate nodes in the first and second rows. These simplified simulation approaches are numerically evaluated on a joint of two plates connected by a single fastener. The fundamental loads, bending with shear, shear and tension are applied in the numerical analyses. A detailed model including contact and clamp load are analyzed simultaneously to provide “accurate results”.
The typical simplified simulation approaches are calibrated by two physical fatigue tests of a rear chassis frame assembly loaded by a constant reversed cyclic force. The critical fatigue damage area is located at a bolt joint on the rear bumper beam bracket.
The simplified simulation approach of modeled washer with 2.5 times of the plate thickness shows the best results in both the numerical analyses and physical test calibration.