Research On Finite Element Analysis Method Of Pinned Connection Based On Photoelastic Experiment

As an important connection form, pinned connection is widely used in cranes and other types of lifting equipment in the modern steel structure field. It has the advantages of clear force transmission and simple structure. The typical stress states of pinned connection contain the multi-faceted shear of pin and the concentrated compression of hole wall. And its partial structure and internal stress state are very complex. Currently, there are no rules and standards relating to the calculation of pinned connection. Usually, in the design of pinned connection, great strength reserves are chosen to compensate for the lack of calculation accuracy, which cost a certain waste. Therefore, a further study on the load mechanism, stress distribution and design methods of pinned connection is of great significance for guiding engineering design and promoting structural lightweight.In this paper, the typical pinned connection in the crawler crane luffing tension plates was took as the research object. Combined with finite element analysis software ANSYS, the distorted model photoelastic experiment was conducted to study the mechanical behavior of pinned connection and the stress state of tension plates. Firstly, the distorted photoelastic experiment specimen was fabricated based on the photoelastic experimental conditions and the geometric characteristics of the tension plates. Then the photoelastic experiment was designed and completed. Secondly, by combining digital photoelastic software Digital Photoelasticity and data processing software Origin, the experimental bearing stress results were obtained, on which the real constant of ANSYS contact module was set. And then bearing stress setting solution was got that was suitable for the pinned connection of all size and all materials. Finally, theoretical bearing stress formula in the manual was corrected based on the finite element analysis results.The analysis of different loads and different thicknesses of the tension plates showed that: the maximum bearing stress position is not collinear to the load direction, but in the both sides of the load line and, with the increasing of the load, the position migrates outward; in the ANSYS finite element contact module of steel-steel pin connection, the recommended range of the real constant penalty stiffness settings is0.3to0.4, and the default value is0.35, which well matches the photoelastic experiment; the bearing stress formula in Mechanical Design Handbook is proved to be reliable but conservative with the error within3.5percent. Based on the distorted model photoelastic experimental results of pinned connection in the tension plate, this article puts forward a reasonable real constant set of finite element method in ANSYS, and the results can be used as a reference in the designing and checking of pinned connection.