Analysis of the Active Fence Structure Based on the Analytical Model of Transverse Cantilever Beam Impact

In the process of stream sorting of unit loads, one of the load manipulation methods is scraping with a rotary active fence. During the contact of the fence with the load a dynamic force occurs the value of which should be minimised by the adequately selected fence structure. For that purpose, there have been analysed a few impact models of the fence ( beam) with a load, which involved mostly a plastic and elastic impact with the Hertz local contact model. It turns out that, due to the complexity of the optimisation of such fence, where both a variable cross section of fence and shear stresses must be considered, the analytical impact model between fence and load can considering only the first mode of vibration when the Hertzian contact is taken into account. It results in a considerable overestimation of the maximum impact force. In the plastic impact model, at the time of contact initiation, step change of velocity occur, which excludes a possibility of estimating the impact force. However, it turns out that as for the range of the fence applicability in terms of masses and the scraped load velocity, the model allows for an adequate estimation of the fence deflection. It facilitates minimising the fence mass without exceeding the admissible deflection due to impact.