Mathematical modelling of bridge crane dynamics for the time of non-stationary regimes of working hoist mechanism

Bridge crane is exposed to dynamic loads during its non-stationary operations (acceleration and braking). Analyzing these operations, one can determine unknown impacts on the dynamic behavior of bridge crane. These impacts are taken into consid- eration using selected coefficients inside the dynamic model. Dynamic modelling of a bridge crane in vertical plane is performed in the operation of the hoist mechanism. The dynamic model is obtained using data from a real bridge crane system. Two cases have been analyzed: acceleration of a load freely suspended on the rope when it is lifted and acceleration of a load during the lowering process. Physical quantities that are most important for this research are the values of stress and deformation of main girders. Size of deformation at the middle point of the main crane girder is monitored and analyzed for the above-mentioned two cases. Using the values of maximum de- formation, one also obtains maximum stress values in the supporting construction of the crane.