Seismic Analysis Of Auxiliary Bridge Crane For Nuclear Power

The special crane for nuclear power plant is a kind of special lifting equipment which contains huge energy and is closely related to the safety of nuclear power plant.It will exist in each plant room in nuclear power plant.When the nuclear power plant is subjected to an earthquake,the auxiliary bridge type lifting machine for nuclear power set up on the leg of the building will be more strongly excited because of the amplification effect of the seismic excitation of the floor,which will lead to the derailment and fall of the crane or parts falling off and other accidents.So it is very important to analyze the earthquake resistance of the special crane for nuclear power.It is impossible to predict the occurrence of earthquakes.When the earthquake occurs,the crane may be in any working state.In the design of conventional crane in our country,the description of seismic excitation is not detailed,and the combination of seismic excitation and adverse working conditions is not considered.For the nuclear power crane,such a design method is obviously not thorough,combined with the conventional crane load and load combination,for the nuclear power crane under the seismic excitation of a load combination,and according to the load combination of the working conditions are discussed.The auxiliary bridge crane for nuclear power is a complex system,and its dynamic response is more complex and disordered under earthquake excitation.The complex system is reasonably simplified to a multi-degree-of-freedom system,and the seismic excitation is simplified.The dynamic differential equations are obtained by loading on the system in three dimensional directions.According to the dynamic differential equation,different position of the trolley,different lifting height,lifting weight and other factors will have an impact on the seismic analysis results.For the dynamic response analysis of the auxiliary bridge crane for nuclear power under seismic excitation,the mode decomposition response spectrum method is adopted to improve the analysis efficiency considering the multiple working conditions.The research object of this paper is two auxiliary bridge cranes for nuclear power with inconsistent weight ratio of 10 t and 130 t self-weight lifting,and the analysis software is ANSYS Workbench.Static analysis was carried out to determine the design of the two cranes in accordance with the design requirements.Then modal analysis is carried out to determine the modal frequency of the crane.Finally,a suitable mode combination method was selected to analyze the response spectrum.The seismic analysis results under various working conditions of the crane show that the dynamic response of the crane is the largest when the trolley is in the span of the crane,and the dynamic response decreases as the trolley moves towards the two spans.When the lifting weight is in the upper limit,the inertia force produced by the shaking of the lifting weight has the greatest influence on the crane,and the influence decreases with the decrease of the lifting weight.When the deadweight to lifting ratio changes,the dynamic response of the crane with small deadweight ratio increases less than that of the crane with large deadweight ratio.In this paper,the dynamic response of the special auxiliary bridge crane for nuclear power under seismic excitation is compared and analyzed by means of multiple working conditions and dual models,and the seismic response law of the crane is explored to a certain extent,which has certain reference significance for others to carry out subsequent seismic design calculation of nuclear power crane.