Random Earthquake Response And Reliability Analysis Of Gantry Crane

Gantry crane is easy to use with stable structure, for which it becomes the most common lifting equipment with broad uses. China is a seismically active country, and the losses and damages caused by the collapse of the cranes during earthquake accidents can not be ignored. At present, the seismic design of the crane in China remains in static analysis phase, the current "Crane Design Manual" reduces seismic load to the equivalent concentrated static load. Since the strong randomness of both the seismic dynamic load and earthquake’s occurance, in order to ensure the seismic safety of the gantry crane structure, it is necessary to apply random seismic response analysis and dynamic reliability analysis on gantry crane.The main contents are as follows:1. Use ANSYS to apply static analysis on gantry crane. Create the finite element model of a large-span gantry crane, according to the requirements of "Design rules for cranes" to check gantry crane’s structure in rigidity condition, strength conditions and seismic conditions.2. Use ANSYS to apply modal analysis and multi-dimensional&consistent seismic response spectrum analysis on gantry crane. Modal analysis results contain front 10 steps mode frequency, shape and participation factor of mode. Establish gantry carne seismic response spectrum analysis dynamic equation, apply seismic response spectrum analysis on grantry crane in five input conditions and write the corresponding APDL command. Nodes of flexible leg and main beam are respectively selected to compare displacement and stress results in different input conditions.3. Introduce the theory of gantry crane random seismic response analysis and several different seismic models. Base on probability theory and random vibration theory to deduce the dynamic equation of gantry carne structure system under multi-dimensional stationary random seismic response and solve the equation.4. Use ANSYS to apply multi-dimensional& multi-support random seismic response analysis on grantry crane. Choose DU Xiu-li-Chen Houqun seismic model and select the appropriate parameters to apply random seismic response analysis on grantry crane in five input conditions and write the corresponding APDL command. Nodes of flexible leg and main beam are respectively selected to compare displacement and stress results in different input conditions, and finally compare the results of seismic response spectrum analysis and random seismic response analysis respectively.5. Gantry crane random dynamic reliability analysis. Base on first passage failure theory and Poisson assumption of cross process to deduce the formula to calculate ganrtry crane’s reliability. Select the nodes with maximum SD of Y direction (the vertical direction) displacement result in main beam as control point, base on MATLAB and the results of random seismic analysis to calculate the seismic dynamic reliability of grantry crane in five input condicions.The results of this study can not only provide a reference for random seismic response analysis of gantry crane, but also provide some theoretical guidance for the seismic reliability design of gantry carne structure.