Large Gantry Crane Lowering Load Test Equivalents

The numbers of bridge and gantry crane is increasing and the scale largeday by day. Limited by the site of the large bridge or gantry crane serve in, thehigh cost of heavy test load loading, there are large amount of energy containsduring the loading process, may lead to terrible accident, so the it is difficult toput to the test of large bridge and gantry crane’s metal structure. For the abovereasons, in this paper advance equivalent drop load method, to fit the objectivelaw among stress displacement with load, and calculate the stress anddisplacement of the crane metal structure under heavy tonnage load by the stressand displacement under small tonnage load. Achieve the equivalent loading testof large bridge and gantry crane metal structure with the test load dropped.First, analysis the relationship between stress displacement and hoistingload, during the working range of structure metal, based on the theory of cranemetal structure design. Establish the method of calculate the stress anddisplacement of the crane structure under heavy load through the test result ofstructure stress and displacement under dropped amount load loading. Andfurthermore, analysis the calculation error, based on the relationship between thetest error and calculation error, rise the way to determine the amount of the loadloading.Second, on there are ideal assumptions in the design theory of cranestructure about the structure model and the boundary conditions, based on thesimilarly theory through test of loading step by step to crane, to demonstrationthe equivalent load test method of large bridge and gantry crane.After that, establish another large crane equivalent load test method basedon the artificial neural network and the similarity theory. Furthermore, analyzedthe calculation error based on artificial neural network. And created a softwareof large crane drop load equivalent test method system use VC++6.0.At last, based on the finite element updating establish a large bridge andgantry crane drop load equivalent test method, and make an analyzed about thecalculation error. Through engineering example, the theoretical calculation results and testdata and calculated results of the proposed method, the rationality of theproposed method was verified. In this paper, equivalent load test method, bysmall tonnage load under the action of structure stress and displacement testvalues fitting calculated values of stress and displacement under large tonnageload, load testing for large bridge gantry crane structure provide a new testmethod and theoretical basis.