基于图乘法大吨位门式起重机跨中挠度预测的研究
Deflection Prediction for Large Tonnage Gantry Crane Girder Midspan Base on Diagram Multiplication Method

门式起重机承受额定载荷时主梁跨中的下挠值是门式起重机整机试验的最重要检测指标。对于大吨位门式起重机整机实验时,实验砝码现场准备往往十分困难,甚至无法进行整机实验检验。针对门架结构考虑了支腿弯矩对主梁挠度影响的情况,推导出集中载荷在主梁L/2、L/3、L/4处作用时的挠曲线方程,通过测量小载荷分别在L/2、L/3、L/4处作用的主梁下挠值,求得主梁和两侧支腿的实际惯性矩,从而可以预测门式起重机额定载荷时主梁的下挠度。主梁三位置小载荷实验法为预测大吨位门架结构主梁挠度提供了实用有效的方法。
The deflection value of gantry crane girder under rated load is the most important inspection index in the overall test. For large tonnage gantry crane, it is often very difficult to prepare the experimental weight on site of the overall test or even impossible to perform the test. In this study, the girder deflection curve equation considering the effects of the leg bending moment on the girder deflection is deduced with the concentrated load applying to the position of L/2、L/3、L/4 of the girder. The girder deflection value can be obtained under small load at the position of L/2、L/3、L/4 of the girde, and the actual inertia moment of the girder and the two side legs can be obtained. In this way, the deflection of the large tonnage gantry crane is predicted through the data of the three-position method in the small load test. The three-position small load test method provides a practical and effective method for the prediction of the girder deflection of large tonnage gantry structure