起重吊钩极限承载力试验

摘要

The ultimate bearing capacity and safety factor of a large lifting hook was determined by the methods of model test and finite element simulation in the present paper.First,larger stress points,known as dangerous points,are obtained by the method of finite element and mechanical analysis.The similarity relation between the real object and model of lifting hook under the concentrated force was derived based on the model test theory.Then a hook model at a ratio of 4:1 to the original hook was manufactured for different loading tests.Synchronous measurement of the strain of dangerous points was made by using electric resistance strain gauges to get the load which made the model to yield.Finally,the actual ultimate strength and the safety factor of the lifting hook was obtained according to similarity relation.The test results indicate that the lifting hook is safe at the rated condition with a safety factor 1.14 and the proposed method can efficiently determine the actual ultimate bearing capacity of the large lifting hook for its safety and reliability.%利用模型试验与数值计算相结合的方法,测定了某大型起重吊钩的极限承载力及其安全系数.首先,通过有限元计算及力学分析得出其在额定工况下的应力较大点,即危险点；然后应用模型试验理论推导了静态集中力作用下吊钩实物与模型的相似关系,并对按4∶1的比例制作的吊钩模型进行等量逐级加载试验,同时利用电阻应变法对吊钩模型上危险点的应变进行同步测量,计算得到吊钩模型出现局部屈服时的载荷,从而根据相似关系确定了该起重吊钩的实际极限承载力和安全系数.试验结果表明,该起重吊钩在额定工况下是安全的,其安全系数约为1.14；提出的方法可以有效测定大型吊钩的实际极限承载力,以确保大型起重吊钩的安全可靠.