The Fatigue Theoretical Load Spectrum Compiling Of Grid Structure With Welding Ball Joints Under5T’s Suspension Crane

In recent years, as an important research topic in the field of fatigue problem, the preparation process of fatigue load spectrum will directly affect its authenticity. The common method to fatigue load spectrum compiling has two kinds of test and theory, but for these two methods have not yet have a clear establishment process framework, especially for the latter, which largely limits its application and development on the practical engineering. In order to solve this problem, this paper made the main work is as follows:1. Through consulting a large number of relevant literature, made a detailed narration about the development of fatigue load spectrum dynamic. And citing over the domestic part of the set of hanging crane project instance.2. Making for a detailed introduction about the Theory compiling method of fatigue load spectrum, and on this basis, Put forward a general framework for how to compiling of space truss structure’s hanging point’s theoretical load spectrum for the first time.3. Based on the roof of the structure of laboratory size of Taiyuan University of technology, With space grid structure design software MSTCAD tentatively designed a conform to the requirements of the use of the laboratory setup has a space truss structure of hanging crane. Then, Using the finite element software MIDAS to establish the model of the structure of the network frame, and make a dynamic simulation for the Space truss structure which to consider only change hoisting load cases, and find out its control point.4. Tentatively used the theoretical compiling method to Statistic and analysis for the space truss structure’s hanging point’s load course under the random hoisting load, and document its value cumulative frequency curve, in order to verify the feasibility of the theoretical compiling method. And for the future of the space truss structure fatigue design and provides the reference for the forecast of the fatigue life.In this paper, by combining the fatigue load spectrum of commonly used preparation methods, established a theoretical framework establishment method of the overall process, and then through specific engineering to verify the effectiveness of this method, providing a certain reference value for the research for the fatigue load spectrum in the future.