The Method Of Mechanical Structure Dynamic Load Identification Based On The Strain Information

Finite element analysis technology is widely applied to product design, the researchers need to provide accurate load information for the model. Many kinds of loads, such as the impact load wheel stands during vehicle is moving, the complex load large building or bridge suffers, etc. is difficult to obtain. Therefore, load identification technology has a wide engineering background and significant engineering demand value. This paper uses D-optimal design theory to determine the number and location of the measuring point that used to measure dynamic response. The Craig-Bampton method is used to overcome the pathological problem that the DOF of the system is very big, but the number of point used to measure response is small, which can reduce the error of the load identification. The main research contents are as follows:(1) Elaborate the basic theory of dynamic load identification, including the modal coordinate transformation of the multiple degree of freedom system and the decoupling of the differential equation, which can provide basic theory for load identification by measuring strain.(2) To solve the problem how to arrange measuring point during dynamic load identification, the distortion caused by modal truncation, D-optimal algorithm and Craig- Bampton model reduction method are proposed. Research on the method of how to choose the best measure point and modal reduction are studied in detail.(3) Set the cantilever beam, a type of motorcycle as the research object, use the method proposed in this paper to obtain exciting force, and demonstrated the method is effectiveness.