Dynamic substructure method is an effective method to analyze complex mechanical systems and structural systems. Although some scholars have used the dynamic substructure method to establish the dynamic model of the gear system with flexible box, these researches generally rely on manpower to couple the substructures, that is, to manually integrate the substructure models into the system model according to the connection relationship of the components, which is lack of standardization. The shearer cutting part studied in this paper consists of a motor, nine fixed shaft gears, eight gear shafts, two-stage planetary gear train, a drum and a box. The dynamic models of each part are different in nature (linear and nonlinear, lumped parameter and finite element). There are many kinds of connections among them. If these substructure models are manually integrated, the system model will be non-linear It’s often difficult. In addition to the heavy workload and time-consuming, but also extremely easy to make mistakes. The above phenomenon hinders the promotion of dynamic substructure method in the dynamics of complex gear system, which is not conducive to the extensive and in-depth research on practical engineering problems.
The key steps of applying dynamic substructure method to gear system are summarized, and the normalized matrix expression of substructure set is derived, and the algorithm is realized by MATLAB programming. This set of working methods and related programs are collectively referred to as the normalized modeling framework of complex gear system.
The dynamic substructure method is essentially a modeling idea of “breaking the whole into parts and integrating the zeros”. “Breaking the whole system into parts” refers to the process of artificially decomposing the whole system into several substructures and establishing its dynamic model; “integrating the substructures into whole” refers to the process of integrating the substructure models into the coupled system model according to the coordination relationship between the interfaces of each substructure. The following describes the standardized modeling process of substructure decomposition and substructure assembly.