More Contact With The Restraint System Virtual Prototype Simulation Efficiency

Dynamic simulation based on virtual prototype technology has become an important method for functional design of production development and innovation. However, if there are too many contact constraints in multi-body dynamic system, the simulation may be unavailable due to its inefficient and instable computational model, which limits the development of virtual prototype technology. For reducing simulation time and improving efficiency, the contact constraint activation and deactivation method is used. The main processes are as following:1. According to the numerical solution theory about the multi-body dynamic model, the intrinsic properties of the Jacobian matrix for the solving model are analyzed. The essential factor is that the Jacobian matrix of the solving model, which includes the contact constrain definitions, maintains its dimension even if some of the contact constrains do not work at current iteration step. Generally, the higher dimension of the Jacobian matrix is, the larger condition number is, which makes the solving more inefficient.2. Based on the essential factor of inefficient solution, the contact constraint activation and deactivation method is proposed to reduce the dimension of Jacobian matrix and improve the solution efficiency. Meanwhile, a simple and representational model is designed and simulated with ADAMS. The simulation result reveals that the proposed method can reduce simulation time and improve computational efficiency greatly without losing solving precision.3. A roller chain driveline system is modeled for validating practice value of the proposed method. According to the conventional dynamic simulation in ADAMS, the impact force, oscillation and the transmission efficiency are analyzed. Then compared with the conventional simulation method, the proposed method is used in the chain driveline system simulation. The simulation experiment shows that the proposed method is suitable to simulate complex multi-contact constraints systems, such as chain driveline systems. The contact constraint activation and deactivation method can not only ensure simulation precision, but rather reduce the Jacobian evaluation count, save much computational time and improve computational efficiency greatly. The proposed method has promoted the development of the multi-contact mechanical system simulation technology.