Dynamic analysis of the double crank mechanism with a 3D translational clearance joint employing a variable stiffness contact force model

Oblique collisions are more likely to happen in the realistic translational joint with clearance, compared to the full front impacts. It can be a quite demanding task to evaluate how oblique contact influences the system responses. In this connection, a modified model to assess the contact forces generated in the 3D translational clearance joint is presented, together with its application in a double crank mechanism. The influence of the oblique impact, as well as the geometrical changes of the contact region, is introduced to this model. The effects of impact velocity and initial inclination angles were numerically analyzed in a two-body oblique contact system as a demonstrated example. Referring to the simulation results obtained from software ANSYS/LS-DYNA, the accuracy of the proposed model was proved. Numerical investigations were carried out for a double crank mechanism with rigid bodies to study the effects of crank speed and clearance size on the dynamic behaviors. Poincare portraits and acceleration of the output element were utilized to assess the system behaviors. The results demonstrate that the translational clearance and oblique contact can have a remarkable influence on the system responses. Furthermore, an experimental rig was established based on a mechanical press to achieve some experimental validations.