Numerical simulation study on the working process of pin puller

The pin puller is a pyrotechnic separation device, widely used in the aerospace field due to its fast response and high reliability. However, pin puller devices have a one-time function and complex, variable charge states, resulting in high testing costs and the absence of accurate performance prediction models. Here, a finite element model of the pin puller is established, using the pressure curve measured by the chamber pressure testing device as the input excitation to visualize the motion. Based on the model, an in-depth analysis of the internal structural motion processes, such as shear pin fracture and buffer sleeve locking deformation, is conducted. In particular, using the chamber pressure curve as the model input excitation eliminates the need for extensive testing to measure charge parameters, which can solve the problem of lacking accurate charge performance parameters under complex charge conditions. The model is validated using a piston velocity testing device, and the experimental results show good consistency with the model calculation results, with a relative error of less than 5%. The results indicate that the established model can accurately predict the motion of the pin puller, providing a theoretical basis for its mechanical performance analysis.