Papers by Author: Shun Guang Song

Abstract: To study the dynamic behavior of the extendible support structure deployment, a digital simulation using the multibody system dynamics methodology is conducted. Floating frame of reference formulations are used to establish the flexible dynamics model, in which the deformation vector of each flexible part is modeled with the component mode synthesis technique based on the Craig-Bampton method. Modal truncation is implemented through modal participation factors to reduce the computational burden. Angular displacements results of antenna panels as well as those of truss rods are then obtained and show that all parts of the structure have reached accurate positions and keep stable after deployment as expected. Start torque of the driving motor is also acquired and proved acceptable according to the design requirements. Impact forces acting on the hinges at locking moment are finally extracted to evaluate performances of locking processes.

Abstract: In order to obtain a better filling way with suitable adhesive to enhance the reliability of 3D PLUS solder joints. Finite element analysis of random vibration method was carried out. By means of the method, the effect of filling way on the stress distribution in solder joints was investigated under the condition of two types adhesives 55/9 and GD414. Stress distribution and its maximum value of 3D PLUS solder joint at peak time were acquired. Comparative analysis of the maximum stress between under filled adhesive and side filled adhesive with 55/9 or GD414 respectively. The results showed that under filled adhesive 55/9 can effectively improve the solder joint stress.

Abstract: Thermal cycling was applied to assess the effect of tin-lead solder 63Sn37Pb and lead-free solder 95.5Sn3.8Ag0.7Cu on the reliability of 3D PLUS solder joints. Nonlinear finite element method and viscoplastic Anand model were used to evaluate the stress and strain distribution and dangerous position of solders under the thermal cycling condition. The law of solder joints stress and plastic strain were finally obtained and showed significant cyclical changes. The stress and strain emerged the trend of accumulated enhancement with the process of time, then ultimately stabilized. Comparing two curves of equivalent stress and plastic strain obtained from lead-free and tin-lead solder, it was found that the reliability of 95.5Sn3.8Ag0.7Cu was better than that of 63Sn37Pb.