Plastic deformation of balls in safety coupling by collision with V-Hole was investigated in the current study. Generally, when the applied torque is greater than the maximum allowable torque, balls in V-Hole get out from the holes and the coupling loses the torque transfer capability. After balls are out from the V-Holes, the balls and V-Hole rotate at a different velocity. When balls meet the next V-Hole, they collide into the wall of the V-Hole. Due to this collision, plastic deformation and wear take place. The plastic deformation and wear may reduce the torque transfer capability of the safety coupling. The reduction in torque transfer capability was observed in the experiment. In this study, plastic deformation of balls and flange was investigated through dynamic analysis of the safety coupling. Also, the effect of relative rotational velocity on the plastic deformation was investigated.

Recently, traffic accidents and damage on the highway have increased because of overloaded vehicles. The existing overload-detecting system has a low accuracy rate. An overload-detecting system using a weigh-in-motion (WIM) system has been developed to solve this problem. The WIM system can be used to detect overloaded vehicles by measuring the weight of the vehicles. The WIM system is divided into high-speed and low-speed types. The inaccuracy rate in the lowspeed WIM system results mainly from the low response rate of the sensor when the velocity is moving at more than 20 ㎞/h. In this study, a low-speed overload-detecting pad with a hydraulic structure using a WIM system was developed to make the system more accurate. The structural and formal analysis was carried out by using a finite element method (FEM) in order to analyze the structural stability and the extrusion velocity of the system. In addition, a static load test was performed to confirm the linearity and accuracy of the pad.