Reducing contact resistance of high current connectors on electric vehicle by controlling contact pressure and addition of plating material
This paper studies on contact resistance on copper busbar connection relative to plating materials, plating thickness, and contact pressure. This study is important because busbar connection plays an important role on electric distribution performance. A good busbar connection would have low contact resistance, therefore low energy losses and better reliability. In this study, the sample are busbar connection without plating, busbar connection with zinc plating, busbar connection with nickel plating, and busbar connection with silver plating. First aspect that is going to be tested is contact resistance measurement without load on each. The next test is contact resistance measurement with DC load of 9, 18, and 27 A. Each test is conducted with the contact pressure variation of 5.6, 7.0, dan 8.4 MPa, and with plating thickness of 5, 15, and 25 μm. The result shows that busbar connection with 5 μm silver plating have much lower contact resistance compared to all the other configuration.
Injection lap riveting
Abstract This paper presents an injection lap riveting process to connect two sheets placed one on top of the other. The process is carried out at ambient temperature and differs from self-pierce riveting because its joining principle is based on plasticity and friction without fracture and formation of new surfaces. The working principle is based on two consecutive operations - first, a dovetail ring hole is machined in the lower sheet and then a semi tubular rivet is injected through the upper sheet into the dovetail ring hole of the lower sheet, by compression with a punch. The presentation is based on a combined experimental and numerical investigation and special emphasis is put on the influence of the dovetail ring hole geometry in material flow, riveting force, and pull-out and shear destructive forces. The last past of the paper includes details of a prototype cutting tool that was developed by the authors for producing the dovetail ring holes in-site and fostering the portability and applicability of the process.
Prediction of a representative point for rail temperature measurement by considering longitudinal deformation
Monitoring rail temperature is very important for determining the safe running speed of trains and to prevent buckling. In general, the maximum variation of the internal rail temperature can be >7 ℃ depending on the point of measurement. However, there is as yet no sufficient information about how to predict the measurement point to represent the thermal deformation due to temperature distribution. In this study, the authors report a new point, called the representative measurement point, at which the rail temperature can be measured. This point considers the average deformation of the rail through structural analysis by adopting experimental and actual rail temperature data. The authors designed and installed a measurement system similar to an actual rail environment. Using the system, various data were acquired (internal/surface rail temperature and weather data) for 10 months. On the basis of these data, an analysis was done to calculate the average deformation point through thermal analysis. Finally, the representative measurement point was proposed as the position at which the average deformation point converges regardless of weather or seasons. The authors believe that the method described herein is advantageous in that it could be used in a high-accuracy temperature-monitoring system and for predicting thermal deformation and buckling.