Electric kickboards provide personal mobility with a simple structure and easy operation. With these advantages, the number of users is increasing annually. However, as the number of users of electric kickboards increases, related accidents are also increasing. To prevent accidents, this study proposes the topological optimization of an electric kickboard connecting part to improve structural strength during a front collision. The results confirmed that as the volume fraction increased, the structure connecting the board and the bottom of the handle support changed to a toroidal shape, thereby lowering the maximum stress and improving the uniformity of the stress distribution. In addition, the topological optimization was safer than the connecting parts of two typical electric kickboards sold in the Korean market. These findings can contribute to improving the safety and optimizing the design direction of electric kickboards.

GMA welding process is a production process to improve productivity for the provision of higher quality of material. These includs numerous process variables that could affect welding quality, productivity and cost savings. Recently, the welding part of construction equipment had frequent failure of major components in the welding part of each subsidiary material due to shock which is very poor according to the welding part. Therefore, the implementation of sound welding procedure is the most decisive factor for the reliability of construction machinery. The data generated through experimens conducted in this study has validated its effectiveness for the optimization of bead geometry and process variables is presented. The criteria to control the process parameters, to achieve a healthy bead geometry. This study has developed mathematical models and algorithms to predict or control the bead geometry in GMA fillet welding process.