Transportation machine manufacturers are putting in efforts on research based on weight reduction. One of the representative materials for weight reduction is Fiber Reinforced Plastic (FRP). Increased used of FRP, glass fiber and carbon fiber could be a way of weight reduction. It is almost unavoidable to generate holes or notches during structural design. Little research have been carried out based on cracks with respect to materials used for design. The utilization of finite element analysis and the reliability of the analysis methods are increasing in order to promptly cope with the damages in materials. In this study, Compact Tension (CT) model based on ASTM E647 was designed using SM45C, steel for structural use, short fiber Glass Fiber Reinforced Plastic (GFRP), and woven type Carbon Fiber Reinforced Plastic (CFRP). In addition, J-Integral, which is a factor for determination of growth of crack that appears in cracks, was applied to general structure analysis. J-Integral is an equation of the body force of the material and strain energy in accordance with the loading force, and illustrates the crack growth using energy release rate. J-Integral values of SM45C, short fiber GFRP and woven type CFRP were found to be approximately 74,978 mJ/mm², 7492.3 mJ/mm² and 6222.4 mJ/mm², respectively.

This study focuses on these issues and includes the static fracture experiments with two forms of specimens; aluminum foam DCB and TDCB bonded with the type of mode III, a simulation static analysis to verify this experiment, and analysis of fracture behavior of adhesive interface of structures attached with aluminum foam by shape and thickness. The thickness of DCB and TDCB specimens designed in this study are set as variable t, and each thickness is t = 35 mm, 45 mm, 55 mm. According to forced displacements, the maximum reaction forces of DCB specimens due to thickness were approximately 0.35 kN, 0.45 kN, 0.54 kN, and the maximum reaction force of TDCB were approximately 0.4 kN, 0.52 kN, and 0.63 kN respectively. We expect the data according to variables to be easily investigated without a separate testing process, and effective analysis of the mechanical characteristics of aluminum foam DCB and TDCB.

FE analyses have been performed to characterize triaxiality of Eco-Al7021-T6, one of representative environmentally-friendly materials with lightweight effect, in this study. Also, a novel shape specimen with double notched and a central hole, i.e., DNC specimen, was suggested to obtain two different values of triaxiality from one trial simultaneously. Tensile tests for the standard type specimen were conducted and true stress-true strain relationship, as well as force-displacement curve were obtained. It was revealed that two different values of triaxiality were successfully achieved from the novel DNC specimen, and the number of tests for triaxiality can be reduced with the use of the DNC specimen.

This study uses finite element analysis to evaluate the forming load of tool entrance angle of the cold forward extrusion molding process of helical gear; this can replace the spur gear applied to the Electronic Parking Brake (EPB) system. A cold forging process is often used in the automobile industry as well as in various industrial machines due to its high efficiency. Finite element analysis is frequently used when interpreting results of the forging process. Formality was evaluated by calculating tooth profile filling rate of helical gear. Change in required forming load was investigated when the entrance angle of forward extrusion tool die was changed from 30° to 60°, also by finite element analysis. We suggest suitable tool entrance angles.