In this study, the structural analysis was carried out according to the structure of lumber support. For the optimal design of the automotive lumber support, It was examined which one was most stable among three models A, B, and C. As the result of structural analysis, all three models showed the greatest deformations at the wire portion of the lumber support, and model A showed less equivalent stress and deformation compared with models B and C. As model A showed the lowest equivalent stress and deformation among all models, model A was shown to be the model with the excellent strength. This analysis established the stable design by comparing models A, B and C. Also, It is thought that this study result can be highly utilized at the seat design of real automobile.

In this study, the experiments and analyses were carried out in order to investigate the fracture characteristics on the adhesive at the specimen bonded with aluminum and aluminum-foam. The same conditions were given for the experiments and analyses. The results are investigated by the graph of reaction force according to displacement. It was found that the experimental and the analytical data were very similar to each other. On the basis of the data, the reliability of the analysis data could be confirmed. The notches were produced at the distances of 40, 110, 150, and 190 mm from the front of the test specimen, and the maximum reaction force was compared accordingly. It was found that the highest reaction force was generated at the front end of the adhesive and the lowest reaction force was found at the middle of the adhesive interface. Finally, when the equivalent stress in the test specimen was examined, it was found that the highest stress was obtained at the distance of 110 mm. It can be deduced. As the notch formation point are similar to the point when stress is dispersed as the adhesive is peeled off, it is possible to infer the high stress compared to other test specimens.

In this study, we investigated the properties of adhesive materials with different lightweight materials such as CFRP and Al-foam. The specimens were tested and analyzed using DCB (Double Cantilever Beam) specimens. In order to secure the reliability of the finite element method, the test and analysis were carried out, and the reliability of the finite element method was secured by using the graph of reaction force to displacement based on the experiment and analysis. The study on the adhesive failure characteristics according to the position of notch hole proceeded. Notch holes were generated at the locations of 40, 110, 150 and 190 mm from the beginning of the specimen near the bonding interface, and the analysis conditions used were the same as those used for securing reliability. The obtained study results are compared with reaction force and equivalent stress. In the case of reaction force, the overall tendency is similar but the difference in maximum reaction force is found. It was found that higher reaction forces appeared at the beginning than at the end of the bonding interface. When the equivalent stresses in the specimens were examined, the value of CFRP was seen to be 30 times higher as much as that of Al-foam.

Light weighting is one of techniques considered importantly at designing the mechanical structure using the light weight material. This study deals with aluminum-6061 and aluminum foam which stood in the spotlight of light weight material. And the finite element method for safety evaluation has been carried out in order to prevent from the damage and fatigue fracture due to crack appearing at the mechanical structure with this material. The simulation analysis as MT(middle tension) test was carried out by using the core of aluminum foam and the material laminated with sandwich structure of Al-6061. The mechanical structure is linked together with various parts and designed as the material with hole or crack. So, MT test is one of the test methods to evaluate the fatigue fracture characteristic of material and the strength inside material with the center crack by applying the load to the part connected pin. The real material strength is thought to be evaluated through the study result of MT test analysis.

At modern mechanical and automotive industry, the material with light weight proceeds in order to thr environmental issue and high performance. Machine part is fastened with numbers of bolts and nuts. Generally, the metal part at mechanical structure is fastened with bolt and nut through puncturing. But it is difficult to puncture at CFRP with the property of fiber structure like the general metal. In this study, the fracture behavior is investigated by the hole and crack at the plate of the unidirectional CFRP due to ply angle. The thickness of plate is 2 mm. Two laminates with the varied ply angles are layered and eight plies are made. The hole is placed at the center of plate and the cracks with the length of 2 mm are generated on both left and right sides from the hole. The finite element program of ANSYS is carried out in order to analyze the CFRP with fiber layer. As analysis, the maximum reaction force and equivalent stress are investigated due the angle of ply. The reaction force in case of the stacking angle of 90° is shown to be greatest among all specimens.

The composite material has the strong durability and light weight as inhomogeneous material. Nowadays, CFRP composite has been noticed as the light weight, high strength and long fatigue life. This study has been carried actively. In this study, the properties of tensile strengths of CFRP, stainless steel are analyzed, and compared each other. In order to secure the data, the tensile specimens with notches of same size by using CFRP, and stainless steel are manufactured and experimented. When the forced displacement of about 11.5 mm proceeds in case of stainless steel specimen, the maximum load of 31000 N is shown simultaneously with the fracture of specimen. When the forced displacement of about 6 mm proceeds in case of CFRP specimen, the maximum load of 16000 N is shown. So, the structural safety becomes highest at CFRP specimen among these specimens. In this study, the finite element analysis is carried out in order to compare with the experimental results. It is verified that the experimental and analysis results are similarly shown each other. Through the result of this study, it is thought that the simulation analysis data with no experiments are trustworthy at using as the real tensile experimental data.

Composite materials have the strong durability and light weight as inhomogeneous material. These material are manufactured by combining and maximizing the advantage of each material. Among these various materials, stainless steel, aluminum and brass has been used generally. Prior to using, the preparatory experiments are demanded in order to obtain the material strengths. In this study, the tensile tests are carried out with the specimens of stainless steel, aluminum and brass. These tensile specimens of same standards are made with the notches at both sides of specimen. When the forced displacement of about 11 mm proceeds in case of stainless steel specimen, the maximum load of 31000 N is shown simultaneously with the fracture of specimen. When the forced displacement of about 6 mm proceeds in case of aluminum specimen, the maximum load of 20600 N is shown simultaneously with the fracture of specimen. When the forced displacement of about 7 mm proceeds in case of brass specimen, the maximum load of 25000 N is shown. In this study, the finite element analysis as ANSYS program is carried out in order to verify these experimental results. The experimental and analysis results are similarly shown each other. Through the result of this study, the analysis data with no experiments are thought to be trustworthy as the tensile experimental data.