| Biography | |
|---|---|
 Prof. Wenbin Hou Dalian University of Technology, China |
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| Title: Mechanical Behavior of Composite T-Joint for Lightweight Automobile Structures | |
| Abstract: Nowadays there are growing concerns on energy conservation and environmental protection, and the development of lightweight automobile structures has been taking an accelerated pace. Carbon Fiber Reinforced Thermoplastic Composites (CFRTP) has been the most promising lightweight material in automobile. T-joint, which taken from the connection between the B-pillar and longitudinal rocker of a vehicle body structure, plays an important role in improving both vehicle stiffness and strength in a side impact. Therefore, it is of great significance to study the mechanical behavior of CFRTP T-joint structure for the application of composite materials in automobile body. In our study, single hat shaped CFRTP T-joint which is simplified from B-Pillar was fabricated using high temperature and pressure molding process. Two kinds of bonding modes were adopted to connect the outer and inner structure, namely adhesive and adhesive & riveting. In the quasi-static tests, the T-joint was subjected to out-of-plane bending and bending-torsion coupling conditions. Analytical, numerical and experimental inveatigations were performed into each load condition. The relationship between failure mode and load-displacement curve was analyzed. The analytical, numerical and experimental results were compared. Results show that the bending stiffness damping of T-joint is due to progressive failure of CFRTP laminate. The failure results include matrix cracking, matrix/fiber deboning of transverse fibers, delimitation and fiber breakage leading to transverse rupture. The failure mode are rupture and shear failure on the top surface and laminate crushing on the bottom surface, as shown in Fig. 1. In the FEA results, the failure index is represented by different colors varying from blue-low value to red-high value; and the loci of the predicted damages match well with those observed in the test as indicated by white circles. As shown in Figure 1(a and b), the damages, which are detectable on the top surface, are similar to the experimental observations. In Figure 1(c), the damage ruptures appeared at the bottom surface are also well predicted by the FEA simulation. Hence, there exists a good agreement between the experimental observations and finite element method (FEM) predictions. The results of experimental phenomena are in agreement with numerical simulations including stiffness, peak load, failure locations and stress-strain in both out-of-plane bending and bending-torsion coupling load conditions. FEM and experimental results can prove the validity of analytical model in flexural modulus. In the dynamic tests, experimental investigations and finite element method were carried out into three different velocities and two different bonding modes for the composite T-joints. Four distinct failure modes, classified as top surface crack (I), side wall rupture and collapse (II), bottom surface rupture (III) and overlap opening (IV) were identified in the dynamic tests, as shown in Fig. 2. Effects of failure modes to crashworthiness characteristics were invested. It is found that mode IV has little influence on the energy absorption capability of CFRTP T-joint. And Mode III combined with mode I and II or mode IV significantly influences the energy absorption capability of T-joint. The energy absorption capability (SEA) increases with the increase in impact velocity; whereas the connection modes seemed insensitive to energy absorption capability. In addition, a finite element modeling methodology based on progressive damage model was developed to study the impact behavior and energy absorption characteristics of T-joint. Cross-ply stacking pattern was carried out to simulate the fabric layers. Simulation results compared very well with the experiments in terms of the load-displacement behavior, specific energy absorption, and surface strain distribution, and provided a good depiction of the failure process. | |
| Biography: Dr . Wenbin Hou is a professor and doctoral supervisor of School of Automotive Engineering in Dalian University of Technology. In 2003, he received his doctor's degree in solid mechanics from Jilin University. He was a visiting scholar at the School of Mechanical Engineering, University of Michigan, USA, and a senior research scholar at the School of Aeronautics and Mechanics, University of Sydney, Australia. He is now the deputy director of the Department of Vehicle Engineering and Mechanics, Dalian University of Technology, director of Liaoning Advanced Vehicle Design and Manufacturing Engineering Technology Center, a regular member of the State Key Laboratory of Structural Analysis of Industrial Equipment, and selected as one of the thousand talents of Liaoning Province. He is also a council member of The China Society of Automotive Engineering and a member of the Science and Technology Award Committee of the China Society of Automotive Engineering. He has served as the evaluation expert of national Science and Technology Award and China Automobile Industry science and technology Award. He has presided over more than 20 projects including national natural Science Foundation of China key and general projects. He has published more than 60 SCI papers. He has won the second prize of National Science and Technology Progress award, the first, second and third prizes of China Automobile Industry Science and Technology Progress Award and the second prize of Liaoning Province Teaching Achievement Award. | |
