Investigation of material effects on the passenger car’s frame structures in case of collision by Ansys LS-DYNA

This paper evaluated the effect of auto framing materials to passenger in collisions by Ansys LS-DYNA simulation software and analysis data by Hyperview software. Process simulation helps authors problem research, survey the feasibility of replacing traditional steel materials in the automotive manufacturing industry in Vietnam by carbon fiber composite materials. In addition, the simulation also allows the author to easily change the contact angle, the velocity of impact on a flexible, easy to achieve high economic efficiency during the actual test.


INTRODUCTION
Reduced self-weight of cars and increased passive safety are two important factors when designing automobile frames, shell. During the design process, typically some parts anticollision on cars will be made from synthetic resin to absorb energy. Also partial skeleton structure is also designed to be able to absorb the highest energy is intended to increase the reliability and safety of people and vehicles.
The examination of the anti-collision or safety for people and vehicles are evaluated by analyzing the collision process. Impact assessment process is usually done under the following methods: -Experiment; -Simulation the impact of the software.
The first selection method with the accuracy and reliability but high cost and implementation process is extremely complex, so not suitable for the current conditions in Vietnam. The application of simulation software collision between two cars to solve the problems of reliability frame, shell and passive safety has brought high accuracy while reducing costs and time of implementation experience. To gradually develop mandatory standards applied to the passenger car's frame structures design, manufacturing and assembly in Vietnam, including taking into account the requirements for structural strength, the material of the frame, shell self protection when the collision occurs. Therefore in this paper, the authors use the LS-

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DYNA ANSYS software and analysis data software on Hyperview to determine the influence of framing materials, to passenger cars bone collisions to determine Bumpers possibility of framing materials, peel through the safety standards of the European people.

FINITE ELEMENT MODELING AND SAFETY STANDARDS FOR COLLISION
Problem analysis techniques collision dynamics instant by simulation in ANSYS is used to determine the response of structures under the influence of time-dependent loads. We can use this type of analysis to determine the displacements, deformation, stress and timevarying forces. Simulations provide a detailed physical phenomena occurring in the structure of the model since it enables the engineers can adjust the texture before finalizing the design to put into production.
Collision simulation process is performed using software finite element simulation. A finite element model was designed and entered into LS-DYNA ANSYS with the boundary conditions, loads and element type defined conditions close to the actual collision.

Finite element models
The SAMCO-BT3 and passenger car's frame structures model designed in SolidWorks ( Figure 1) * IGES file is exported, then imported into the software Hypermesh to build finite element. By using the meshing method automesh on each array of car's frame structures (type SHELL element 163), we obtain a finite element model ( Figure 2) The HIC limit is 1000, while the HIC from 1500 to 2000, brain severe injury resulting in death Standard chest injury SI, SI limit is 1000: This limitation is based on biomechanical studies that chest can withstand 60g acceleration of 3ms without injury, the degree of compression is limited 3inches chest.

SIMULATION
The author simulated side collision between the same two cars with the velocity and impact angle different. The SAMCO-BT3 and passenger car's frame structures is CT3 steel material, then replaced respectively by composite materials with similar conditions (table 1) [5]. The load placed on the vehicle model is kinetic energy collision of car collisions 2 2 1 mV T  [4], have varying value depending on the method, direction and magnitude of the initial velocity vehicle collisions. The magnitude of the collision velocity decreases from V = V0 (initial velocity) until V = 0 (velocity end collisions) during analysis is 0,1 seconds collision. During this time we divided into 100 steps, so the increment of time is 0,001 seconds. In each step of the program will record the results.

RESULTS AND EVALUATION
Simulations in the case in (Table 1)     The results were as standard and standard HIC SI According to the timeline the collision to passengers using carbon fiber composite materials have greatly reduced compared to vehicles using steel materials.
The impact force is reduced due to the energy absorption of carbon fiber composite materials.

CONCLUSION
From the chart we see time acceleration affected passengers collided when replaced with composite materials greatly reduced.
The HIC value standard, SI showed the car using carbon fiber composite materials are always lower than carbon steel materials.
Energy absorption capacity of carbon fiber composite materials is very high so it reduces injury collisions.
From the above results show that use of carbon fiber composite materials in industrial production for passenger cars chassis because it features very good impact reduction.