International Journal of Automobile Engineering Research and Development (IJAuERD) ISSN(P): 2277-4785; ISSN(E): 2278–9413 Vol. 4, Issue 6, Dec 2014, 9-14 © TJPRC Pvt. Ltd.
DESIGN OPTIMIZATION AND STATISTICAL CRASH ANALYSIS OF CHASSIS FRAME FOR OFF ROAD VEHICLE SATINDER SINGH & BEANT SINGH Department of Mechanical Engineering, PCET Lalru, PTU Jalandhar, Punjab, India
ABSTRACT In today’s modern world, safety to driver and passengers is a major concern to every car manufacturer. For accomplishing this, new standards are being set for the safety of the occupant in different car scenarios like frontal head collision, side impact, rear impact and rollover. The automotive chassis is the main load carrier and energy absorbing component in all crash events. In the modern world, fuel consumption also constituted as a serious issue that has to be considered. Keeping all these constrains in consideration, a light and strong material should be used in chassis. In current work, chassis has been designed using computer aided design (CAD) programme Solid Works and was analyzed using a finite element analysis (FEA) programme ANSYS. The current research provides a standard finite element analysis procedure for designing off road vehicle chassis. A multi body dynamic crash analysis is an option to understand the exact behavior of the chassis for frontal and rear head collisions, to study the effect of speed of a vehicle. This report includes the creation of the safe design for dynamic impact analysis under different loading conditions (different pipe size and velocity).
KEYWORDS: FEA, ANSYS, Solid Works INTRODUCTION Off-road vehicles are considered as most powerful vehicles as they have the capability to drive through the rough, gravel surface or off paved surfaces. These are generally characterized from their independent suspension systems, open treads and wide tyre’s. Traveling on off-road terrains require vehicles capable of accommodating off-road driving such as ATVs. Large ground clearance, off road tyre’s and drive train all of these conditions are easily accommodated in these kinds of vehicles. Some companies only manufacture the vehicles for off road purpose only. Most of these off-road vehicles are tailored with specially designed low gearing system which helps the operator to make the utmost engine’s power capability while moving it slowly through challenging terrain. These vehicles are designed for both drives i.e. four wheel drive and two wheel drive so that the operator can use the vehicle as per the power required during driving. The objective of current work is to study various chassis design of off road vehicle and their analysis under static and dynamic loading conditions, and to develop a optimize design of chassis with keeping a view to minimize weight, provide safety to driver and to give maximum efficiency [1].
FEA FEA is a great computational tool in engineering field which is used to accomplish various engineering analysis. In FEA the whole surface is divided into small confined area i.e. mesh generation which divides the whole complex problem into small elements which is performed on simulating software which works on the different codes. Finite element www.tjprc.org
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Satinder Singh & Beant Singh
analysis (FEA) calculates how a product reacts to forces, vibration, heat, fluid flow, and other physical effects. FEA works by breaking down an object into a large number of finite elements after that mathematical equations helps to predict the behavior of each element [2].
ANSYS ANSYS is great simulating software which has the environment for solving the non-linear analysis and has the very easy set up for the complex problems, even multi-physical simulations are possible. ANSYS can import CAD data and also has features to build geometry with in itself. ANSYS Workbench is a platform which integrate simulation technologies and parametric CAD systems. ANSYS can carry out advanced engineering analyses quickly and practically by its variety of contact algorithms, time based loading features and nonlinear material models [3].
SOLID WORKS Solid Works is a 3D solid modelling software package developed by the French company Dassault Systems, used to develop various concepts designs based on parametric technology. It is used extensively to develop conceptual 3D solid models of off road vehicles and final optimized model and is able to convert cad data to IGS and STL file formats, so that can be assessed by analysis software package and rapid prototyping machine.
METHODOLOGY
Figure 1 The purpose of this section is to give a basic knowledge of the methodology that was used to analyze the Chassis. The flow chart shows a generic illustration of the major steps involved in the design optimization process.
MATERIAL SELECTION AND LOADING CONDITIONS The materials used in the cage must meet certain requirements of geometry, and other limitations. The main criteria we took into consideration when choosing the material for the roll cage are safety, cost and durability. Table 1: Material Properties of Frame and Wall Sr. No.
Material
1 2
AISI 1010 Concrete
Impact Factor (JCC): 5.1066
Young Modulus (GPA) 200 140
Tensile Strength (MPA) 325
Yield Strength (MPA) 180 5
Poisson Ration 0.30 0.21
Density X 1000 (Kg/M3) 7.872 2.4
Index Copernicus Value (ICV): 3.0
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Design Optimization and Statistical Crash Analysis of Chassis Frame for Off Road Vehicle
After defining the material properties, the loading conditions need to be defined. In Explicit dynamics different velocities were given to the chassis and deformations were measured with respect to given velocities while hitting the wall. The analysis time 5 e -3 sec was given to chassis. Table 2: Different Velocities Given to Chassis Frame
RESULTS AND DISCUSSIONS Computer Aided Design (CAD) model is the basis to create a complex FEA model, there began a quest to develop a CAD model. With the reference dimensions, a CAD model was developed in Solid Works 2014, a one dimensional model was created for the ease of calculations during analysis [4].
Figure 2: Wire Frame Model of Off Road Vehicle Chassis
Figure 3: Chassis Analysis Condition for Frontal Impact
Figure 4: Maximum Displacement in Frame at Velocity 15 M/S for Fontal Impact www.tjprc.org
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Satinder Singh & Beant Singh
Figure 5: Maximum Displacement in Frame at Velocity 20 M/S for Fontal impact
Figure 6: Maximum Displacement in Frame at Velocity 25 M/S for Fontal Impact
Figure 7: Chassis Analysis Condition for Back Impact
Figure 8: Maximum Displacement in Frame at Velocity 15 M/S for Back Impact
Impact Factor (JCC): 5.1066
Index Copernicus Value (ICV): 3.0
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Design Optimization and Statistical Crash Analysis of Chassis Frame for Off Road Vehicle
Figure 9: Maximum Displacement in Frame at Velocity 20 M/S for Back Impact
Figure 10: Maximum Displacement in Frame at Velocity 25 M/S for Back Impact
CONCLUSIONS The basic objective of the present research was to optimize the design of the off road vehicle frame by reducing the thickness of circular pipe. Deformations observed by reducing the thickness of the frame shows that if we use the pipe with thickness of 1mm the deformations are quite similar as compared to design of the off road vehicle which is taken into consideration in this research. According to the considered design, thickness of the frame should be 1.67 mm but if we reduced it to 1 mm, percentage deformation observed in the chassis frame is only 2 % and moreover the weight of the chassis reduces to 21 kg. Which shows that the frame is light weight and vehicle can generate more torque and power.
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Charles M. Farmer, Elisa R. Braver and Eric L. Mitter, Two vehicle side impact crashes: The relationship of vehicle and crash characteristics to injury severity, A & d. Anal. and Prev, Vol. 29, No. 3, pp. 399-406, 1997.
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Kim, S. S, Shabana, A. A, and. Haug, E. J, Vehicle Dynamic Analysis with Flexible Components, Iowa State University, 1984.
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V. Veloso , H. S. Magallanes, G. I. Bicalho , E.S. Palma, Failure investigation and stress analysis of a longitudinal stringer of an automobile chassis, Engineering Failure Analysis vol. 16, 2009, pp.1696–1702.
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Norma F. Hubele and Mark W. Arndt, A review of crash data analysis in a defect and recall investigation of the general motor c/k pickup trucks, Accid. Anal. And Pm, Vol. 28, No. 1, pp. 33-42
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