Proceedings of 2012 International Conference on Mechanical Engineering and Material Science (MEMS 2012)

Simulation and Improvement of Vehicle Frame Using

FEM

Wang Li-rui Yang Xiao-long

College of Mechanical and Vehicle Engineering, Hunan College of Mechanical and Vehicle Engineering, Hunan
University University
Changsha, China Changsha, China
wanglirui91@126.com xyangsuc@163.com

Abstract—In order to develop and improve the design of a new

type of vehicle frame, this paper illustrates the modeling and
simulation of a new type of vehicle frame. Modeling of the frame
was done via UG NX6.0, and simulation of the frame was done
through ANSYS 12.0. Based on the simulation results, component
was designed to strengthen the frame. Based on the results and
improvements, the design was accomplished.

Keywords- vehicle frame; FEM; ANSYS 12.0; strengthening

component

I.INTRODUCTION
Fig 1 Frame model
Vehicle frame is to fix engine, vehicle body, steering
components and transmission components, and is the key part In this model, the engine is put in the rear of the frame and
of the vehicle. Frame with ideal structure will improve the the vehicle was driven by the rear wheel (RR). Moreover, to
performance of the vehicle significantly. Our previous study make the frame suitable for the tire with diameter of 305 mm
calculated the wheel base and wheel span of the vehicle, to be and make the center of gravity lower, the bearing pedestal was
1300 mm and 450 mm, respectively. Therefore, the frame designed in the rear of the frame on the beam of the steering
should be designed within such limitations. To be compatible part.
with the steering and transmission part, the width and length are
350 mm and 2000 mm, respectively.
III.Definition and Application of the Load and Boundary
Additionally, to reduce the weight of the frame, 6061 Conditions
aluminum alloy, which contains Mg and Si, was used to
manufacture the frame. Moreover, carbon fiber was applied in The load mainly includes the weights of the engine and the
manufacture of the chair and other accessories to additionally driver, which are 20 kg and 45 kg, respectively. Acceleration
reduce the weight. when braking is 2 m2/s. Acceleration when steering was 6 m2/s.
The safety index was defined as 1.5 according to previous study.
Based on the work above, in order to assemble an The load was applied to the frame where the engine was to be
eco-power racing vehicle and to join Honda Eco-mileage mounted. The sum of the wheel weight and weight of other light
Competition and other relevant competitions, this paper used components were balanced against the weight to the engine (fig
finite element method to simulate and improve the performance 2).
of the frame to accomplish the design which can meet the
requirements of the vehicle.

II.Establishment of the Model

Based on our previous study [1], the requirement of the new
frame, and according to our investigation of the market, we
chose the 6061 aluminum alloy with the length, width and
thickness of 38 mm, 25 mm, and 2 mm, respectively. The frame
was then modeled via UG NX6 as fig 1.

Fig 2 Static load and boundary conditions

© 2012. The authors - Published by Atlantis Press 627

 Boundary conditions were restraints on the 4 holes where respectively. After the load was applied, including the weight
the front axle and bearing pedestal were to be mounted. and acceleration induced pressure on the frame, solutions were
obtained and plotted (fig 4).
IV.Structural Analysis

A.Definition of Element type and Material

Import the model from UG NX6 and use solid 45 element to
mesh the whole model. Solid 45 element is designed for 3D
solid structure and was defined by 8 nodes. Every node has
three degrees of freedom along x, y and z dimensions. This
element has the character of plasticity, creepage, expansion,
stress strengthening, large deformation and large displacement,
and is appropriate for the isotropic materials. For these reasons
above, solid 45 element can be used for the analysis of the
vehicle frame. 6061 aluminum alloy is an isotropic material. Its
Young Modulus is 68.9GPa, Poisson’s ratio is 0.33, yield
strength is 55.2MPa and fatigue strength is 62.1MPa.

B.Meshing of the vehicle frame

After the element type and material defined, mesh the
vehicle frame. Use smart size 5 to mesh the whole vehicle
Fig 4 braking condition solutions
frame and then refine the meshing at key positions. There are
280172 element s meshed in this process. As we can tell from the simulation, the displacement from
the X, Y, and Z dimensions of the frame are 0.059 mm, 0.40
C.Applying of Load and Solution mm, 0.044 mm, respectively. The stress of the frame along the
The calculation of the static load is as following procedure: X, Y, Z axes are 30.1 MPa, 22.1 MPa and 59.1 MPa,
first calculate the space of the truss under the engine which is respectively. The maximum stress exceeded the material
15000mm 2, then the pressure on the tress is 13333Pa, the space limitations which means improvements shall be made[2].
of the truss bearing the chair is 20000 mm 2, then the pressure
on the truss is 25000Pa. After applying the load(fig 2), solutions In the dynamic steering simulations, the acceleration was
were obtained and plotted(fig 3). calculated as 6 m2/s. Therefore, the pressure applied on the truss
bearing chair and engine are 48000 Pa and 32000 Pa,
respectively. After the load was applied, including the weight
and acceleration induced pressure on the frame, solutions were
obtained and plotted (fig 5).

Fig 3 static analysis solutions

As we can tell from the simulation, the displacement from

the X, Y, and Z dimensions of the frame are 0.03 mm, 0.28 mm,
0.04 mm, respectively. The stress of the frame along the X, Y, Z Fig 5 steering condition solutions
axes are 22.1 MPa, 16.1 MPa and 41.0 MPa, respectively. All
of the displacements and stresses are within the limitations [1]. As we can tell from the simulation, the displacement from
the X, Y, and Z dimensions of the frame are 0.803 mm, 0.338
In the dynamic braking simulations, the acceleration was mm, 0.133 mm, respectively. The stress of the frame along the
defined as 2 m2/s. Therefore, the pressure applied on the truss X, Y, Z axes are 37.1 MPa, 36.7 MPa and 60.3MPa,
bearing chair and engine are 19200 Pa and 7111.12 Pa,

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respectively. The maximum stress exceeded the material The lightweight design and improvement should not be
limitations which means improvements shall be made[2]. relied only on materials, rather, optimization of components
and structure shall be considered when designing[7].
V.Improvements
Sine the maximum stress exceeded the material limitations, VII.Conclusions
strengthening components should be designed to strengthen the Simulation using ANSYS 12.0 and Hyperworks has
weak positions(Fig 6). Analysis of it indicates this component successfully validated the model in static conditions and
will make the maximum displacement and stress within dynamic conditions with the safety index in mind. Based on the
material limitations. solutions, new component was designed to strengthen the frame.
After improvements above, all statistics, including
displacement, stress and load distribution are within the
material limitations. The model is appropriate for the vehicle to
join the competition.

REFERENCES
[1] Zhou Jianmei, Wang Guijiao, “Lightweight Design of an Energy
Conservation Vehicle Frame Based on FEA”, J. Tianjin Auto, vol. 9,
pp.72~74, 2008
[2] Wang Guijiao, Zhou Jianmei, “The Type Selecting and Lightweight
Designing of Energy-saving Vehicles’ Frame” ,J. Auto Technologies, vol.
Fig 6 strengthening component 9, pp. 41~44, 2008
[3] Dong Xueqin, Xin Yong, Yang Fan, “On Finite Element Modeling of a
Vehicle’s Frame Using Hyperworks”, J. Mechanical Science and
VI.Discussion Technology for Aerospace Engineering, vol. 7, pp.906~908, 2008
We also used Hyperworks to validate the model using [4] Gao Yunkai, “ Analysis of a Vehicle Body”, Beijing Institute of
another shell element type algorithm[3]. However, the validation Technology Press, 2006
shows a slight difference in the displacement in the three [5] Xia Xiaokun, Yan Fuwu, Du Changqing, “A Study on Reducing Oil
Consumption of Energy-efficient Motorcycle”, J. Motorcycle
dimensions. Although the variation will not influence the Technologies, vol. 10, pp.70~72, 2008
structural stability and safety, further validation shall be done to [6] Yin Huijun, Wei Zhilin, Shen Guanglie, “Finite Element Analysis on
verify the variations. Frame of Trucks”, J. Journal of Machine Design, vol. 11, pp.27~28, 2005
Moreover, since this vehicle, which is based on the frame, [7] Li Xiya, Li Chenggang, Hu Yujin,“General Conditions of the Finite
Element Analysis Technic”, J. Special Purpose Vehicle, vol. 1, pp.11~15,
will join the competition to compete for the lowest oil 2001
consumption, the frame seems to be a little bit heavy. This
means further improvement shall be made if more appropriate
materials are available [4][5] [6].

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