DESIGN AND ANALYSIS OF CHASSIS FRAME FOR ELECTRIC VEHICLE USING FINITE ELEMENT ANALYSIS

Abstract

The increasing demand for the use of electric vehicles has created the need for the design of an electric vehicle chassis frame that could sufficiently bear the load of all the components to be fitted into the electric vehicle. This paper presents the chassis frame specially designed for electric vehicles. The Ashby chart is used to select the material, and structural steel is selected after considering different selection criteria. The concepts of solid mechanics are used to select the beam of suitable cross-sectional area. Rectangular hollow section beam is selected over the beam of other cross-sections as it has better performance on vertical bending, lateral bending, and torsional deformations. Maximum bending moment calculation is performed to figure out the minimum sectional modulus for the rectangular hollow section beam. A rectangular hollow section beam with a sectional modulus value of 87.54 mm3 with dimension 120*80/8 is used for the long side members of the frame, whereas a beam with a sectional modulus of 17.05 mm3 of dimension 80*40/4 is used for the cross members linking these side members. An iterative method is used to figure out the minimum value of sectional modulus that would effectively handle all the load applied to the chassis frame. The final chassis frame has a factor of safety of 2.6 for failure by yielding criteria with maximum equivalent stress of 93.58 N ∗ /m2 . Modal analysis is performed on the frame to determine the natural frequencies of the frame. It is observed from modal analysis that the natural frequencies don’t match with the external excitation frequencies, which makes the frame safe to use. Finally, the value of bending stiffness and torsional stiffness is determined. The bending stiffness is calculated by applying the 1000N load at the centre of the frame in the negative Y-direction and using the deformation obtained, which gives the value of 6.5197 ∗106 Nm2 . Similarly, rear and front torsional stiffness are obtained by keeping the front and rear parts fixed and applying loads on free ends. The front and rear torsional stiffness values for the chassis frame are obtained to be 6.50407∗105 Nm/rad and 7.47384∗105 Nm/rad respectively. Hence, The chassis is successfully designed for static loading conditions and checked for vibrations. Further dynamic loading tests could be performed to figure out the behaviour of the chassis frame.