ST A TIC AND DYNAMIC ANAL YSIS OF SPACE FRAME Anand Krishnan.M , Jithin Pallath P School of Mechanical and building sciences, VIT University, Vellore - 632014, Tamil Nadu, India ABSTRACT : This study is based on space frame used for formula SAE. In this study we focus to build a frame, which is stiff and safe for the driver. Design model was prepared using anthropometric parameters of tallest driver (95th percentile male), SAE rules book and design knowledge. Static and dynamic analysis is done to validate model. One of the dynamic characteristics we focus in our study is the natural frequency .Different frequency modes were analysed and found considerable factor of safety as required. Keywords -Space frame, Modal Analysis I.INTRODUCTION Space frame are widely used by sports cars and in competitions like formula SAE and in mini Baja design competition Since the car have to perform in very high acceleration, braking, handling and safety aspects, each part of the frame should have d esign for good stiffness, strength and durability. A space-frame is constructed from an arrangement of small, simple members which make up a larger frame. A space-frame is analogous to a truss style bridge which is made up of small members in a triangular pattern which are always in pure compression or tension. Light weight is a primary goal for all components in a race car as a lower weight requires less force to accelerate by the same amount. So given the same force, a lighter car will accelerate quicker. Stiffness is also a desirable property for a race car chassis to have. These properties can be well in cooperated in space frame. The global vibrational characteristic of a vehicle is related to both its stiffness and mass distribution. The frequencies of the global bending and torsional vibration modes are commonly used as benchmarks for vehicle structural performance. Bending and torsion stiffness influence the vibrational behaviour of the structure, particularly its first natural frequency. The mode shapes of the car chassis at certain natural frequencies are very important to determine the mounting point of the components like engine, suspension, transmission and more. Therefore it is important to include the d ynamic effect in designing the chassis. This paper deals with the design, static and modal analysis, carried out using ANSYS Workbench. II.CHASSISLOADINGFrame is considered as a fabricated structural assembly that supports all functional systems on vehicle. The assembly may be of a single welded structure, mu ltiple welded structures or a combination of various composites and welded structures. Depending upon applica tion of load an d their direction of application, chassis is deformed in respective manner pointed as follows: Longitudinal Torsion Vertical Bending Lateral Bending Horizontal Lozenging III.METHODOLOGYThe model is made in ANSYS using the key point and given pipe cross-section having outer diameter 25 mm and thickness 3mm. The material for pipe we selected was stainless steel with yield strength 200MPa.Meshing and analysis done on ANSYS. The vehicle load considered is 300 Kg. Detail brake up is show below in Table 1 (Mass r ound up to 300 kg to includes mass of wishbones (front and rear), petrol tank , radiator etc ).
