In motorsport, the weight and rigidity of the chassis can influence the drivability and performance of the whole vehicle. A lightweight, high strength, high stiffness chassis is the goal and is achieved through a balance of good design and use of lightweight, high quality materials. In 2012, the UQ Racing Formula SAE team identified two key drawbacks with its UQR-12 vehicle: the weight and the weight distribution; which compromised the car’s acceleration and deceleration performance, and its handling performance.
In 2013, a Research and Development (R&D) project was undertaken for the UQ Racing team to design and build a half monocoque, half space frame prototype chassis. The purpose of this thesis is to complement the design work being carried out in another thesis, Design of a Monocoque Chassis (Bismark, 2013), by looking into the materials selection, design validation (Finite Element Analysis) and manufacture process aspects of this project.
Selecting the most appropriate material for each aspect of the monocoque involved finding a compromise between parameters such as; material properties, cost, availability and choice of manufacturing process. For the monocoque surfaces/walls, a sandwich panel structure; consisting of an aluminium honeycomb core and woven carbon fibre skins; has been chosen because it offers outstanding stiffness and strength for low weight.
The geometry of the sandwich panel has been designed based on constraints of strength and stiffness requirements set out by both the 2103 FSAE Rules and load cases that have been developed. Sandwich Beam Theory (SBT) and FEA were used to determine a suitable geometry which was validated using 3-point bend and perimeter shear strength material testing. Three sandwich geometries were tested: a 24mm core 6 ply pre-preg, 20mm core 8 ply pre-preg and a 24mm core 8ply pre-preg. Although the 24mm core 8 ply test piece only achieved 82.2% of the stiffness required by the FSAE, it was determined to be the most suitable sandwich geometry.