Development of the CFRP technology for the construction of a racing car monocoque

Abstract

This project contains the developing and testing of a low production cost, carbon fiber sandwich panel technology to be used in the AIT Student Formula team. This team objective is to make a car to win in the Japan Student Formula competition. This competition is the Japanese version of the multiple Student Formula competitions around the world. The previous cars were made of steel pipe space frames. Now, the team is ready for the next level, design and built a light-weight carbon fiber monocoque. It will be covered in the tesis the initial phase of developing the new technology for the team. This includes research, design and building of equipment and testing. It will be explained the initial research of carbon types, wet carbon and prepreg, and which are the differences between it. To increase the stiffness of the body, without increasing too much the weight, it is used the honeycomb sandwich panel structure. This is composed by two layers of carbon fiber, with a honeycomb core between it. This structures will be compared and choosed the best one. There is detailed how it was designed and built an oven, used for curing the carbon. It is described the initial designs, made by Solidworks. Gradually it has been made several changes and improvements to the final design. After that, it was the building phase, using the cheap materials like wood and domestic heaters to keep it to low cost, but obtaining very good results. Finally, there is the testing of the oven in order to improve its efficiency, and the attachment of a microcontroller to keep the temperature constant. The oven its big enough to put inside the entire car frame, can rise the temperature to 135 ℃ in 30 min, and keep it constant during two hours, necessary for curing the prepreg.carbon. In it will be made the test pieces of honeycomb sandwich panel to compare which is the best material. The tests are done following the standards of ASTM for composite materials. The three tests were the ASTM C 297, C 365 and C 393, which are the flatwise tension, compresion and bending tests respectively. In addition, the bending test will be analysed with the finite element method software, ANSYS Workbench 14 + Composite preppost. Finally, the testing data is put together and the best material is chosen. After that, different options of assembling together the panels are considered, and one solution is choosen. Finally, the assembly is used in the redesign of the monocoque and a final CAD is prepared. The project schedule, sustainability and cost report are enclosed at the end of this document.