The Analysis and Creation of Composite Body Panels for the SAE Baja Car

The project “Analyzation and Creation of Composite Body Panels for the SAE Baja car” was undertaken because previous body panels made for the car were weak, and hard to remove/put back on the frame. The solution to this problem was to create composite body panels that could withstand the impact of another car, as well as contain attachment points that would allow for easy installment while not jeopardizing the materials strength. Unidirectional carbon fiber prepreg was chosen for the material because of its superior strength to weight ratio compared to fiberglass or other composites. Bighead’s closed threaded B38 bonding fasteners was chosen to be implemented in the design as attachment points. A Solidworks simulation was run with a 487.5lb force applied over the area of a 1in diameter circle in the center of each of the seven panels. The stresses were observed to be the greatest at the four points at which the fasteners were located, and the maximum stress at these four points for all principal stresses was recorded for each panel.  The maximum principal stresses for each panel were then input as load values into an excel code, which were translated to individual layers of the laminate. This code showed that the minimum number of layers needed that would stop the impact of a car, without the entire laminate breaking, was six layers. The laminate layers were oriented [90, 0, 90]s with the 90 degree oriented layers breaking first. This orientation of the layers allowed for greater deflection and a less stiff panel, which was more desirable when dealing with the impact of another car. After the calculations were completed, the carbon fiber prepreg was cut out. The bonding fasteners were placed in the middle of the six-layer laminate, with 3 layers on either side of it. The laminate was then vacuum bagged and cured in an autoclave. The final part was trimmed and cleaned up to be mounted to the car.