During the start of this project, we had to make a plan of attack so we could hit every aspect of the accumulator container. Recognizing the complexity and magnitude of the task at hand, we divided and assigned responsibilities among our team members. This allocation of tasks allowed us to navigate the multifaceted terrain of the accumulator container with unwavering focus and precision.

Drawing upon our collective expertise and diverse skill sets, each team member assumed a leadership role in a specific category, while being wholeheartedly supported by the entire group. This collaborative approach fostered an environment of synergy and propelled our progress forward with synchronized determination. The sections below outline the topics tackled throughout the quarter.

Final Physical Prototype

CAD Model Of Final Design Using Aluminum Sheet Panels

In order to properly visualize the structure the team had to construct throughout the quarter, a proper CAD model had to be made. This went through dozens of iterations, ending in the product below. This provided the specific dimensions and a model to use for thermal analysis. Panels were then cut using a FabLight in the Design and Innovation Building at UC San Diego and assembled to resemble the structure below.

These components were used in an Instron Universal Testing Machine to produce the following Force vs. Displacement Curves: 

From here, we transitioned to the required 3-point bend test. The ruleset required a 138 mm x 500 mm sample to be held with a span distance of 400 mm and an applicator with a radius of 50 mm. The following was constructed for this test:

However, during testing, several complications and unexpected results occurred. Rather than reaching the point of failure, the fiberglass material flexed during the entire process. The sample fell into the test rig and proved unable to pass this test, and we were unable to collect the data required to compare to the alternate suggestions from FSAE.

Therefore, though unfortunate, an immediate change of materials was required to ensure a successful prototype was constructed that followed the FSAE guidelines. The team transitioned over to an aluminum sheet metal design, employing 0.09" panels for the walls and internals and 0.125" for the base and cover. Because this is a material suggested by FSAE, testing is not required.

Design and Structural Analysis of Mounting

The mounting mechanism is required by the FSAE rules to withstand a test load equal to 1/4 of the mass of the entire accumulator accelerating at 40g. In our case, the test load was 3.06 kN for the projected weight of the composite accumulator. The design consists of two major parts; the steel tabs welded to the chassis and the aluminum accumulator attachment bracket which is fixed to the skin of the accumulator container. The two are fastened with 3/8"-16 bolts and nylock nuts. The design underwent a couple of iterations, mostly in order to better ensure the structure could survive the test load in bending. The first design consisted of a single tab with the accumulator bracket fastened to the accumulator skin with bolts.  The second had two tabs in order to reduce bolt shear stress by putting it into double shear as well as increase bending resistance, and switched from bolts to adhesive to for attaching the accumulator brackets in order to avoid putting holes through the accumulator skin, which ran the risk of creating a point of possible delamination. The final added gussets to further support vertical bending loads. Below are some pictures of the CAD and analysis on the final mounting design.