Blog #7 - Updated Validation Plan

When the stay at home order was set by the City of Houston, all shop work was stopped. The team made a complete list of all the bolts, nuts, and washers required for the entire system, along with an updated validation plan, instead of having the upright at an angle the team decided to test it horizontally to reduce the complexity of the test and make it easier to test at the shop. See Figure 1 for the updated validation method of the upright. The plan was to continue the work and perform validations after April 3rd. The updated validation plan uses a test upright without a bearing seat and uses a steel pipe to stand in for the hub. A steel ring (colored grey in Figure 2) similar to the bearing retaining ring will be welded to the pipe. This is used to support the upright. A top plate (colored dark blue) is placed on top of the upright and bolted through all. The bolt on the A-arm block will be used to hand the weights. Proximity probes will be placed on top of the upright to measure the downwards deflection. Similarly, this would be repeated for the upper A-arm block.

Figure 1: Top isometric view of new validation method

Figure 2: Bottom isometric view of new validation method

The team had an online meeting with the UH machinist to discuss some CAD changes to the uprights on Friday, March 27 to start machining. The changes consisted of adding a 0.25” fillet and 0.025 chamfer to the rear toe rod bolt on section, see Figure 3.  The only change for the front was a small fillet at the bottom of the bolt-on caliper tab, see Figure 4. The team determined the amount of material required to order, from the meeting. 

Figure 3: Rear Upright Changes

Figure 4: Front Upright Changes

The UH machinist was scheduled to return to the shop April 1st, and would have the uprights completed by the latest April 10th. Due to the extended stay at home order, the shop will continue to be closed during the duration of the order. The team is unable to get to the shop and perform physical work. The project has been put on pause until the shop reopens on April 30th and we can get back in the shop. 

Because the machinist shop will be closed until the stay at home order is lifted, the team is planning a new validation plan for other components of the system, possibly a procedure for finding the center of gravity more accurately, or testing the damper bridge strength.  With the A-arms nearly finished the validation of the kinematic motion will be one of the first things we will be able to accomplish once the shop is reopened.