Didier Mejia Delgado

Mechanical Engineering Portfolio

November 2017

Didier Mejia Mechanical Engineering Portfolio

**** – 2017 Graduate Design Project: Fuel Alternative Compact Vehicle For my graduate design project, I designed a fuel alternative compact vehicle. My design met all of its requirements compact and light, yet rigid. My design, Figure 1, is powered by 2kW powered wheels with and 48V lithium batteries (not shown) which allows a top speed of 35mph (limited) and a range of 20 miles per charge. The vehicle is made of aluminum and Carbon fiber composites.

Figure 1: Final Design CAD illustration.

Requirements:

• Light – Frame weights less than 50lbs.

• Energy efficient – In terms of material use.

• Leaning Capability – The driver can lean into

a corner like a motorcycle

• 35MPH limited speed.

• High Safety Factor

• Minimum 20-mile range per charge.

• Independent suspension on each wheel.

Beginning with a sketch, Figure 2, I could

illustrate my ideas on to a sheet of paper to

help me visualize my final design. From

here I was able to transfer my design into

SolidWorks.

Figure 2: Sketch of Concept Design

Didier Mejia Mechanical Engineering Portfolio

Figure 3: Leaning

To increase stability, my design allows for the vehicle to lean while steering into a curve like a motorcycle, Figure 3. To make this possible, I design a double plane four-bar linkage suspension system which accommodates for the leaning, steering, and independent suspension of each wheel found in the front. Figure 5 shows the double plane four-bar linkage suspension system.

Figure 5: Double Plane Four-Bar Linkage Suspension. Figure 4: Finite Element Analysis.

Finite element analysis was done an all the members to determine a factor of safety and to determine how much material was necessary for its given application. Figure 4 shows a computer program’s FEA scale drawing on one component of the CFAV.

Didier Mejia Mechanical Engineering Portfolio

Figure 4, Illustrates the rear suspension assembly. The rear suspension assembly allows both wheels to be independent of each which in turn allow the vehicle to lean while making a turn. In addition, the rear suspension gives the restoring force when the vehicle is leaning. In other words, it brings the driver back to a vertical position when the driver is leaning.

Figure 6: Rear Suspension System.

Figure 7: Profile View of Final Design.

Didier Mejia Mechanical Engineering Portfolio

2016-2017 Senior Design Project – JPL Zero-G Subscale Mechanical Offloader. For my Senior Design Project, my team had to design three subscale mechanical offloaders for JPL’s current Starshade. My contribution to this project was designing one of the three offloaders. My offloader was design to offload the Starshade’s Pedals. Figure 8 is a picture of the starshade deployment, the first 3 steps include the pedals deployment.

Figure 9 is a CAD drawing of my final design. My design met all of its requrements, infact it was well prased by JPL lead Engineer for being unique and original. A few features that make this desing unique are its cababiltiy to control the rate of deployment of the Starshade pedals and the fact that it is striclly mechanical. Figure 9: Final Design.

Didier Mejia Mechanical Engineering Portfolio

To deviate away from any electrical motors, I had to implement a unique planetary compound gear system which allows the Inhibiting Roller and double J-rail to have the same angle velocity. The planetary compound gear system is shown in Figure 10.

Figure 10: Planetary Compound Gear System.

I built a small-scale model out of

aluminum, wood, and 3D printed gears

that I designed to test my design. To my

success the small-scale model did a

good job doing what it was meant to do.

Figure 11 shows my small-scale

model.

Figure 11: Small Scale Model of Offloader

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