Concept Sketch Spring Lock

We are considering how we plan to apply the rotating load. We think the most adjustable and clean way is to use a spring locking force applicator. This will eliminate messy wiring and complicated linkages.

This sketch shows the basic assembly and function. The spring compression can be adjusted with a screw, pushing more or less on the plunger with roller attached.

This sketch shows how the spring roller assembly would fit on the overall rotating assembly.

Centrifugal Concept Sketch Video

Here's another video sketch explaining one of our concepts in more detail.

Rough Concept Sketches

We have generated several concepts that have a lot of potential. They're shown here in rough sketches.

Piezoelectric actuators will be mounted around the composite disc. These actuators will fire off in sequence in a rotational motion. This will simulate a rotating load without the need for actual rotation.

This method involves using a linear actuator and a series of linkages to transfer a vertical force to a horizontal force that acts on the circumference of the disk. This allows the electrical wires needed to operate the actuator to remain fixed while the linkages spin.

This horizontal design was inspired by the orientation of a lathe to keep the system stable at high speeds.

This concept utilizes the centrifugal forces that are in effect at high rotational speeds. This concept uses a purposeful unbalance to apply a load to the disc. The limitation is that it is difficult to control the load magnitude because it has 3 variables that effect it. It will need to be very fine tuned. 

Communications Problem Definition

The problem has been defined. We are working remotely with Dr. Kohlman so ease of communication isn't ideal. So I have made a video that details out the problem definition to be sure we are on the same page.

This proved to be a very effective communication tool.

Project CRoFT Overview

Hello

We are a Senior Design team from Drexel University that is working with NASA Glenn Research Center. We are tasked to design a Composite Rotary Fatigue Tester (CRoFT). The team members are Timothy Chua, Dylan Paproski, Joseph Rappazzo, and Nikhil Tandon. Under the supervision of Dr. Leslie Lamberson and guidance of our NASA contact, Dr. Lee Kohlman, we will design and build a prototype rotary composite fatigue tester.

Composite materials are often utilized to reduce the weight in structural components. In this case, the composite material serves as the web of a gear between the metal hub and the teeth of the gear. In drive train applications of these gears, there are radial vectors and overturning moments applied to them which cause fatigue. Our goal is to prototype a testing machine that will simulate these rotating loads.

The specifications of this project are to design a test fixture that will have the composite gear undergo a radial load vector with an amplitude of 300 pounds while operating the test machine at a rate of 5000 rotations per minute. The second goal of this project is to have 5x the rpm of the original speed in order to achieve accelerated fatigue testing. While the disc is undergoing these conditions, the deformation of the disc is to be measured. The last goal that is trying to be accomplished is to generate a rotating overturning moment on the composite disc without rotating the test article. 

This description is the current overview of the project and with the help of our adviser and NASA contact, we are looking to design an effective test fixture that will satisfy all these goals, and help with the development of hybrid composite gears.

-Team CRoFT