Sheet Metal Fatigue Fixture

The goal of the project is to design and fabricate a fatigue fixture that can determine the fatigue-life (S-N) curve for a given sample.

=Problem Definition= The purpose of this project is to create a fully reversible fatigue fixture that can test the fatigue life of a given sample. With this data, we should be able to create an S-N curve for the sample. These given samples can be bent, heat treated or etc. prior to testing.

Background
SEL products are exposed to various cyclic stresses during their service life. These stresses are the result of thermal cycling, vibration, and direct loading. Sheetmetal, due to its non-isotropic grain structures, will have unique fatigue properties depending on part geometry. Hence, the S-N curves for specific sheetmetal materials are not commonly available. SEL products are rated for abnormally long life; therefore, it is important to know the S-N curves of given materials to predict the life of a product.

Fatigue testing requires multiple sample runs and each run takes a long time. To allow this, the fixture needs to be able to operate safely unattended. An ideal design will be optimized for quick setup, ease of use, cost of implementation, and repeatability.

Deliverables
We have to deliver a final design fatigue fixture that can accomplish everything on the specifications list, but most importantly it most be able to create a S-N curve with very little human interaction.

Specifications
The final product should have these considerations in mind:
 * Handle up to 40 ksi of Static Stress.
 * Overall Height, Width and Length shouldn't surpass 60 inches, 36 inches and 36 inches respectively.
 * Can find an S-N curve of a sample at a minimum of 1 inch by 0.5 inches and a maximum of 6 inches by inches.
 * Any material should be able to be tested, but specifically aluminum and plastic.
 * Should be able to fit on a desktop.
 * The fixture shouldn't surpass 70 pounds in weight.
 * Eliminate all pinch points on the fixture.
 * Setup Time for the fixture cannot exceed 45 minutes.
 * User interface must be easy to view and interact with.
 * Must be able to configure the operating force and frequency for a run.
 * Must be able to run without continuous human interaction for a long period of time.
 * The software must be able to generate an S-N curve using the results of the test runs.
 * Control System must be able to detect when a failure occurs during the run.
 * Operational noise cannot exceed 80 decibels.
 * The frequency range that we must meet must be 1-100 Hz.
 * Range of error cannot exceed 15%.
 * Peak power load cannot exceed 1500W.
 * Fixture must cost under $2,000.
 * Fixture must be fully and partially reversible.
 * Must be able to run from a wall socket.

=Design Considerations=

=Project Learning= Decision Matrix's for the Fixture and Motor

Comparison of Failure Detection Methods

Axial Stress Calculations

Comparison of Loading Methods

Motor Linkage Power Required Analysis

Displacement Driven Cam Idea Folder

Fixed Displacement Idea Folder

Motor Linkage Idea Folder

=Final Design=

=Validation=

=Team Members=

=Additional Documentation=

Project Schedule

Gantt Chart

Meeting Minutes

Meeting Minutes Folder

Presentations

Snapshot 1 Presentation

Client Interview

Client Interview w/ SEL

Budget

Budget