Thermo-mechanical stress relief analysis in PMMA and 6000 series aluminum

Stress relief of materials produced in bulk is a key part of the manufacturing process. The most common kinds are either thermal or mechanical and are commonly applied to commercial metal alloys. A third type, thermo-mechanical, utilizes thermal gradients to induce residual stresses of an equal and opposite nature to balance compressive and tensile stresses existing in the material after solutionizing. The experiment detailed in this work shows the effect of thermal gradients on residual stresses in polymethyl methacrylate (PMMA). A downhill quench from 95 C to 15C is able to create a deflection of 2.36 millimeters, evidence of residual stress. A subsequent uphill quench from -40 to 100 degrees reduced the deflection by 37 percent. The finite element simulation of a 6000 series aluminum block verifies that under properly controlled processing parameters, it is possible to induce opposite stresses to relieve residual stresses in a quenched material. Additional limitations to the uphill quench technique are detailed in the following work so that thermo-mechanical stress relief may be properly applied to a range of materials.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2014

Author dc:creator

• Stephens, Scott, S.B. (Scott A.). Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Thomas W. Eagar.

• Materials Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/89983

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/89983