2012 SURF: Stress and Material Properties Analyses

Stress Analysis and Material Properties Determined With Various Techniques

Undergraduate Research Fellow: Jacob Finley, Mechanical Engineering

Mentor: Dr. Mehrdaad Ghorashi, Engineering Department

The purpose of these experiments was to determine the material properties and to perform stress analysis of several specimens made of metals and polymers. This activity was mostly successful and was accomplished using different, but related test setups. Qualitative determination of residual stresses in the polymer specimen was accomplished using cross polarized fluorescent light that displayed stress fringe patterns via birefringence.

Using strain gauges attached to flat bars and round tubes made of aluminum 6061 alloy, 304 stainless steel round tube, C1018 cold-rolled steel, and A36 hot-rolled structural steel that were loaded in bending, strain results were obtained.  They were then used in corresponding equations to provide the modulus of elasticity and in some cases the Poisson’s ratio of the mentioned materials.  The obtained results were then compared against available data for these materials. Additionally, utilizing ASTM E-8 standard, tensile test samples were cut and tested in the Instron 5882 universal testing machine to determine mechanical properties like modulus of elasticity, yield strength, tensile strength, and rupture point. Finally, another test setup was built for demonstrating Maxwell’s Reciprocity theorem.

Start Slideshow

Stress Analysis 1: Set-up The undergraduate research fellow designed and constructed testing devices. View Full-Size	Stress Analysis 2: Birefringence Residual stress patterns displayed by polarized light in a French curve. View Full-Size
Stress Analysis 3: Nondestructive testing Load was applied to samples made of various materials to induce bending. View Full-Size	Stress Analysis 4: Analyzing Tubes Torsion and bending were applied to open and closed tubing, strain was measured. View Full-Size
Stress Analysis 5: Deflection A test setup with load was built to demonstrate Maxwells reciprocity theorem. View Full-Size	Stress Analysis 6: Destructive testing Tensile strength of flat bars was tested on Instron universal testing machine. View Full-Size