ETME360 Spring Semester 2014
E-Problem
8a

Piezoelectrics: Ultrasonic Applications
R. Larson

1. Ultrasonic non-destructive testing (NDT) techniques are used to evaluate material properties of an unknown metal alloy sample, of density ρ = 0.29 lb/in³ . Longitudinal sound velocity for the 10 MHz signal is measured at 3.08 X 105 inches/sec, and shear (transverse) velocity is measured at 1.19 x 105 inches/sec.  Find Poisson’s ratio, Young’s Modulus, and Shear modulus for the sample based on these test results.

 

 2.  Bonus! The sample is non-radioactive, legally obtained - but costly. It has a silvery appearance, and seems to be non-reactive. The specimen will not melt in the lab's best heat treatment oven, even at the highest settings. (Oven is capable of reaching temperatures of around 1250°C.) The sample has proven difficult to machine, evidently due to work hardening; the material tends to plastically deform on the second pass of a cutter.

Perform any research necessary to identify this metal alloy sample based on the information provided and comparisons of density and calculated Young’s Modulus to published values. Cite the source of comparison data using proper citation methodology.