Project Title: Shape Memory Alloy - Driven Quick Response Actuator

Project Team: Jon Brenneman, Scott Duncan, Seth Harrison, Jeff Kobelak

Background Information: A shape memory alloy is a material possessing remarkable elastic properties. This project employs a nickel – titanium alloy called Nitinol. Under the right conditions, a Nitinol wire that is stretched up to 8% strain can return to its original length.

Project Objective: The objective of the project is to determine material properties of Nitinol including the modulus of elasticity, yield strength, and strain recovery rate as functions of temperature.

Design: To obtain the desired properties of Nitinol, the team determined that the most accurate and versatile design is a modified tensile test. Shown to the right, the final design employs force transducers to measure wire tension, thermocouples to measure wire temperature, a rotational potentiometer to measure elongation, and a variable speed DC motor to turn a power screw that increases the applied load.

Results: Stress-strain curves are generated by varying the load at constant temperature. From these curves, the desired properties of Nitinol are calculated. Transition temperatures are found by varying the temperature at a constant load.

Date: Fall 2002
Faculty Advisor: Damian Rose - Mechanical Engineering Department, Penn State University
Project Sponsors: Dr. Michael Jonson - Penn State Applied Research Lab, University Park, PA
Dr. Gary Koopmann - Penn State University Center for Acoustics and Vibration, University Park, PA