2012 SURF: Thermo Elastic Effect in Polymers

Thermo Elastic Effect in Polymers

Mentor: Dr. Jim Smith, Engineering Department

A polymer is a large molecule (macromolecule) composed of repeating structural units.  These sub-units are typically connected by covalent chemical bonds.  Although the term polymer is sometimes taken to refer to plastics, it actually encompasses a large class of compounds comprising both natural and synthetic materials with a wide variety of properties. 

Polymers are widely used in many industries.  Some polymer materials in certain industries are exposed to millions of low level stresses in their lifetime.  Fatigue occurs when a material is subjected to repeated loading and unloading.   These stresses generate microscopic cracks which finally cause the material to fracture before it reaches its maximum stress. 

In order to evaluate the life span of polymers, a low-stress fatigue process was employed and a high-speed and high-sensitivity thermal imaging graphic camera was used to detect the temperature evolution caused by the damaging process.  After a period of cyclic stress, the material generates heat and dissipates energy.  The camera allows these affected areas to be seen long before the polymer breaks. The essence of thermography in this project is to identify where the fracture will occur as early as possible.

Start Slideshow

Thermo Elastic Effect 1: Applied Stress A mechanism was built that uses hydraulic power to apply repeated stress. View Full-Size	Thermo Elastic Effect 2: Fabrication To eliminate shifting of the polymer, a special holding bracket was fabricated. View Full-Size
Thermo Elastic Effect 3: Photography A thermal imaging camera was set up to take repeated photographs of the polymer. View Full-Size	Thermo Elastic Effect 4: Temperature Pixel temperature was used to indicate the amount of stress imposed on polymer. View Full-Size
Thermo Elastic Effect 5: Analysis Mathematical analysis was performed on the images from the camera. View Full-Size	Thermo Elastic Effect 6: Imaging Thermographic images show the temperature evolution of applied stress. View Full-Size