Hope
College Engineering Department
Research Experiences for Undergraduates
Summer 2008
Project Summary
Research Experiences for Undergraduates
Summer 2008
Project Summary
|
Hope
College Engineering Department Research Experiences for Undergraduates Summer 2008 Project Summary |
| Project Title: | Performance Evaluation of FRP Composites Using Infrared Thermography |
| Student Name: | Joel Blok |
| Student's Home Institution: | Hope College |
| Research Advisor: | Dr. Jeff Brown |
| Source of Support: | This material is based upon work
supported by the
National Science
Foundation under NSF-REU Grant
No. PHY-0452206, Hope College Engineering Department, Howard Hughes Medical Institute,
and the |
Reinforced concrete (RC) beams are designed to allow minor concrete cracking in the tension zone. The severity of cracking in a beam element is an excellent performance indicator. FRP composites are widely used to increase the flexural and shear capacity of RC elements, but there is a potential disadvantage. Strengthened surfaces are no longer visible and cracks or delaminations that result from excessive loading or fatigue may go undetected. This research investigated thermal imaging techniques for detecting load-induced cracking in the concrete substrate and delamination of the FRP composites. A pixel normalization technique was used to enhance detectability and characterization of this damage. After preliminary fatigue testing on steel rebar specimens, a standardized test protocol was developed. Three RC specimens, one with fabricated delaminations, were loaded monotonically. While the first failed almost immediately after delaminations were detected, some defect propagation was clearly evident during thermal analysis on the second and third.
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