Elevated Temperature Lap Shear Testing of a Carbon Fiber Epoxy Composite Repair System Available to Purchase

Thermoplastic matrix materials will lose lap shear strength — among other properties — as they approach their glass transition temperature. The lap shear properties of these materials should be characterized to account for any change in temperature when designing composite repairs for leaking pipes. Not properly accounting for any decrease in lap shear strength at higher temperatures could cause the repair to be much shorter axially than required by the ASME PCC2 Article 4.1 standard, resulting in a potentially compromised repair. The results of this study showed that the lap shear strength of these two polymeric materials, a two part epoxy and cyanate ester, can decrease with increasing temperature. Also, this study confirms that epoxy bonds better to surfaces with a higher surface roughness, which is especially important in pipe repair applications with through wall defects.