Strain rate effects on the thermomechanical behavior of glass/polyester composite joints

For several decades, composite materials have been used in different applications due to their multiple advantages. It has become necessary to understand the dynamic behavior of these materials under critical loads. In-plane (IP) and out-of-plane (OP) dynamic compression tests were investigated on a cubic specimen of composite joints under low to high strain rates using the Split Hopkinson Pressure Bars (SHPB) technique. The specimens consist of two adherents (glass/polyester composite) assembled by an adhesive with different thicknesses (1 and 2 mm). During the experimental tests, the high-speed camera was used to check the damage history and the failure mechanisms on adhesively bonded composite joints. The sample surface temperatures were monitored using an infrared camera (IR). For bonding of two composite substrates, it can be noted that the thickness of the adhesive has a significant effect on the dynamic behavior and the kinetics of the damage. It has been concluded that the damage was localized at the level of the layers in the case of in-plane loading and the level of the adhesive zone in the case of out-of-plane loading. The thermomechanical behavior of cubic specimens of adhesively bonded joints subjected to dynamic compression has been studied. The results underline the sensitivity of the dynamic behavior of the adhesively bonded joints to the strain rate, the loading direction and the appearance of heat dissipation linked to the increase in temperature following the initiation of damage. This rise of temperature can dangerously approach the glass transition temperature of the matrix.

Automated summary

This study conducted dynamic compression tests on composite joints using the Split Hopkinson Pressure Bars (SHPB) technique, finding that the thickness of the adhesive significantly influences the damage kinetics and its localization. The dynamic behavior of adhesively bonded joints is sensitive to strain rate, loading direction, and temperature increase linked to damage initiation.