Thermal Shock and Thermal Fatigue on Delamination of Glass-fiber-reinforced Polymeric Composites

Abstract

Glass-fiber-reinforced unsaturated polyester and epoxy resin composites were exposed to 75 C temperature gradient thermal shock for ten times in different stages of conditioning times. The other lot of short-beam shear specimens were conditioned with a thermal shock of again 75 C temperature gradient for the different cycles. The three-point bend test was performed on the conditioned specimens to evaluate the value of interlaminar shear strength. These conditionings may induce matrix cracking because of large misfit strain. The present experiments aim to study the fiber-matrix debonding effect of thermal shock-thermal fatigue, post-curing hardening phenomena of thermal conditioning, and also the mechanical keying factor of sub-zero conditioning.

Structural Integrity of Glass/Polyester Composites at Liquid Nitrogen Temperature

“…The residual stress distribution, differences in Poison's ratios and differential coefficient of thermal expansion can influence the crack multiplication stage of failure process. Here the presence of more interfaces [10] in the present composite strongly affected by cryogenic thermal shock. It may lead to generate more interfacial cracking.…”

Computational study on stress & deflections of glass epoxy composites

“…The eccentricity given at the hinge, δ = x*2.1mm = 9.5* 2.1mm = 20 mm 8 degree orientation. The maximum tensile occurs at (±0) 8 , orientation, minimum tensile stress at (±0) 8 .…”

“…Making use of experimental set up, deflection test is performed on the (± 0) 8 , (± 20) 8 , (± 30) 8 , (± 40) 8 , (± 45) 8 , (± 55) 8 ,(± 60) 8 specimens. As the total load could not be simulated on deflection test due to experimental setups geometrical constraints, the experimental results were extrapolated to estimate actual deflection.…”

Mechanical Behavior of Glass/Epoxy Composites at Liquid Nitrogen Temperature

“…Thus, the sign of improvement in the shear value after cryogenic conditioning is probably due to differential thermal contraction ( figure 3 and figure 4) of the matrix during sudden cooling which leads to the development of greater cryogenic compressive stresses and may increase the resistance to debonding and better adhesion by mechanical keying factor at the interface between fiber and the matrix [12,13].…”