Repairability of Impact-Induced Damage in SMC Composites

Abstract

This study discusses the repairability of impact-induced damage in an SMC composite which is made of chopped glass fibers and polyester matrix. The impact resistance and notch sensitivity of the composite material are characterized by tensile and flexural tests. Equivalent hole sizes for impact-induced damage are identified through the comparisons between the residual strengths of composites with impact-induced damage and artificial circular cutouts. It is concluded that no damaged portion should be removed from the impacted composites; otherwise more damage could be introduced to the com posites. The damaged composites are then repaired with a technique combining resin in jection and reinforcing patches. The resin injection is performed to seal the matrix cracks which would otherwise result in high stress concentrations due to geometrical discon tinuity. The reinforcing patches are employed to compensate for the strength reduction due to fiber breakage. It is revealed from the experiments that the repair technique is very effi cient for restoring the tensile and flexural strengths of the composite after impact-induced damage.

Self-Healing Capabilities in Polymeric Materials: An Introduction to Techniques

“…Consider the "hot plate welding" in this technique polymer pieces are brought into close proximity of each other at temperature above the glass transition temperature of the material, and this was sustained for enough time until interdiffusion across the crack face occurs and restores strength to the material. It has been shown, however, that the weakest point in the material remains the location where weld took place and also it becomes the favourable site for future damage [1]. For laminate composites, "resin injection" is often used to repair damage in the delamination form.…”

Experimental Investigation of Polymeric Beam Under Elastic and Plastic Loads

“…This force can be mechanical, thermal or chemical, causing radiation or a combination of these factors [1]. According to this study, life efficiency and overall strength reduce when a structure is damaged or broken [2]. However, the type of damage also plays a significant role in adapting the repair mode for a particular structure, which often makes the overall process complex and time-consuming [3].…”

Self-Healing Materials Systems: Overview of Major Approaches and Recent Developed Technologies

“…One of the earlier healing methods for fractured surfaces was "hot plate" welding, where polymer pieces were brought into contact above the glass transition temperature of the material, and this contact was maintained long enough for interdiffusion across the crack face to occur and restore strength to the material. It has been shown, however, that the location of the weld remains the weakest point in the material and thus the favourable site for future damage to occur [2]. For laminate composites, resin injection is often employed to repair damage in the form of delamination.…”