Compressive fatigue behavior of external patch repaired carbon/epoxy composites

Abstract

This work involves an experimental investigation of the external patch repaired woven carbon fiber-reinforced polymer laminates under load controlled constant amplitude compressive fatigue loading. The specimens of parent laminates with stacking sequence [0/45] s and [45/0] s were both repaired with two types of precured patches viz. [0] 2 and [45] 2 representing high stiff and low-stiff cases. Digital image correlation and acoustic emission were employed to obtain the insight to the development of distinctive failure modes.The observations during the tests reveal a slow increase in the displacement for most part of the life followed by a rapid increase in the displacement signifying the failure due to fatigue. The examination of failed specimens reveal failure through hole for drilled (with hole) specimens compared to failure away from repaired zone indicating the significant reinforcement provided by external patch repair under cyclic loading. From life aspect, the drilled specimens possess a significantly lesser life (zero to few hundred cycles) compared to the patch repaired and pristine specimens (of order of few thousand cycles) highlighting the suitability of the external patch repair to restore the fatigue performance under compressive loading.

In situ resin‐injection approach for repairing barely visible impact damaged carbon‐fiber reinforced epoxy laminates: Optimizing the repair parameters using Taguchi method

“…Drilling several small circular holes at the BVID area could result in a cascading effect on the repair performance, as the drilling action could aggravate the BVID. [34][35][36] Our past studies revealed that drilling holes could result in diminution of laminate properties value (namely fracture strength, fracture strain, resilience, and fracture toughness) but no trend was observed with increasing VH numbers. [21,37] Furthermore, there was no effect of hole-hole orientation (row of holes parallel/perpendicular to the applied load direction) and hole-hole separation distance (where the VHs were confined within the BVID region) on the mechanical properties.…”

A parametric study on patch repaired quasi‐isotropic laminate in high‐velocity impact environment: Experimental and numerical investigation

“…The authors reported the low stiff patch [45] 2 and repairing the load‐bearing plies of parent laminate ([0/45] s ) showed the highest load recovery. Bhatia and Arockiarajan 27,28 also analyzed the effect of patch stiffness and parent laminate stacking sequence in compressive and flexural static and fatigue loading cases. The authors reported that the effect of stiffness is not pronounced in these loading cases.…”

Shear performance assessment of repaired honeycomb sandwich composite panels: An experimental and numerical study

“…This repair technique for laminated plates could serve as a reference for repairing honeycomb sandwich structures. Bhatia and Arockiarajan 10 conducted compressive fatigue tests on the repaired woven CFRP laminates, and the results showed that the external patch repair restored the compressive fatigue performance of the specimens. Mahdi et al 11 conducted four‐point bending tests on undamaged and repaired sandwich beams.…”