Study on impact resistance and parameter optimization of patch-repaired plain woven composite based on multi-scale analysis

Patch-repaired plain woven composite structures were exposed to internal damage caused by impact during service, which reduced mechanical properties. A multi-scale modeling strategy was proposed to study the impact resistance characteristics of patch-repaired plain woven carbon-fiber-reinforced-polymer (CFRP) laminates. The micro representative volume element (RVE) was extracted from the yarn; a local homogenization method was used to obtain the equivalent cross-ply laminate (ECPL) cells corresponding to the mesoscale RVE. The finite element model (FEM) of patch-repaired plain woven laminate was established by extending the ECPL cells. The FEM was checked by the low-velocity impact (LVI) tests, and the impact parameter errors were within 10%. Furthermore, impact resistance of repaired specimens under different impact conditions (e.g., the impact energy was 3 similar to 20 J) was studied. Finally, patch parameters (patch thickness, patch size, off-axis angle) of the repaired specimen were optimized by multi-objective optimization based on the surrogate model and response surface method (RSM). After multiobjective function optimization, the optimal patch parameter configuration (the thickness of the patch was 0.87 mm, the diameter was 66 mm, and the off-axis angle was 44.2 degrees) reduced the absorbed energy value of the repaired specimen from 4.9089 to 4.1640 J, and the delamination area of the repaired specimen from 605 to 280 mm(2). All the results provide a reference for patch repair of plain woven composites.

Automated summary

A multi-scale modeling strategy was used to study the impact resistance of patch-repaired plain woven carbon-fiber-reinforced-polymer laminates. The finite element model of the patch-repaired laminate was established and verified through low-velocity impact tests. The impact resistance of the repaired specimens under different impact conditions was studied, and patch parameters were optimized through multi-objective optimization.