Optimization of circular composite patch reinforcement on damaged carbon fiber reinforced polymer laminate involving both mechanics-based and genetic algorithm in conjunction with 3D finite element analysis

Abstract

Composites are significantly used in aerospace, automotive and civil structures due to their high specific strength, high stiffness, corrosion resistant and longer fatigue life. During service life, composite structures are susceptible to damage, which reduces their structural integrity. For extending its service life, the damage needs to be repaired. In case of low velocity impact damage adhesively bonded patch repair is found to be effective in extending the service life of damaged parts. The repair performance is mainly influenced by patch stacking sequence, patch shape, patch thickness, overlap length and adhesive thickness and its shear strength. In the present work, both numerical and experimental works are carried out to study the mechanics of composite patch repair on damaged carbon fiber reinforced polymer panel of configuration [45/−45/0/90]s subjected to tensile load. The influence of patch stacking sequence, patch thickness, adhesive thickness and overlap length on repair performance is investigated through a mechanics-based design approach involving finite element analysis. Stress concentration factor and shear stress in adhesive layer are considered to analyze the repair performance. Later, a genetic algorithm-based approach in conjunction with finite element analysis is implemented for arriving at an optimized patch dimension and adhesive thickness. Experimental study is then carried out with optimized geometry using non-contact optical-based technique namely digital image correlation. The strain field from digital image correlation is compared against the finite element results.

Digital Image Correlation Measurement of the Deformation and Failure in PBX Brazilian Discs Reinforced with CFRP Patches

“…The use of CFRP patches is an efficient and economic method for structural reinforcement. In addition to their excellent mechanical properties (e. g., high strength and stiffness), CFRP patches share multiple physical and chemical advantages (e. g., they are light weight, have great formability, and superior corrosion resistance); therefore, they are widely used in engineering fields, such as aerospace, automotive, and civil structures [22–28].…”

Assessment of local strain field in adhesive layer of an unsymmetrically repaired CFRP panel using digital image correlation

“…Around the circular hole there are 15360 elements (96 circumferential; 40 radial; 4 thickness). The meshing surrounding the hole is chosen based on mesh convergence study [34,35]. Every layer is meshed with one element in thickness direction for both patch and panel.…”

Flexural static and fatigue response of patch repaired laminated composites for different patch‐parent configurations

“…[ 19 ] Furthermore, the stresses produced in the repaired zone are also dependent on the adhesive and the patch thickness. [ 21 ] C. Soutis and F. Hu [ 22 ] reported that the patches with the edges tapered from inside result in localized thickening of the adhesive near the patch edges, leading to lower stress concentration in the adhesive layer. The stacking sequence of the parent laminate also influences the behavior of repaired system.…”