Simulation and experimental validation of mixed mode delamination in multidirectional CF/PEEK laminates under fatigue loading

Abstract

a b s t r a c tCyclic mixed mode delamination in multidirectional composite laminates subjected to high cycle fatigue loading has been investigated by numerical simulations and cyclic mixed mode bending experiments. The numerical model includes lamina and interface elements. The description of the delamination crack growth rate is based on the cyclic degradation of bilinear interface elements linking the evolution of the damage variable with the delamination crack growth rate. The constitutive cyclic damage model is calibrated by means of mixed mode fatigue experiments and reproduces the experimental results successfully and with minor error. It is concluded that only with implementing a cyclic damage variable in the cohesive interface element the experimentally observed crack growth and stiffness degradation can be captured properly. Scanning electron microscopy of fracture surfaces after cyclic loading revealed that abrasion of crack bridging surface roughness is the main microscopical cause of weakening and degradation of the interface.

Mode I fatigue and fracture behavior of adhesively-bonded pultruded glass fiber-reinforced polymer (GFRP) composite joints

“…Extensive research efforts were also devoted to the investigation of the FCG under Mode I (Costa, Mahdi, Vicens, Blanco, & Rodríguez-Bellido, 2009;Hojo, Matsuda, Tanaka, Ochiai, & Murakami, 2006;Shivakumar, Chen, Abali, Le, & Davis, 2006;Walls, Bao, & Zok, 1993), Mode II (Arg€ uelles, Viña, Canteli, & Bonhomme, 2010;Tanaka & Tanaka, 1997), and mixed-mode fracture (Naghipour, Bartscha, & Voggenreitera, 2011;Shahverdi et al, 2013a;Zhang, Vassilopoulos, & Keller, 2009) of composite joints under fatigue loading. Instead of the SeN curves, FCG curves are used to represent the fatigue behavior and also to provide information concerning the developed damage in terms of crack or cracks that propagate during fatigue loading.…”

Fracture Mechanics Analyses for Interface Crack Problems - A Review

“…The modeling of an existing crack or flaw as required for VCCT to model the crack tip is not necessary in this approach. An extension to include modeling of fatigue crack growth under cyclic loading was recently presented by Naghipour et al [58].…”

Microscale Modelling of Fiber-Matrix Debonding of SiC/Ti-15-3 Laminates under Cyclic Loading

“…It is worth mentioning that the same parameters for the matrix (epoxy 8552), fiber (carbon), and interface, obtained partially from available sources in literature and authors' previous experimental results 8 , were used in GMC and the FEM simulation (see Table. 2). The user-developed cohesive element in FEM has been demonstrated the reliable and predictive capability to capture the cyclic delamination growth according to Naghipour et al 8 and therefore was used as a validation tool. A comparison of the GMC and FEM results is presented in Figure. 5.…”

“…This physical phenomenon is represented mathematically by incorporating the successive evolution of the debonding compliance with number of cycles (with the help of Paris-type cyclic crack/debonding growth law). The Paris-type fatigue debonding law has been successfully implemented by Naghipour et al 8 within the context of FE cohesive zone formulation to simulate the inter-laminar delamination of composites.…”