Critical strain energy release rate of woven carbon/epoxy composites subjected to thermal cyclic loading

Abstract

In the current study, experimental and numerical approaches were adopted to investigate the effect of thermal cyclic load on the delaminated beam behavior of woven carbon/epoxy laminated composites. For this purpose, composite specimens were prepared according to ASTM standard and subjected to 175 thermal cycles in the range of −30 to 60°C before conducting the mode I and mode II interlaminar fracture tests. Experimental results revealed that thermal cycles lead to a drop in maximum loading capacity of the delaminated beam as well as the interlaminar fracture toughness of the woven carbon/epoxy composites. The beam fracture toughness at initiation and propagation decreased by 8% and 12% under mode I loading and by 13.84% and 15.64% under mode II loading, respectively. In the numerical analysis, the cohesive zone model was utilized in order to predict the global response of the delaminated beams. The micro and scanning electron microscope images of fracture surfaces provide efficient insights into the identification of the main mechanisms contributing to decreasing fracture toughness under cyclic thermal load. These images show that specimens subjected to cyclic thermal load exhibited smoother surfaces, which could be due to weaker bonding between matrix and fibers after cyclic thermal loading.

Direct measurement and verification of cohesive zone model parameters for basalt/PProds using the transverse tensile test and virtual double cantilever beam test

“…A typical evaluation method of a fracture energy of mode-I is the double cantilever beam (DCB) test. [30][31][32][33][34][35] Many studies conducted the DCB test for the rectangular specimen of the laminate composites. On the other hand, there is no report using the test for the rod shape specimens.…”

Fiber bridging mechanism in moisture‐induced mode I delamination in carbon/epoxy composites: Finite element analysis and experimental investigation

“…[ 34 ] Furthermore, by proposing a modified cohesive zone length model, Esmaili and Taheri‐Behrooz [ 36 ] improved the crack growth rate prediction in AS4/PEEK composites at various mode ratio I/II ratios, including pure mode I and II. Not only that, Sabaghi et al [ 37 ] discovered that upon 175 thermal cycles within −30 to 60°C, both initiation and steady‐state fracture toughness of woven carbon/epoxy composites were deteriorated under mode I and mode II loadings. BTS law was found to well simulate the force‐displacement curves for both mode I and mode II cases when the steady‐state fracture toughness was used in the simulations.…”

Thermal cycling of strained nickel‐coated glass‐epoxy composite laminates: Effects on macro mechanical and fiber‐matrix interface properties

“…It is considered that the fiber-matrix interface has a strong influence on the environmental durability of fiber reinforced polymer composites. [30][31][32] Sabaghi et al [33] subjected carbon fiber epoxy composite to thermal cyclic mode I loading and they observed some smoother fracture surfaces, pointing to a deteriorated fiber-matrix interface. The addition 0.1 wt% CNT to glass fiber epoxy composite was detrimental under hydrothermal cycling, explained by additional interfacial debonding at CNT-epoxy interfaces.…”