Temperature effect on the static mode I delamination behavior of aerospace‐grade composite laminates: Experimental and numerical study

Abstract

Aerospace structures are exposed to high‐temperature conditions during service. In‐depth study for the temperature effect on composite interlaminar properties is important for the structural design and reliable application. In this study, mode I delamination behaviors at different temperatures are investigated, to understand the effects of temperature on the delamination growth process, including fracture toughness, bridging stress, and failure mechanism. It is found that R‐curve behavior presents at all temperatures. The initial and steady‐state fracture toughnesses exhibit linear increase trends with the increase of the temperature, from which equations are established to predict the initial and steady‐state fracture toughnesses at other temperatures. More bridging fibers are observed at higher temperatures, and the resulted fracture resistance at 130°C is 136.9% higher than that at room temperature. The maximum bridging stress also increases with the increase of temperature. A numerical framework based on the cohesive zone model is established for delamination modeling. Material parameters at various temperatures are obtained by an exponential model. Suitable values of interfacial parameters in cohesive elements are numerically determined. Predicted load–displacement responses agree well with the experimental ones, illustrating the applicability of the proposed numerical method.

Estimation of cohesive zone model parameters for glass/Elium composites with different processing temperature

“…Tables 2 and 3 display three pairs of cohesive parameters (interface stiffness and strength) that correlate to a tested fracture energy release rate. The estimated interface stiffness and strength of RT, 50°C, and 80°C laminates were in the range of 10 5 -10 6 MPa/mm and 30-100 MPa, 8,[14][15][16][17][22][23][24][25][26] respectively.…”

“…In order to accurately define the delamination behavior of composite, the cohesive zone model (CZM) is used to simulate the delamination behavior of composites. [7][8][9] Heidari-Rarani et al 10 discussed the benefits, drawbacks, and challenges of various approaches for simulating delamination growth and discovered that the extended finite element method-cohesive zone model was an effective approach. The CZM, known as the fictitious crack or Dugdale-Barenblatt model, 11,12 was first proposed by Dugdale and Barenblatt to describe nonlinear fracture processes.…”

“…These values are typically obtained through trial and error method. 8,[14][15][16][17][22][23][24][25][26] It was discovered that all research appeared to concur on interface stiffness between about 10 4 and 10 6 N/mm 3 . Therefore, a trial and error approach was also used in the current work to get adequate values of the interface stiffness and interface strength.…”

ModeIIIfracture of composite laminates with elastic couplings in edge ring crack torsion test

“…Temperature effects on the mode I and mode II delamination behavior in CFRP laminates were also investigated. [13][14][15] Liu et al 16 proposed an improved fatigue delamination model to characterize the effect of fiber bridging and stress ratio on the mode II delamination in multidirectional laminates. Quasi-static and fatigue tests of mixed mode I/II delamination in composite laminates with various mode mixities were performed in References 17-20.…”

“…Gong et al 4 proposed a semi‐analytical model with a clear correlation with the interfacial angles to determine the mode II fracture toughness of multidirectional laminates. Temperature effects on the mode I and mode II delamination behavior in CFRP laminates were also investigated 13–15 . Liu et al 16 proposed an improved fatigue delamination model to characterize the effect of fiber bridging and stress ratio on the mode II delamination in multidirectional laminates.…”