General mixed mode I/II failure criterion for composite materials based on matrix fracture properties

Fakoor, Mahdi; Khansari, Nabi Mehri

doi:10.1016/j.tafmec.2018.06.004

Cited by 20 publications

(3 citation statements)

References 43 publications

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“…Due to the formation of a significant fracture process zone in the crack-tip vicinity of the composite materials during the delamination propagation, the experimental measurements of the mode II delamination test data always present some difficulties and scatters [38]. For this reason, an idea is evolved to determine the mode II fracture toughness without carrying out experimental tests.…”

Section: Prediction Of the Initial And Steady-state Fracture Toughnesmentioning

confidence: 99%

R-curve behaviour of the mixed-mode I/II delamination in carbon/epoxy laminates with unidirectional and multidirectional interfaces

Gong

Zhang

Zhao

et al. 2019

Composite Structures

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To successfully predict the delamination behaviour of the laminated composite structures with fibre bridging, the R-curve has to be studied. This work experimentally investigates the complete R-curve behaviour of the unidirectional and multidirectional carbon/epoxy composite laminates. The delamination tests use the double cantilever beam (DCB), mixed-mode bending (MMB) and endnotched flexure (ENF) specimens for mode I, mixed-mode I/II and mode II loading, respectively. The test results show that the interfacial ply and mode mixity (φ-ratio) have significant influences on the initial fracture toughness, steady-state fracture toughness and fibre bridging length. The ratio between the steady-state fracture toughness and its initial value is approximately same for both interfaces, which indicates a similar enhanced effect of the fibre bridging on the fracture toughness. The Benzeggagh-Kenane (B-K) criterion is capable of representing the relation between the fracture toughness and the φ-ratio. Based on the DCB and MMB test results, the predicted values of the mode II fracture toughness via the B-K criterion are very close to the experimental ones, which illustrates

show abstract

Section: Prediction Of the Initial And Steady-state Fracture Toughnesmentioning

confidence: 99%

R-curve behaviour of the mixed-mode I/II delamination in carbon/epoxy laminates with unidirectional and multidirectional interfaces

Gong

Zhang

Zhao

et al. 2019

Composite Structures

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show abstract

“…Based on Van der Put's theory, Fakoor et al proposed a new concept called the "reinforcement isotropic solid" (RIS) model for assessment of crack behavior of orthotropic materials under mixed-mode I/II loading [40][41][42]. The main assumption of the RIS model is that orthotropic material is considered as an isotropic material that is reinforced with fibers.…”

Section: Introductionmentioning

confidence: 99%

Applying the new experimental midpoint concept on strain energy density for fracture assessment of composite materials

Khaji

Fakoor

Farid

et al. 2022

Theoretical and Applied Fracture Mechanics

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“…Fakoor and Ghoreishi [ 13 ] conducted a comprehensive survey on stress intensity factors in rotating disks having semi-elliptical cracks. Moreover, Fakoor and Khansari [ 14 ] proposed a general criterion, based on linear elastic fracture mechanics (LEFM), for a fracture analysis of orthotropic materials under mixed-mode I/II loading for the case of the misalignment of fibers with respect to the loading direction. Tschegg et al [ 15 ] studied the mixed-mode I/II fracture of spruce wood.…”

Section: Introductionmentioning

confidence: 99%

Tensile-Tearing Fracture Analysis of U-Notched Spruce Samples

et al. 2022

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Spruce wood (Picea Mariana) is a highly orthotropic material whose fracture behavior in the presence of U-shaped notches and under combined tensile-tearing loading (so-called mixed-mode I/III loading) is analyzed in this work. Thus, several tests are carried out on U-notched samples with different notch tip radii (1 mm, 2 mm, and 4 mm) under various combinations of loading modes I and III (pure mode I, pure mode III, and three mixed-mode I/III loadings), from which both the experimental fracture loads and the fracture angles of the specimens are obtained. Because of the linear elastic behavior of the spruce wood, the point stress (PS) and mean stress (MS) methods, both being stress-based criteria, are used in combination with the Virtual Isotropic Material Concept (VIMC) for predicting the fracture loads and the fracture angles. By employing the VIMC, the spruce wood as an orthotropic material is modeled as a homogeneous and isotropic material with linear elastic behavior. The stress components required for calculating the experimental values of notch stress intensity factors are obtained by finite element (FE) analyses of the test configuration using commercial FE software from the fracture loads obtained experimentally. The discrepancies between the experimental and theoretical results of the critical notch stress intensity factors are obtained between −12.1% and −15% for the PS criterion and between −5.9% and −14.6% for the MS criterion, respectively. The discrepancies related to fracture initiation angle range from −1.0% to +12.1% for the PS criterion and from +1.5% to +12.2% for the MS criterion, respectively. Thus, both the PS and MS models have good accuracy when compared with the experimental data. It is also found that both failure criteria underestimate the fracture resistance of spruce wood under mixed-mode I/III loading.

show abstract

General mixed mode I/II failure criterion for composite materials based on matrix fracture properties

Cited by 20 publications

References 43 publications

R-curve behaviour of the mixed-mode I/II delamination in carbon/epoxy laminates with unidirectional and multidirectional interfaces

R-curve behaviour of the mixed-mode I/II delamination in carbon/epoxy laminates with unidirectional and multidirectional interfaces

Applying the new experimental midpoint concept on strain energy density for fracture assessment of composite materials

Tensile-Tearing Fracture Analysis of U-Notched Spruce Samples

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