Damage mechanisms in CFRP/HNT laminates under flexural and in-plane shear loadings using experimental and numerical methods

Alkhateab, Baidaa; Tabrizi, Isa Emami; Zanjani, Jamal Seyyed Monfared; Rahimi, Mohammad Naqib; Poudeh, Leila Haghighi; Kefal, Adnan; Yıldız, Mehmet

doi:10.1016/j.compositesa.2020.105962

Cited by 17 publications

(12 citation statements)

References 49 publications

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“…According to a previous research by the authors, the start of nonlinearity at inplane shear test of the glass fiber reinforced epoxy matrix laminates indicated accumulation and further saturation of microdamage such as transverse cracks, delamination, and fiber rupture/breakage in the V-notch region. [22][23][24] As seen in Figure 3(F), such a transition is well presented by drawing two fitting lines at the linear and nonlinear sections of the curve and attributing the stress level of the intercept point between the two lines as the microdamage initiation stress. As seen in the inset plot of Figure 3(F), intercept points for all curves showed the same stress level.…”

Section: Shear Strain Calculation Through Dicmentioning

confidence: 69%

Using digital image correlation for in situ strain and damage monitoring in hybrid fiber laminates under in‐plane shear loading

et al. 2021

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Utilizing resistive strain gauges for V-notch shear tests in fiber reinforced laminates is usually limited to low strain values due to technical uncertainties imposed by the measurement technique and also the progressive damage development in the notched region of the composite. Therefore, this study investigates an alternative approach by using digital image correlation system and further comparison with resistive strain gauge to identify the effect of heterogenous nature of damage development on measurement results. Moreover, glass/carbon fiber hybrid and non-hybrid laminates are tested in two major directions through the same approach to determine the effect of stacking sequence in spatial microdamage accumulation. It is shown that tailoring appropriate region of interest for full field strain measurement at various stages of loading enables proper monitoring of microdamage accumulation and thereby delivers a precise stressstrain behavior for hybrid and non-hybrid laminates. Comparison of the strain maps for hybrid laminates tested in 0 direction, shows that the presence of carbon plies at the surface results in uniform strain distribution between the notches of the test sample. In contrast, a non-homogeneous strain map with separate regions of high strain gradient are observed for hybrid specimens with glass plies at surface, which can cause underestimation of average shear strain by resistive strain gauges. On the other hand, it is shown that strain maps for hybrid samples tested at 90 configuration is analogous regardless of the stacking sequence, and damage accumulation in these samples is most likely related to relative volume fraction of various fibers in hybrid laminate.

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Section: Shear Strain Calculation Through Dicmentioning

confidence: 69%

Using digital image correlation for in situ strain and damage monitoring in hybrid fiber laminates under in‐plane shear loading

et al. 2021

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“…the slopes of curves based on strain gauge for 13C and 1C specimen show vivid difference as compared to those of FGBs and DIC from the early stages of the test. Variation of slope in stress-strain curve is related to damage accumulation and consequent stiffness reduction inside the laminate (AlKhateab et al., 2020; Tabrizi et al., 2019b), and depending on the size of the damage inside the composite its influence zone will vary. According to global load sharing model (Swolfs et al., 2015) at locations far enough from the failure region (break influence zone) stress levels will be equal to the nominal level of stress in the test specimen, thereby it can be said that local strain measurements might not be influenced by damages occurring far away from them.…”

Section: Resultsmentioning

confidence: 99%

“…(2020) have used thermography and strain measurement techniques to comprehensively analyze the failure progress in multi-directional carbon fiber reinforced laminates. Alkhateab et al. (2020) have highlighted the complementary effect of using thermal maps in enhancing the capability of failure detection and damage accumulation in laminated structures.…”

Section: Introductionmentioning

confidence: 99%

“…In a recent study, Khan et al (2020) have used thermography and strain measurement techniques to comprehensively analyze the failure progress in multi-directional carbon fiber reinforced laminates. Alkhateab et al (2020) have highlighted the complementary effect of using thermal maps in enhancing the capability of failure detection and damage accumulation in laminated structures. A recent study successfully showed the ability of thermography to reveal the effect of embedded shape memory alloy wires on damage shape and failure progress in sandwich panels with interply hybrid fiber face sheets (Masoudi Moghaddam et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Damage growth and failure detection in hybrid fiber composites using experimental in-situ optical strain measurements and smoothing element analysis

Tabrizi

Kefal

Zanjani

et al. 2021

International Journal of Damage Mechanics

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In previous study the failure initiation and development in hybrid fiber laminates was successfully monitored and determined. In current investigation a novel damage monitoring approach is proposed for hybrid laminates by combining different optical strain measurement techniques namely digital image correlation (DIC), fiber Bragg grating sensors (FBG) and infrared thermography (IRT) with smoothing element analysis (SEA). This viable experimental procedure eliminates the effects of global/local nature of optical strain measurement systems on heterogeneous damage accumulation and is a two-step approach. First, all optical sensing systems together with conventional strain gauges are utilized concurrently to indicate the differences in the measured strains and monitor damage accumulation under tensile loading. This demonstrates how failure events disturb the measurement capabilities of optical systems, which can cause a miscalculation of hybrid effect in hybrid-fiber laminates. The second step involves the utilization of SEA algorithm for discretely measured DIC displacements to predict a realistic continuous displacement/strain map and rigorously mitigate the inherent noise of the full field optical system. Remarkably, for large deformation states in hybrid composites, the combination of SEA/DIC enables early prediction of susceptible damage zones at stress levels 30% below material strength.

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“…Then, the PD have been widely applied to fracture mechanics simulation of various material and structural systems [36][37][38][39][40]. Further studies such as [41,42] used PD to solve multi-scale structures failure and damage prediction of different materials in composites and layered heterogeneous materials [43]. Recently, Basoglu [44] introduced the PD for integrating micro-crack in structure.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Peridynamics and Finite Element Method for Practical Modeling of Cracks in Topology Optimization

Motlagh

Kefal

2021

Symmetry

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Recently, topology optimization of structures with cracks becomes an important topic for avoiding manufacturing defects at the design stage. This paper presents a comprehensive comparative study of peridynamics-based topology optimization method (PD-TO) and classical finite element topology optimization approach (FEM-TO) for designing lightweight structures with/without cracks. Peridynamics (PD) is a robust and accurate non-local theory that can overcome various difficulties of classical continuum mechanics for dealing with crack modeling and its propagation analysis. To implement the PD-TO in this study, bond-based approach is coupled with optimality criteria method. This methodology is applicable to topology optimization of structures with any symmetric/asymmetric distribution of cracks under general boundary conditions. For comparison, optimality criteria approach is also employed in the FEM-TO process, and then topology optimization of four different structures with/without cracks are investigated. After that, strain energy and displacement results are compared between PD-TO and FEM-TO methods. For design domain without cracks, it is observed that PD and FEM algorithms provide very close optimum topologies with a negligibly small percent difference in the results. After this validation step, each case study is solved by integrating the cracks in the design domain as well. According to the simulation results, PD-TO always provides a lower strain energy than FEM-TO for optimum topology of cracked structures. In addition, the PD-TO methodology ensures a better design of stiffer supports in the areas of cracks as compared to FEM-TO. Furthermore, in the final case study, an intended crack with a symmetrically designed size and location is embedded in the design domain to minimize the strain energy of optimum topology through PD-TO analysis. It is demonstrated that hot-spot strain/stress regions of the pristine structure are the most effective areas to locate the designed cracks for effective redistribution of strain/stress during topology optimization.

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Damage mechanisms in CFRP/HNT laminates under flexural and in-plane shear loadings using experimental and numerical methods

Cited by 17 publications

References 49 publications

Using digital image correlation for in situ strain and damage monitoring in hybrid fiber laminates under in‐plane shear loading

Using digital image correlation for in situ strain and damage monitoring in hybrid fiber laminates under in‐plane shear loading

Damage growth and failure detection in hybrid fiber composites using experimental in-situ optical strain measurements and smoothing element analysis

Comparative Study of Peridynamics and Finite Element Method for Practical Modeling of Cracks in Topology Optimization

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