Transverse cracks in cross-ply laminates. 1. Stress analysis

Krasņikovs, Andrejs; Vārna, Jānis

doi:10.1007/bf02269616

Cited by 17 publications

(8 citation statements)

References 17 publications

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“…Validation of an analytical micromechanics model consists of two parts: (a) the adequacy of the physical model to real crack (including crack geometry); (b) the numerical accuracy of the mathematical solution applied for this model. The latter can be verified comparing the obtained stress distributions with stress state obtained using FEM, see Krasnikovs and Varna 15 for example. The adequacy of a model with accurate mathematical solution can be validated on the macroscopic scale by comparing the measured values of the elastic constants of a damaged laminate and the predicted values for example as in Hashin, 13 Varna and Berglund, 14 and Joffe et al 16 In Laws and Dvorak 17 the measured stiffness reduction was used to backcalculate the shear lag parameter.…”

Section: Introductionsupporting

confidence: 58%

“…With the assumption of an elliptical opening, the value on the midplane, COD Hashin 0 ð Þ is given by Equation (15). For Crack_b, Crack_c, Crack_d, the values for COD Hashin 0 ð Þ are shown in Table 4.…”

Section: Hashin's Modelmentioning

confidence: 99%

“…The COD 0 ð Þ values are indicated on Figure 5 for the four cracks. With Equations ( 13), (15), and (17) it is easy to obtain an implicit equation for :…”

Section: Shear Lag Parameter Determination From Cod Measurementsmentioning

confidence: 99%

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Use of full-field measurements to evaluate analytical models for laminates with intralaminar cracks

Farge

Vārna

Ayadi

2012

Journal of Composite Materials

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Full-field displacement measurements between intralaminar cracks in cross-ply laminates were performed to evaluate the accuracy of shear lag models and Hashin's model. The dependence of the average crack opening displacement on the crack density was measured and compared with model predictions. It was found that Hashin's model overestimates the average COD by at least 25%. The value of the shear lag parameter was back-calculated by fitting. With the same goal the strain in the middle between two cracks was measured rendering shear lag parameter which was only 1% different. The found value does not agree with any of the used shear lag models. Measurement shows nonzero intralaminar shear zones in both layers covering a part of the ply thickness.

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Section: Introductionsupporting

confidence: 58%

Section: Hashin's Modelmentioning

confidence: 99%

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Use of full-field measurements to evaluate analytical models for laminates with intralaminar cracks

Farge

Vārna

Ayadi

2012

Journal of Composite Materials

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“…Defects of this kind, undoubtedly, have an adverse effect on the laminate mechanical properties; they can constitute an area of crack initiation. 7,44,45 However, the ''chambers' are distributed uniformly on the whole surface of the board, and so they do not locally disturb the material's properties or the global scatter of results (their negative effect is uniform for the whole panel surface). The cross-section of the structure of the fabric laminate produced by VARI demonstrates a good adhesion of the layers, without any visible undersaturated areas (Figure 10(a)).…”

Section: Analysis Of the Resultsmentioning

confidence: 99%

Repeatability of glass fiber reinforced polymer laminate panels manufactured by hand lay-up and vacuum-assisted resin infusion

Rydarowski

Kozioł

2014

Journal of Composite Materials

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The paper presents a comparison of the test results for the fiber volume fraction, static bending and Charpy impact strength of glass fiber reinforced polymer laminates reinforced by 0/90 fabric and chopped strand mat, produced by the hand lay-up and the vacuum-assisted resin infusion (VARI) method. The laminates were produced under equivalent conditions, with polyester matrix and lay-up areal mass 2100 g/m2. In the comparison of the obtained measurement results, similar mechanical performance was stated in the case of the hand lay-up and the VARI production. However, significantly smaller scatter of results and better uniformity of the reinforcement in the matrix with smaller amount of local structure defects was observed for the samples obtained by VARI method. The laminates obtained by VARI method show a much more advantageous coefficient of variation than that of the hand lay-up method, especially in the case of the mat reinforcement.

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“…Such models hence fail to capture the hybrid effect, as described in Section 3.1 . Theoretically however, it is well recognised that cracks in off-axis plies locally increase the stresses in the 0° plies [ 76 ]. That should hence increase the probability for fibre break development and reduce the in situ strength of the 0° plies.…”

Section: Tensile Failurementioning

confidence: 99%

Perspective for Fibre-Hybrid Composites in Wind Energy Applications

Swolfs

2017

Materials

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Increasing the efficiency of wind turbines will be vital for the wind energy sector to continue growing. The drive for increased efficiency is pushing turbine manufacturers to shift from glass fibre composite blades towards carbon/glass fibre-hybrid composite blades. This shift brings significant challenges in terms of optimising the design and understanding the failure of these new blade materials. This review therefore surveys the literature on fibre-hybrid composites, with an emphasis on aspects that are relevant for turbine blade materials. The literature on tensile, flexural, compressive, and fatigue performance is critically assessed and areas for future research are identified. Numerical simulations of fibre-hybrid composites have reached a reasonable maturity for tensile failure, but significant progress is required for flexural, compressive, and fatigue failure. Fatigue failure of fibre-hybrid composites in particular, requires more careful attention from both a modelling and experimental point of view.

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Transverse cracks in cross-ply laminates. 1. Stress analysis

Cited by 17 publications

References 17 publications

Use of full-field measurements to evaluate analytical models for laminates with intralaminar cracks

Use of full-field measurements to evaluate analytical models for laminates with intralaminar cracks

Repeatability of glass fiber reinforced polymer laminate panels manufactured by hand lay-up and vacuum-assisted resin infusion

Perspective for Fibre-Hybrid Composites in Wind Energy Applications

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