A correlation parameter for predicting the compressive strength of composite sandwich panels after low speed impact

Kassapoglou, Christos; Abbott, R. T.

doi:10.2514/6.1988-2294

Cited by 5 publications

(3 citation statements)

References 8 publications

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“…Studies have been conducted to model the impact event in terms of the resulting damage state and to predict the residual strength of the damaged panels. Kassapoglou conducted several studies related to the damage tolerance of composite laminates and thin-gage sandwich panels by modeling the damage as a delamination and a debond [1][2][3][4]. Minguet presented a different approach to modeling the residual strength of damaged sandwich structures in which the damage is modeled as a facesheet indentation with core damage [5].…”

mentioning

confidence: 99%

Scaling and Curvature Effects on the Damage Tolerance of Impacted Composite Sandwich Panels

Moody

Harris

Vizzini

2002

Jnl of Sandwich Structures & Materials

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An experimental program was conducted to investigate the effects of specimen width and specimen curvature on the residual compression strength of composite sandwich panels after low-energy impact. Flat and curved (1.1 m radius) specimens of three widths (83, 152, and 305 mm) were manufactured from thin-gage (four plies) graphite/epoxy facesheets and 25.4-mm-thick Nomex core. A drop mechanism was used to create barely visible impact damage on one facesheet of the panels (convex face of the curved panels) maintaining the energy level as constant in all cases. All specimens were then loaded axially in compression to failure. Above a certain panel width, the panel width and curvature had no effect on the ultimate strength of the panel. Although width and curvature increased the size of the damage caused by an identical energy impact, the indentation growth was delayed with respect to farfield strain (stress). Because indentation growth is chiefly a local phenomenon, the delay was probably due to the variations in the damage state. The baseline specimen (flat, 83 mm in width) serves as an adequate coupon-level test even though it is conservative when compared to wider plates.

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mentioning

confidence: 99%

Scaling and Curvature Effects on the Damage Tolerance of Impacted Composite Sandwich Panels

Moody

Harris

Vizzini

2002

Jnl of Sandwich Structures & Materials

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“…These results suggest that the backside facesheet may play an important role in the failure process (i.e., local hemispherical crippling of the sandwich panel may be a real concern). Note that sandwich composite models that simulate the core material using an elastic or inelastic foundation idealization [37][38][39][40] cannot possibly capture this effect. See [29] for a comparison of the measured and estimated strains at the remaining strain gauge locations as well as for validation data involving additional sandwich panels.…”

Section: Finite Element Model Validationmentioning

confidence: 99%

Numerical Estimates of the Compressive Strength of Impact-damaged Sandwich Composites

Hwang

Lacy

2007

Journal of Composite Materials

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Improved numerical models have been developed for predicting the compressive strength of impact-damaged sandwich composites comprised of woven-fabric graphite-epoxy facesheets and Nomex honeycomb cores. The proposed methodology contains three key elements: (1) the use of nondestructive inspection estimates of damage, (2) the incorporation of nonlinear through-the-thickness core-crush constitutive response to account for core failure, and importantly (3) the simulation of progressive loss of facesheet structural integrity based upon userspecified ply failure criteria. The finite element predictions of residual strength for panels impacted with relatively blunt objects correlate well with the experimental observations; this is in contrast to a number of estimates from literature that tend to overestimate the strength. The proposed approach may potentially facilitate sandwich design by providing insight into the relationships between material configuration and damage that lead to improved damage tolerance characteristics.

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“…Kassapoglou et al [ 17 ] developed an analytical model to predict compressive buckling of sandwich panels with elliptical cracks (delamination) in the area of the interface composite/core. Kassapoglou and Abbott used a simple buckling eigenvalue [ 18 ] to calculate the critical buckling load a local elliptical damage. Shipsha et al [ 19 ] studied the effect of low velocity impact damage on residual compression and bending strength of sandwich plates.…”

Section: Introductionmentioning

confidence: 99%

Face Damage Growth of Sandwich Composites under Compressive Loading: Experiments, Analytical and Finite Element Modeling

et al. 2021

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Sandwich panels with composite laminate skins having [(±45C)2,(0C,0G)4,(±45C)2] stacking sequence (subscript C for carbon fibers, G for glass) and containing barely visible impact damage (BVID) induced on the whole sandwich structure impacted at low energy, were tested in edge after-impact-compression with load direction parallel and transversal to the fibers direction (0-dir.). The morphology of impact damage on the sandwich structure was determined by using ultrasonic C-Scan and visual observation of laminate cross section. A Digital Image Correlation (DIC) system was used to measure the delamination evolution during the test. Two different failure behaviors were observed in two different impacted panels. Panel with fibers oriented transversally to the compressive load showed an opening (Mode-I) propagation of a delamination, while the panel with fibers parallel to the load showed shear (Mode-II) propagation. The static load such to determine local buckling of the composite face and failure was experimentally measured. An analytical model was implemented to predict the static strength of laminate with Mode-I opening. An FE model was instead built to predict the local buckling failure mode of the laminate with BVID, which is the first phenomenon to appear. The results of the analytical model and the numerical simulation correlate well with the test.

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A correlation parameter for predicting the compressive strength of composite sandwich panels after low speed impact

Cited by 5 publications

References 8 publications

Scaling and Curvature Effects on the Damage Tolerance of Impacted Composite Sandwich Panels

Scaling and Curvature Effects on the Damage Tolerance of Impacted Composite Sandwich Panels

Numerical Estimates of the Compressive Strength of Impact-damaged Sandwich Composites

Face Damage Growth of Sandwich Composites under Compressive Loading: Experiments, Analytical and Finite Element Modeling

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