The influence of lay-up and thickness on composite impact damage andcompression strength

Guynn, E. Gail; O’Brien, TK

doi:10.2514/6.1985-646

Cited by 38 publications

(25 citation statements)

References 1 publication

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“…The area of the impact-induced delamination within the sublaminate is assumed to be circular in shape. While the actual measured shape of the delamination zone is typically more complex [13], the assumption of circular delamination zone has been employed in prior investigations [17,27] and adopted in this study. The largest delamination under impact loading is observed between the 7th and 8th plies.…”

Section: Numerical Modeling Of Cai Failurementioning

confidence: 99%

Compression-after-impact response of woven fiber-reinforced composites

Yan

Oskay

Krishnan

et al. 2010

Composites Science and Technology

109

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Section: Numerical Modeling Of Cai Failurementioning

confidence: 99%

Compression-after-impact response of woven fiber-reinforced composites

Yan

Oskay

Krishnan

et al. 2010

Composites Science and Technology

109

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“…In a recent study, Guynn and O'Brien [3], used a de-ply technique to show that delaminations of impacted regions are always associated with matrix cracking. They observed that matrix cracks will form first through the laminate plies and parallel to the fiber direction.…”

mentioning

confidence: 99%

Analysis of Delamination Growth from Matrix Cracks in Laminates Subjected to Bending Loads

Murri

Guynn

1988

Composite Materials: Testing and Design (Eighth Conference)

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Delamination is the most commonly observed damage mode in laminated composite materials. A major source of delamination damage is from low-velocity impact. In thin composite laminates under point loads, matrix cracks develop first in the plies, and delaminations then grow from these cracks at the ply interfaces. The purpose of this study was to quantify the combined effects of bending and transverse shear loads on delamination initiation from matrix cracks in composite laminates. Graphite-epoxy laminates with 90-deg plies on the outside were tested and analyzed to provide a two-dimensional simulation of the back-surface damage observed during low-velocity impact. Three plate-bending problems were considered: four-point bending, three-point bending, and an end-clamped center-loaded plate. Under bending, a matrix crack will form on the tension side of the laminate, through the outer 90-deg plies and parallel to the fibers. Delaminations will then grow in the interface between the cracked 90-deg ply and the next adjacent ply. Laminate plate theory was used to derive simple equations relating the total strain energy release rate G, associated with the delamination growth from a 90-deg ply crack, to the applied bending load and laminate stiffness properties. Three different lay-ups, [904/0/±45]s, [904/03]s, and [903/0/±45]s, were tested and results compared. Test results verified that in all cases the delamination formed at the interface between the cracked 90-deg ply and the next adjacent ply. Calculated values for total Gc from the analysis showed good agreement for the three lay-ups and the three different test configurations. Using an assumed value for GIc from a previous study, the analysis was able to predict the delamination onset load for the cases considered. The result indicates that the opening mode component (Mode I) for delamination growth may be much larger than the component due to interlaminar shear (Mode II) from a matrix crack.

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“…It was observed from the previous experiments that impact damage can be significantly affected by the laminate configuration, including ply orientation and thickness, and the energy of the impactor. Similar phenomena have also been recorded in the literature for the impact damage resulting from traditional point-nose impactors [4][5][6][7][8][9][10]. Apparently, there exist relationships that can relate the impact damage to the material properties, geometry, ply orientation, and mass and velocity of the impactor.…”

Section: Introduction R Ecentlymentioning

confidence: 61%

Effect of Laminate Configuration and Impactor's Mass on the Initial Impact Damage of Graphite/Epoxy Composite Plates Due to Line-Loading Impact

Choi

Wang

Chang

1992

Journal of Composite Materials

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An investigation was performed to study the effect of stacking sequence, thickness, and impactor's mass on the impact damage of graphite/epoxy laminated composites due to low-velocity impact. The major focus of the study was concentrated on the initial damage and the corresponding impact energy with respect to these parameters. Experiments were performed using specially designed line-nose impactors by which the resulting impact damage and failure mode of the composites could easily be inspected. Accordingly, the velocities of the impactors causing initial impact damage in the composites were determined, and the effects of the laminate configuration and the mass of the impactor on the damage were established. Numerical simulations based on the model, which was developed previously, were also performed in order to understand the basic mechanics and mechanisms governing the phenomena observed from the experiments. Based on the study, it can be concluded that the change of stacking sequence significantly influences the impact damage much more than the change of thickness. Initial impact damage is also very sensitive to the mass of the impactor, and both velocity and mass of the impactor have to be specified in order to adequately characterize impact damage in composites.

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The influence of lay-up and thickness on composite impact damage andcompression strength

Cited by 38 publications

References 1 publication

Compression-after-impact response of woven fiber-reinforced composites

Compression-after-impact response of woven fiber-reinforced composites

Analysis of Delamination Growth from Matrix Cracks in Laminates Subjected to Bending Loads

Effect of Laminate Configuration and Impactor's Mass on the Initial Impact Damage of Graphite/Epoxy Composite Plates Due to Line-Loading Impact

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