High strain rate characterization of off-axis composites using Split Hopkinson Pressure Bar

Ninan, Lal; Sun, C.T.

doi:10.2514/6.1999-1368

Cited by 4 publications

(5 citation statements)

References 9 publications

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“…They have observed that the stress/strain curves showed little difference at different orientations, but, when compared with quasi-static stress/strain curve, the effect of strain rate was evident. Ninan et al attempted to characterize the high strain rate behavior of fiber composites using off-axis composite specimens and SHPB 8,9 . Various factors affecting the SHPB analysis, such as specimenbar interface friction and extension shear coupling were numerically and experimentally investigated.…”

Section: Introductionmentioning

confidence: 99%

High Strain Rate Compression Characterization of Affordable Woven Carbon/Epoxy Composites under Off-Axis Loading

Hosur

Alexander

Vaidya

et al. 2003

Polymers and Polymer Composites

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This paper discusses an experimental study on the response of affordable plain weave carbon/epoxy composite laminates to high strain rate compression loading using a modified Compression Split Hopkinson's Pressure Bar (SHPB) under off-axis loading. 37 layer laminates were manufactured using aerospace grade woven fabrics with a SC-15 epoxy resin system, utilizing a Vacuum Assisted Resin Infusion Molding (VARIM) approach. Samples were subjected to high strain rate compression loading at strain rates ranging from 1187/s to 2289/s in the plane of the laminates, using a modified SHPB that facilitates controlled single pulse loading of the sample. Samples were tested along 0°,15°, 30°, and 45° off-axes angles. Quasi-static tests were carried out to compare them with the dynamic response. Failure modes were evaluated using optical micrographs. Results were analyzed in terms of peak stress, strain at peak stress, failure modes and orientation.

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Section: Introductionmentioning

confidence: 99%

High Strain Rate Compression Characterization of Affordable Woven Carbon/Epoxy Composites under Off-Axis Loading

Hosur

Alexander

Vaidya

et al. 2003

Polymers and Polymer Composites

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“…Thus, the average sample stress is the mean of the stresses at the interfaces, i.e., ). (27) Assuming uniform stress through a thin specimen, ε t (t) = ε i (t) + ε r (t) and σ t (t)= σ i (t) + σ r (t), (28) and Equations (20) and (21) give the strain and strain rate as ), Equation 28 shows that stress is proportional to strain. The elastic Young's modulus, E 0 , is applied when the magnitude of the stress is less than the yield stress of the material.…”

Section: Stress Particle Velocity and Force Measurementsmentioning

confidence: 99%

“…At higher strain rates, they report decrease in both strength and stiffness. Weeks et al [12] and Ninan et al [13] have reported that the stress-strain relation is linear only when the sample is loaded in the longitudinal direction. Shankar et al [14] have investigated the dynamic compressive properties of a uniweave composite laminate with and without reinforcement stitching and have reported that there is a reduction in peak stress value due to stitching.…”

Section: Introductionmentioning

confidence: 99%

“…Weeks et al observed that the stress/strain curves showed little difference at different orientations, but when compared with quasi-static stress/strain curve, the effect of strain rate was evident. Ninan et al [28,29] attempted to characterize the high strain rate behavior of fiber composites using off-axis composite specimens and SHPB. Various factors affecting the SHPB analysis, such as specimen-bar interface friction and extension shear coupling, were numerically and experimentally investigated.…”

Section: Introductionmentioning

confidence: 99%

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Survivability of Affordable Aircraft Composite Structures. Volume 2: High Strain Rate Characterization of Affordable Woven Carbon/Epoxy Composites

Hosur¹,

Jeelani²,

Vaidya³

et al. 2003

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“…At higher strain rates, they reported a decrease in both strength and stiffness. Weeks et al 12 and Ninan et al 13 have reported that the stress-strain relation is linear only when the sample is loaded in the longitudinal direction. Shankar et al investigated the dynamic compressive properties of a uniweave composite laminate with and without reinforcement stitching and have reported that there was a reduction in peak stress value due to stitching 14 .…”

Section: Introductionmentioning

confidence: 99%

On the Response of Stitched Woven S2-Glass/Epoxy Composites to High Strain Rate Compression Loading

Hosur

Karim

Jeelani

2004

Polymers and Polymer Composites

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Experimental investigations were carried out to understand the response of stitched/unstitched S2-Glass/SC-15 epoxy composites to high strain rate compression loading using a Split Hopkinson Pressure Bar set-up. Fifteen layers of plain weave S2-glass fabric were used to fabricate stitched/unstitched laminates with a low viscosity room temperature curing SC-15 epoxy resin system. For stitching, a 3-cord Kevlar thread was used. The fabric preforms were stitched through the thickness in a lock-stitch pattern, maintaining a pitch of 6 mm. The fabric was stitched along the length and width, forming a 25.4 mm stitch grid. Four different types of samples were considered. Sample configuration was designated according to the location of the stitch line with reference to the loading direction. Dynamic and static responses of the laminate under compression were compared. Failure modes were studied using optical microscopy. For high strain rate loading, samples of dimension 22.5 × 22.5 × 9.5 mm were tested at five different pressure settings of the Hopkinson Bar Set-up. Results were analysed in terms of peak stress, strain at peak stress, modulus and failure modes. Results of the study showed that, under higher strain rates loading, the stitched laminates exhibited a confining effect. The primary mode of failure for unstitched samples was fibre microbuckling with multiple delaminations. For stitched samples, fibre microbuckling and micro-delaminations were the major modes of failure and were contained within the bounds of the stitch. Overall, stitched laminates will provide increased damage resistance, which will prove very crucial under crash situations.

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High strain rate characterization of off-axis composites using Split Hopkinson Pressure Bar

Cited by 4 publications

References 9 publications

High Strain Rate Compression Characterization of Affordable Woven Carbon/Epoxy Composites under Off-Axis Loading

High Strain Rate Compression Characterization of Affordable Woven Carbon/Epoxy Composites under Off-Axis Loading

Survivability of Affordable Aircraft Composite Structures. Volume 2: High Strain Rate Characterization of Affordable Woven Carbon/Epoxy Composites

On the Response of Stitched Woven S2-Glass/Epoxy Composites to High Strain Rate Compression Loading

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