Effect of stitching on impact and interlaminar properties of graphite/epoxy laminates

Sharma, S K; Sankar, B V

Title: Effect of stitching on impact and interlaminar properties of graphite/epoxy laminates

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Abstract

Effects of through-the-thickness stitching on the impact damage resistance, impact damage tolerance and interlaminar fracture toughness (Mode I and Mode II) of plain woven and uniweave textile graphite/epoxy laminates are investigated. The laminates were manufactured using resin-infusion-molding and resin-transfer-molding processes. Kevlar{reg_sign} and glass yarns of different yam numbers were used for stitching. Static Indentation-flexure (SI), Compression-After-Impact (CAI), Double-Cantilever-Beam (DCB) and End-Notched-Flexure (ENF) tests were conducted. Stitching did not have any significant effect on impact damage resistance. However, stitching leads to significant improvement (25-40%) in impact damage tolerance as measured by CAI strength and impact damage area. Mode I fracture toughness as characterized by critical strain energy release rate (G{sub Ic}) was found to increase by at least an order higher (15--30 times) than the unstitched laminates. Mode II fracture toughness (G{sub Ic}) increased by 5--15 times over the unstitched laminates. New methods to estimate Mode 11 critical strain energy release rate in the stitched laminates are presented.

Authors:

Sharma, S K; Sankar, B V ^[1]

Univ. of Florida, Gainesville, FL (United States). Dept. of Aerospace Engineering, Mechanics, and Engineering Science

Publication Date:: Sat Dec 31 00:00:00 EST 1994

OSTI Identifier:: 89849

Report Number(s):: CONF-9409291-
ISBN 1-56676-220-0; TRN: IM9536%%279

Resource Type:: Conference

Resource Relation:: Conference: 9. technical conference of the American Society for Composites, Newark, DE (United States), 20-22 Sep 1994; Other Information: PBD: 1994; Related Information: Is Part Of Proceedings of the American Society for Composites: Ninth technical conference; PB: 1319 p.

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; COMPOSITE MATERIALS; IMPACT STRENGTH; FRACTURE PROPERTIES; CARBON FIBERS; EPOXIDES; ARAMIDS; FIBERGLASS; SAMPLE PREPARATION; CRACK PROPAGATION; PHOTOMICROGRAPHY; X-RAY RADIOGRAPHY; ULTRASONIC TESTING; SCANNING ELECTRON MICROSCOPY

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                    Sharma, S K, and Sankar, B V. Effect of stitching on impact and interlaminar properties of graphite/epoxy laminates.  United States: N. p., 1994. 
        Web.

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                    Sharma, S K, & Sankar, B V. Effect of stitching on impact and interlaminar properties of graphite/epoxy laminates.  United States.

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                    Sharma, S K, and Sankar, B V. 1994.  
        "Effect of stitching on impact and interlaminar properties of graphite/epoxy laminates".  United States.

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@article{osti_89849,

  title        = {Effect of stitching on impact and interlaminar properties of graphite/epoxy laminates},

  author       = {Sharma, S K and Sankar, B V},

  abstractNote = {Effects of through-the-thickness stitching on the impact damage resistance, impact damage tolerance and interlaminar fracture toughness (Mode I and Mode II) of plain woven and uniweave textile graphite/epoxy laminates are investigated. The laminates were manufactured using resin-infusion-molding and resin-transfer-molding processes. Kevlar{reg_sign} and glass yarns of different yam numbers were used for stitching. Static Indentation-flexure (SI), Compression-After-Impact (CAI), Double-Cantilever-Beam (DCB) and End-Notched-Flexure (ENF) tests were conducted. Stitching did not have any significant effect on impact damage resistance. However, stitching leads to significant improvement (25-40%) in impact damage tolerance as measured by CAI strength and impact damage area. Mode I fracture toughness as characterized by critical strain energy release rate (G{sub Ic}) was found to increase by at least an order higher (15--30 times) than the unstitched laminates. Mode II fracture toughness (G{sub Ic}) increased by 5--15 times over the unstitched laminates. New methods to estimate Mode 11 critical strain energy release rate in the stitched laminates are presented.},

  doi          = {},

  url          = {https://www.osti.gov/biblio/89849},
  journal      = {},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {Sat Dec 31 00:00:00 EST 1994},

  month        = {Sat Dec 31 00:00:00 EST 1994}

}

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