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IMPACT PERFORMANCE AND BENDING BEHAVIOR OF COMPOSITE SANDWICH STRUCTURES IN COLD TEMPERATURE ARCTIC CONDITION

Khan, Md Mahfujul H
http://orcid.org/0000-0002-7803-0205
http://rave.ohiolink.edu/etdc/view?acc_num=akron1580471034677078

Abstract Details

2020, Doctor of Philosophy, University of Akron, Mechanical Engineering.
This study investigates experimental impact performance, underlying damage mechanisms and post-impact flexural strength of Carbon fiber-reinforced polymer face sheets with PVC foam core sandwich panel in cold temperature Arctic conditions. Analytical and statistical predictions on post-impact bending behaviour is further validated with the experimental results. A series of low-velocity impact tests were performed using an instrumented falling weight test system at room and low temperatures. Exposure to low temperature degrades the damage tolerance of the CFRP face sheet at higher loads significantly. Post-mortem inspection using X-ray micro-computed tomography elucidates complex failure mechanisms in the CFRP composite face sheets (matrix crack, delamination, and fiber breakage) and foam core (core crushing, core shearing and interfacial debonding). Post-impact flexural behavior is analyzed for CFRP-PVC sandwich panels. Bending test results elucidated that properties are more sensitive to the inplane compressive property of the CFRP face sheet than in-plane tensile property. Specifically, the degradation of flexural strength strongly depends on existing prebend damage due to impact loading. Statistical analyses are employed to demonstrate that flexural performance is mainly governed by face sheet thickness and pre-bend impact energy. Analytical predictions on flexural collapse modes for CFRP-PVC reveal indentation, core shear and face wrinkling as the main competing failure modes, whereby the dominant mechanism is dependent on preexisting impact damage, face sheet thickness, environmental temperature, and bending configuration. Results portray that thick face sheet specimens collapse mainly by indentation or core shear. However, thin face sheet specimens display novel collapse mechanisms such as core tensile failure and debonding. Core tensile failure is attributed to the degraded tensile strength of back face sheet at extreme low temperatures. The final part of this work further explores a comparative analysis on the impact behavior and underlying damage mechanics between Carbon fiber reinforced polymer (CFRP), Glass fiber reinforced polymer (GFRP) and Carbon- Glass fiber hybrid face sheet to PVC foam core sandwich panel. Forcedisplacement and energy absorbed (%) results revealed that fiber hybridization leads to better impact resistance compared to CFRP-PVC, particularly at low temperatures. The extent of core damage namely core crushing and core shearing is also reduced when carbon fibers are hybridized with glass fibers. Impacted face sheet damage mechanism switches from severe fiber breakage (CFRP-PVC) to extensive delamination (Hybrid-PVC). Moreover, distal back face sheet splitting (CFRP-PVC) is hindered for the Carbon-Glass fiber hybrid face sheet sandwich panel.
Kwek-Tze Tan, PhD (Advisor)
Shing-Chung Wong, PhD (Committee Member)
Gregory Morscher, PhD (Committee Member)
Ping Yi, PhD (Committee Member)
J. Patrick Wilber, PhD (Committee Member)
102 p.
Mechanical Engineering
Low-temperature impact, Flexural collapse modes, Damage mechanisms, Fiber hybrid sandwich, Arctic condition

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Citations

  • Khan, M. M. H. (2020). IMPACT PERFORMANCE AND BENDING BEHAVIOR OF COMPOSITE SANDWICH STRUCTURES IN COLD TEMPERATURE ARCTIC CONDITION [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1580471034677078

    APA Style (7th edition)

  • Khan, Md Mahfujul. IMPACT PERFORMANCE AND BENDING BEHAVIOR OF COMPOSITE SANDWICH STRUCTURES IN COLD TEMPERATURE ARCTIC CONDITION. 2020. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1580471034677078.

    MLA Style (8th edition)

  • Khan, Md Mahfujul. "IMPACT PERFORMANCE AND BENDING BEHAVIOR OF COMPOSITE SANDWICH STRUCTURES IN COLD TEMPERATURE ARCTIC CONDITION." Doctoral dissertation, University of Akron, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1580471034677078

    Chicago Manual of Style (17th edition)

akron1580471034677078
© 2020, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.