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In situ deformation characterization of density-graded foams in quasi-static and impact loading conditions

Koohbor, Behrad and Ravindran, Suraj and Kidane, Addis (2021) In situ deformation characterization of density-graded foams in quasi-static and impact loading conditions. International Journal of Impact Engineering, 150 . Art. No. 103820. ISSN 0734-743X. https://resolver.caltech.edu/CaltechAUTHORS:20210115-132721219

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Abstract

Digital image correlation is utilized to characterize deformation and strain fields developed within the layers of density-graded multilayered foam structures subjected to uniaxial quasi-static and dynamic compression. Three-layered graded structures fabricated from rigid polyurethane foams with nominal densities of 160, 240, and 320 kg/m³ are subjected to quasi-static and dynamic loading. The quasi-static measurements show that, irrespective of the loading direction, the densification is initiated in the lowest density layer and propagates into other layers later once the first layer is fully densified. The deformation mechanisms are different in the case of dynamic loading conditions than quasi-static loading. In the case of dynamic loading, the deformation mechanism depends on the sample orientation relative to the direction of the applied load. In cases where the higher density layers are impacted, the propagation of the elastic and compaction waves leads to partial deformation of the lowest density layer. Sample deformation continues in all layers upon the reflection of the stress waves from the distal end of the sample. A completely different deformation response is observed in cases where the lowest density layer is oriented towards the impact face. A detailed full-field analysis of strain and stress is performed. The mechanisms associated with the formation and propagation of stress waves from the impact end to the samples' distal end are discussed.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.ijimpeng.2021.103820DOIArticle
ORCID:
AuthorORCID
Koohbor, Behrad0000-0002-5787-4644
Ravindran, Suraj0000-0003-2930-7906
Additional Information:© 2021 Elsevier. Received 25 August 2020, Revised 3 November 2020, Accepted 11 January 2021, Available online 13 January 2021. The authors wish to acknowledge Dr. Michael A. Sutton at the University of South Carolina for insightful discussions. The financial support of Army Research Office (ARO)/DOD under Grant no. W911NF-18-1-0023 is gratefully acknowledged. Data availability: Data will be made available upon request. CRediT author statement: Behrad Koohbor: Conceptualization, Methodology, Writing-Original draft preparation. Suraj Ravindran: Methodology, Experiments, Writing-Reviewing and Editing. Addis Kidane: Conceptualization, Writing-Reviewing and Editing, Supervision, Funding Acquisition. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Group:GALCIT
Funders:
Funding AgencyGrant Number
Army Research Office (ARO)W911NF-18-1-0023
Subject Keywords:Density graded; foam; impact; digital image correlation; inertia
Record Number:CaltechAUTHORS:20210115-132721219
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210115-132721219
Official Citation:Behrad Koohbor, Suraj Ravindran, Addis Kidane, In situ deformation characterization of density-graded foams in quasi-static and impact loading conditions, International Journal of Impact Engineering, Volume 150, 2021, 103820, ISSN 0734-743X, https://doi.org/10.1016/j.ijimpeng.2021.103820. (http://www.sciencedirect.com/science/article/pii/S0734743X21000075)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107514
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:15 Jan 2021 22:51
Last Modified:28 Jan 2021 22:28

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