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This content will become publicly available on January 25, 2017

Title: Investigation of the dynamic stress–strain response of compressible polymeric foam using a non-parametric analysis

Dynamic stress–strain response of rigid closed-cell polymeric foams is investigated in this work by subjecting high toughness polyurethane foam specimens to direct impact with different projectile velocities and quantifying their deformation response with high speed stereo-photography together with 3D digital image correlation. The measured transient displacement field developed in the specimens during high stain rate loading is used to calculate the transient axial acceleration field throughout the specimen. A simple mathematical formulation based on conservation of mass is also proposed to determine the local change of density in the specimen during deformation. By obtaining the full-field acceleration and density distributions, the inertia stresses at each point in the specimen are determined through a non-parametric analysis and superimposed on the stress magnitudes measured at specimen ends to obtain the full-field stress distribution. Furthermore, the process outlined above overcomes a major challenge in high strain rate experiments with low impedance polymeric foam specimens, i.e. the delayed equilibrium conditions can be quantified.
Authors:
 [1] ;  [1] ;  [2] ;  [1]
  1. Univ. of South Carolina, Columbia, SC (United States)
  2. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Publication Date:
OSTI Identifier:
1237656
Report Number(s):
SAND--2015-4185J
Journal ID: ISSN 0734-743X; PII: S0734743X16300197
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
International Journal of Impact Engineering
Additional Journal Information:
Journal Volume: 91; Journal Issue: C; Journal ID: ISSN 0734-743X
Publisher:
Elsevier
Research Org:
Sandia National Laboratories (SNL-CA), Livermore, CA (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING polymeric foam; direct impact; digital image correlation; non-parametric analysis; parameter identification