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Proceedings Paper

Estimation of reliability and dynamic property for polymeric material at high strain rate using SHPB technique and probability theory
Author(s): Dong Hyeok Kim; Ouk Sub Lee; Hong Min Kim; Hye Bin Choi
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Paper Abstract

A modified Split Hopkinson Pressure Bar technique with aluminum pressure bars and a pulse shaper technique to achieve a closer impedance match between the pressure bars and the specimen materials such as hot temperature degraded POM (Poly Oxy Methylene) and PP (Poly Propylene). The more distinguishable experimental signals were obtained to evaluate the more accurate dynamic deformation behavior of materials under a high strain rate loading condition. A pulse shaping technique is introduced to reduce the non-equilibrium on the dynamic material response by modulation of the incident wave during a short period of test. This increases the rise time of the incident pulse in the SHPB experiment. For the dynamic stress strain curve obtained from SHPB experiment, the Johnson-Cook model is applied as a constitutive equation. The applicability of this constitutive equation is verified by using the probabilistic reliability estimation method. Two reliability methodologies such as the FORM and the SORM have been proposed. The limit state function(LSF) includes the Johnson-Cook model and applied stresses. The LSF in this study allows more statistical flexibility on the yield stress than a paper published before. It is found that the failure probability estimated by using the SORM is more reliable than those of the FORM/ It is also noted that the failure probability increases with increase of the applied stress. Moreover, it is also found that the parameters of Johnson-Cook model such as A and n, and the applied stress are found to affect the failure probability more severely than the other random variables according to the sensitivity analysis.

Paper Details

Date Published: 25 August 2009
PDF: 7 pages
Proc. SPIE 7375, ICEM 2008: International Conference on Experimental Mechanics 2008, 73751N (25 August 2009); doi: 10.1117/12.839067
Show Author Affiliations
Dong Hyeok Kim, Inha Univ. (Korea, Republic of)
Ouk Sub Lee, Inha Univ. (Korea, Republic of)
Hong Min Kim, Inha Univ. (Korea, Republic of)
Hye Bin Choi, Inha Univ. (Korea, Republic of)


Published in SPIE Proceedings Vol. 7375:
ICEM 2008: International Conference on Experimental Mechanics 2008

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