Accession Number:

AD0880429

Title:

Failure Criteria for Polymeric Solids

Personal Author(s):

Corporate Author:

MONSANTO RESEARCH CORP ST LOUIS MO

Report Date:

1971-01-01

Abstract:

A theory for predicting the stress-strain characteristics of polymeric solids developed in terms of a description of microdefect formation. The process of irreversible change in these solids is assumed to be a combination of nucleation of submicroscopic defects at stress inhomogeneities and their subsequent growth to macroscopic dimensions. Straining results in the simultaneous generation of free volume and macrodefects so that catastrophic failure can occur through either a general yielding of the material or by brittle fracture. It is assumed that nucleation of sub-microscopic defects is an activated process and that defect growth is one dimensional and linear. The total strain is expressed as the sum of an elastic recoverable strain and a nonlinear, nonrecoverable strain and expressions are obtained for the stress as a function of time, temperature and loading history. The criterion for yielding is defined in terms of free volume concepts and a criterion for brittle failure is defined in terms of a critical defect size. The parameters of the resulting model are calculated for polyphenylene oxide polymers based on constant rate of loading experiments and then the general creep behavior,including the time required under constant load for cold flow, is predicted. Experimental data are shown to agree with these predictions.

Supplementary Note:

Report on Monsanto/Washington Univ., ONR/ARPA Association project development of High Performance Composites. Continuation of Contract N00014-66-C-0045.

Pages:

0033

Descriptors:

Identifiers:

Subject Categories:

Communities Of Interest:

Distribution Statement:

Approved for public release; distribution is unlimited.

Contract Number:

N00014-67-C-0218

Contract Number 2:

ARPA ORDER-876

File Size:

1.95MB

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