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Title: Constitutive models for rubber networks undergoing simultaneous crosslinking and scission.

Abstract

Constitutive models for chemically reacting networks are formulated based on a generalization of the independent network hypothesis. These models account for the coupling between chemical reaction and strain histories, and have been tested by comparison with microscopic molecular dynamics simulations. An essential feature of these models is the introduction of stress transfer functions that describe the interdependence between crosslinks formed and broken at various strains. Efforts are underway to implement these constitutive models into the finite element code Adagio. Preliminary results are shown that illustrate the effects of changing crosslinking and scission rates and history.

Authors:
; ;  [1]; ; ;
  1. (University of New Mexico, Albuquerque, NM)
Publication Date:
Research Org.:
Sandia National Laboratories
Sponsoring Org.:
USDOE
OSTI Identifier:
877144
Report Number(s):
SAND2005-7357
TRN: US200606%%715
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; CHEMICAL REACTIONS; RUBBERS; STRAINS; MATHEMATICAL MODELS; MOLECULAR DYNAMICS METHOD; CROSS-LINKING; FINITE ELEMENT METHOD; Molecular dynamics.; Matter-Constitution-Mathematical models.

Citation Formats

Thompson, Aidan Patrick, Curro, John G., Rottach, Dana R., Grest, Gary Stephen, Budzien, Joanne L., and Lo, David Chi S. Constitutive models for rubber networks undergoing simultaneous crosslinking and scission.. United States: N. p., 2006. Web. doi:10.2172/877144.
Thompson, Aidan Patrick, Curro, John G., Rottach, Dana R., Grest, Gary Stephen, Budzien, Joanne L., & Lo, David Chi S. Constitutive models for rubber networks undergoing simultaneous crosslinking and scission.. United States. doi:10.2172/877144.
Thompson, Aidan Patrick, Curro, John G., Rottach, Dana R., Grest, Gary Stephen, Budzien, Joanne L., and Lo, David Chi S. Sun . "Constitutive models for rubber networks undergoing simultaneous crosslinking and scission.". United States. doi:10.2172/877144. https://www.osti.gov/servlets/purl/877144.
@article{osti_877144,
title = {Constitutive models for rubber networks undergoing simultaneous crosslinking and scission.},
author = {Thompson, Aidan Patrick and Curro, John G. and Rottach, Dana R. and Grest, Gary Stephen and Budzien, Joanne L. and Lo, David Chi S.},
abstractNote = {Constitutive models for chemically reacting networks are formulated based on a generalization of the independent network hypothesis. These models account for the coupling between chemical reaction and strain histories, and have been tested by comparison with microscopic molecular dynamics simulations. An essential feature of these models is the introduction of stress transfer functions that describe the interdependence between crosslinks formed and broken at various strains. Efforts are underway to implement these constitutive models into the finite element code Adagio. Preliminary results are shown that illustrate the effects of changing crosslinking and scission rates and history.},
doi = {10.2172/877144},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}

Technical Report:

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  • Abstract not provided.
  • A compressed natural rubber vulcanizate was exposed to 10/sup 8/ r of gamma radiation and allowed to reach its set length it 40 C after release from compression. Compression set, crosslinking and scission of the elastomer network varied with degree of cure. (auth)
  • Physically based models which describe the finite strain behavior of vulcanized rubber are developed. Constitutive laws for elasticity and viscoelasticity are derived by integrating over orientation space the forces due to each individual polymer chain. A novel scheme is presented which effectively approximates these integrals in terms of strain and strain invariants. In addition, the details involving the implementation of such models into a quasi-static large strain finite element formulation are provided. In order to account for the finite extensibility of a molecular chain, Langevin statistics is used to model the chain response. The classical statistical model of rubber assumesmore » that polymer chains interact only at the chemical crosslinks. It is shown that such model when fitted for uniaxial tension data cannot fit compression or equibiaxial data. A model which incorporates the entanglement interactions of surrounding chains, in addition to the finite extensibility of the chains, is shown to give better predictions than the classical model. The technique used for approximating the orientation space integral was applied to both the classical and entanglement models. A viscoelasticity model based on the force equilibration process as described by Doi and Edwards is developed. An assumed form for the transient force in the chain is postulated. The resulting stress tensor is composed of an elastic and a viscoelastic portion with the elastic stress given by the proposed entanglement model. In order to improve the simulation of experimental data, it was found necessary to include the effect of unattached or dangling polymer chains in the viscoelasticity model. The viscoelastic effect of such chains is the manifestation of a disengagement process. This disengagement model for unattached polymer chains motivated an empirical model which was very successful in simulating the experimental results considered.« less