An improved unified viscoplastic polymer constitutive formulation for multiscale analysis of polymer matrix composites under high strain rate loading

Christopher Sorini, Aditi Chattopadhyay, Robert K. Goldberg

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Carbon fiber reinforced polymer matrix composites are commonly used to fabricate energy-absorbing structures expected to experience impact loading. As such, a detailed understanding of the response of the constituent materials is necessary. Since the rate, temperature, and pressure dependence of fiber reinforced polymer matrix composites is a manifestation of the rate, temperature, and pressure dependence of the polymer matrix, it is crucial that the constitutive behavior of the polymer be accurately characterized. In this work, an existing viscoplastic polymer constitutive formulation is extended to more accurately account for the tension-compression asymmetry observed in the response of polymeric materials. A new plastic potential function is proposed, and elementary loading conditions are utilized to determine relations between model constants to ensure the potential function is positive valued. Expressions for the tensile and compressive plastic Poisson’s ratios are derived and used to determine bounds on model constants to ensure physically realistic plastic flow. The model is calibrated against experimental data across a range of strain rates, temperatures, and loading cases for a representative thermoset epoxy; good correlation between simulations and experimental data is obtained. Temperature rises due to the conversion of plastic work to heat are computed via the adiabatic heat energy equation. The viscoplastic polymer model is then implemented into the generalized method of cells micromechanics theory to investigate the effects of adiabatic heating on unidirectional composite response. Significant thermal softening due to the conversion of plastic work to heat is observed for matrix dominated deformation modes.

Original languageEnglish (US)
Title of host publicationAIAA Scitech 2019 Forum
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624105784
DOIs
StatePublished - Jan 1 2019
EventAIAA Scitech Forum, 2019 - San Diego, United States
Duration: Jan 7 2019Jan 11 2019

Publication series

NameAIAA Scitech 2019 Forum

Conference

ConferenceAIAA Scitech Forum, 2019
CountryUnited States
CitySan Diego
Period1/7/191/11/19

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ASJC Scopus subject areas

  • Aerospace Engineering

Cite this

Sorini, C., Chattopadhyay, A., & Goldberg, R. K. (2019). An improved unified viscoplastic polymer constitutive formulation for multiscale analysis of polymer matrix composites under high strain rate loading. In AIAA Scitech 2019 Forum (AIAA Scitech 2019 Forum). American Institute of Aeronautics and Astronautics Inc, AIAA. https://doi.org/10.2514/6.2019-0164