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Constitutive Modeling and Failure Criteria of Carbon-Fiber Reinforced Polymers Under High Strain Rates

Karim, Mohammed Rezaul

Abstract Details

2005, Doctor of Philosophy, University of Akron, Mechanical Engineering.
Dynamic constitutive model and failure criteria were developed to predict impact perforation of laminated polymer matrix composite material under projectile loading. It was assumed that the rate-dependent characteristics of the composite can be described by time-dependent or viscoelastic property of the polymer matrix. Relaxation functions were used to derive a time-dependent stiffness matrix for a unidirectional IM6G/3501-6 carbon/epoxy laminate. The epoxy was represented as a Maxwell element in parallel with a linear spring, while the carbon was modeled as a linear spring. The viscoelastic properties of the epoxy were obtained by fitting the constitutive equations to the experimental data at a constant strain rate. The Hashin’s 3D failure criteria were used to predict the dynamic failure of composite by replacing quasi-static strength properties with rate-dependent strength properties. The dynamic constitutive equations were incorporated into LS-DYNA3D via a user-defined material subroutine and used to predict the transient response of a 32 ply AS4/3501-6 carbon/epoxy laminate under projectile loading. The maximum contact force between the projectile and laminate was found to be only 7% higher than the experimental data. The dynamic failure criterion was also incorporated into LS-DYNA to simulate damage of an AS4/3501-6 carbon/epoxy laminate. The FEA program was able to simulate expected tensile fracture and transverse shear failure modes of a thin and thick ply during projectile impact. A full ballistic impact simulation was also done on a graphite/epoxy (AS4/3501-6) laminate. Residual velocities were evaluated for different striking velocities and the FEA results were at most 8 % higher than the experimental data.
Michelle Hoo Fatt (Advisor)
105 p.

Recommended Citations

Citations

  • Karim, M. R. (2005). Constitutive Modeling and Failure Criteria of Carbon-Fiber Reinforced Polymers Under High Strain Rates [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1133888817

    APA Style (7th edition)

  • Karim, Mohammed. Constitutive Modeling and Failure Criteria of Carbon-Fiber Reinforced Polymers Under High Strain Rates. 2005. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1133888817.

    MLA Style (8th edition)

  • Karim, Mohammed. "Constitutive Modeling and Failure Criteria of Carbon-Fiber Reinforced Polymers Under High Strain Rates." Doctoral dissertation, University of Akron, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1133888817

    Chicago Manual of Style (17th edition)