Ramberg-Osgood Plasticity

The response of the matrix constituent material is provided by a Ramberg-Osgood plasticity model that is enhanced to show sensitivity to the direction of loading relative to the fiber direction. You can use the HIN file to adjust the four plasticity parameters (σ0, n, α, β) and the largest fiber orientation eigenvalue (λI) that were optimized during material characterization.

*RAMBERGOSGOOD
sigma_0, n, alpha, beta, eig

where sigma_0 is the yield strength of the matrix, n is the hardening parameter, alpha and beta are the weighting coefficients, and eig is the largest fiber orientation eigenvalue. Refer to The Rupture Model section of the Theory Manual for more information. The *RAMBERGOSGOOD keyword must be preceded by a valid *MATERIAL or *ENVIRONMENT keyword.

Consider the following example where we adjust the yield strength and the hardening parameter for our material in hopes of obtaining a better fit to the experimental stress-strain data. We will specify a yield strength of 71MPa and a hardening parameter of 8.0.

*MATERIAL, NAME=CA-PLASTIC-1
*RAMBERGOSGOOD
71, 8.0, , ,