A study of a cyclic viscoplasticity model based on hyperbolic sine form for the inelastic strain rate

• Hyperbolic sine function was adopted to depict inelastic strain rate.
• All parameters were determined from monotonic and cyclic experiments.
• Hyperbolic sine function for strain rate may illustrate limit viscosity behavior.
• Cyclic visco-plasticity and stress relaxation behaviors were simulated.

The viscoplastic hyperbolic sine form which describes the inelastic strain rate is combined with the Ohno-Wang kinematic hardening rule. Experiments under monotonic tensile loads at different strain rates as well as under cyclic loadings are used to obtain all model parameters with the trial and error method. The effects of strain jumps of the stress, the saturated visco-plasticity behavior under cyclic loadings and the stress relaxation for several metallic materials are simulated. The usage of the exponential form instead of the hyperbolic sine form for the inelastic strain rate is discussed finally.