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High-temperature components, for example turbochargers, are often subject to complex thermal and mechanical loading paths. Non-uniform temperature distribution and constraints by neighboring components result in complex timely varying stress and strain states during operation. The aim of this paper is to analyze inelastic behavior of a casting material Ni-resist D-5S in a wide stress, strain rate and temperature ranges. The material model including a constitutive equation for the inelastic strain rate tensor and a non-linear kinematic hardening rule is discussed. To calibrate the model, experimental databases from creep and low cycle fatigue tests are generated. They include creep curves for temperatures within the range 600–800 °C and stress levels from 10 to 150 MPa. The low cycle fatigue data collect a family of hysteresis loops for the strain rate of 10−3 1/s, the strain amplitude from 0.4% to 2% and temperature levels within the range 200–800 °C. For the verification of the model, simulations of the material behavior under uniaxial thermo-mechanical fatigue loading conditions are performed. The results for the stress response are compared with experimental data.

The aim of this paper is to present experimental data and the constitutive model for the inelastic behavior of polyoxymethylene in wide strain rate and temperature ranges. To capture the non-linearity of the stress responses for both loading and unloading regimes, the composite model of inelastic deformation is utilized and further developed. The equivalent inelastic strain rate is described by the Prandtl–Eyring law, while the temperature dependence is characterized by the modified Arrhenius-type law. Generalized equivalent stress and the flow rule are formulated to capture pressure sensitivity, transverse strain and volumetric strain responses. The results obtained by the constitutive law are compared with experimental data for stress vs. axial strain from standard tension tests as well as with axial and transverse strains measured by digital image correlation. The developed composite model is able to capture the non-linearity of stress–strain curves for complex loading paths within the small strain regime. For higher strains, apart from geometrically non-linear theory, evolution laws for the volume fraction of the constituents should be modified and calibrated. For the small strain regime, the inelastic dilatation is negligible. For higher axial strain values, a decrease in Poisson’s ratio under tension and increase in it under compression are observed. The Drucker–Prager-type equivalent stress and the developed flow rule provide a better description of both the transverse and volumetric strains than that of the classical von Mises–Odqvist flow rules.

An experimental and numerical study of the mechanical behaviour of cast iron during a thermomechanical fatigue is presented here. The cast iron specimens under investigation were made of austenitic ductile iron Ni-resist Type D-5S which is mostly used for exhaust manifolds and turbocharger housings. Elastoplastic and viscoplastic material parameters were determined from low cycle fatigue tests at different strain rates and thermomechanical fatigue tests, respectively, and then compared to material parameters previously gained by a combination of low cycle fatigue tests at a single strain rate and creep tests. These material parameters were then used to perform thermal and structural finite element analyses from which fatigue and creep damages on the cast iron were calculated. While damage predictions calculated here vary, they are comparable to experimental observations.