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Journal of Mechanical Science and Technology 24 (6) (2010) 1255~1260
www.springerlink.com/content/1738-494x
DOI 10.1007/s12206-010-0339-y
Evaluation of cyclic plasticity models of multi-surface and non-linear hardening by an energy-based fatigue criterion
Shahram Shahrooi*, Ibrahim Henk Metselaar and Zainul Huda
Center of Research for Advanced Materials, University of Malaya, Kuala Lumpur, Malaysia
(Manuscript Received June 8, 2009; Revised January 28, 2010; Accepted February 7, 2010)
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Abstract
This study examines the performance of four constitutive models according to capacity in predicting metal fatigue life under proportional and non-proportional loading conditions. These cyclic plasticity models are the multi-surface models of Mroz and Garud, and the non-linear kinematic hardening models of Armstrong-Frederick and Chaboche. The range of abilities of these models is studied in detail. Furthermore, the plastic strain energy under multiaxial fatigue condition is calculated in the cyclic plasticity models by the stress-strain hysteresis loops. Using the results of these models, the fatigue lives that have set in the energy-based fatigue model are predicted and evaluated with the reported experimental data of 1% Cr-Mo-V steel in the literature. Consequently, the optimum model in the loading condition for this metal is chosen based on life factor.
Keywords: Multi-surface plasticity model; Non-linear plasticity model; Energy-based fatigue model; Multiaxial fatigue ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1. Introduction
The study of multiaxial fatigue damage requires a thorough understanding of plasticity. Fatigue-crack initiation as controlled by local plasticity is a well-accepted phenomenon.Fatigue failure of mechanical components is a process comprising cyclic stress/strain evolutions and redistributions in the critical stressed volume. Due to stress concentration (notches, material defects, or surface roughness), the local material yields and redistributes the loading to the surrounding material, then follows it with cyclic plastic deformation. Finally, a crack is initiated leading to the loss of the resistance. Therefore, simulations for cyclic stress-strain evolution and redistribution are critical for predicting fatigue failure of mechanical components. Diverse criteria such as stress, strain, energy, and critical plane criterion have been utilized to estimate fatigue life of metals [1-6]. The earliest fatigue life prediction approach used the stress range as fatigue parameter for life correlations [7], and its models are suitable for high cycle fatigue.Soon after, the strain range was recognized as fatigue parameter for life prediction [8].
The parameters are typically associated with low cyclic fatigue. More recently,...