A continuum damage model for weld heat affected zone under low cycle fatigue loading

The forging die material, a high strength steel designated W513 is considered in this paper. A fatigue damage model, based on thermodynamics and continuum damage mechanics, is constructed in which both the previous damage and the loading sequence are considered. The unknown material parameters in the model are identified from low cycle fatigue tests. Damage evolution under multi-level fatigue loading is investigated. The results show that the fatigue life is closely related to the loading sequence. The fatigue life of the materials with low fatigue loading first followed by high fatigue loading is longer than that for the reversed loading sequence.

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An anisotropic continuum damage model for high-cycle fatigue

Mechanics of Advanced Materials and Structures ◽

10.1080/15376494.2019.1697472 ◽

2020 ◽

pp. 1-15

Author(s):

Liang Zhang ◽

Zhenyuan Gao ◽

Robert A. Haynes ◽

Todd C. Henry ◽

Wenbin Yu

Keyword(s):

High Cycle Fatigue ◽

Damage Model ◽

Continuum Damage ◽

Cycle Fatigue ◽

Continuum Damage Model

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Fatigue Crack Modeling and Simulation Based on Continuum Damage Mechanics

Journal of Pressure Vessel Technology ◽

10.1115/1.2388993 ◽

2006 ◽

Vol 129 (1) ◽

pp. 96-102 ◽

Cited By ~ 3

Author(s):

Masakazu Takagaki ◽

Toshiya Nakamura

Keyword(s):

Fatigue Crack ◽

Crack Propagation ◽

Fatigue Crack Propagation ◽

Damage Mechanics ◽

Low Cycle Fatigue ◽

Continuum Damage Mechanics ◽

Fatigue Loading ◽

Present Theory ◽

Continuum Damage ◽

Cycle Fatigue

Numerical simulation of fatigue crack propagation based on fracture mechanics and the conventional finite element method requires a huge amount of computational resources when the cracked structure shows a complicated condition such as the multiple site damage or thermal fatigue. The objective of the present study is to develop a simulation technique for fatigue crack propagation that can be applied to complex situations by employing the continuum damage mechanics (CDM). An anisotropic damage tensor is defined to model a macroscopic fatigue crack. The validity of the present theory is examined by comparing the elastic stress distributions around the crack tip with those obtained by a conventional method. Combined with a nonlinear elasto-plastic constitutive equation, numerical simulations are conducted for low cycle fatigue crack propagation in a plate with one or two cracks. The results show good agreement with the experiments. Finally, propagations of multiply distributed cracks under low cycle fatigue loading are simulated to demonstrate the potential application of the present method.

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Process Induced Residual Stress Effect on Fatigue Lifetime of Automotive Steel Components

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.996.808 ◽

2014 ◽

Vol 996 ◽

pp. 808-813

Author(s):

Elias Merhy ◽

Ngadia Taha Niane ◽

Bastien Weber ◽

Philippe Bristiel

Keyword(s):

Residual Stress ◽

Heat Affected Zone ◽

High Cycle Fatigue ◽

Low Cycle Fatigue ◽

Welding Process ◽

Fatigue Loading ◽

Stress Effect ◽

Cycle Fatigue ◽

Residual Stress Field ◽

Fatigue Lifetime

Metal Active Gas (MAG) welding process of steel sheets generates, in the vicinity of the welding joint, the well-known Heat Affected Zone (HAZ) in which the material presents more microstructural defects compared to the original metal. Since high cycle fatigue is largely dependent on the material microstructure features, the HAZ is considered as the weakest zone under high cycle fatigue loading. In addition, the welding causes, in the Heat Affected Zone, irreversible plastic strains that induce important residual stress fields in this critical zone of the structure. Therefore, in order to properly predict the high cycle fatigue life time of the welded automotive components, it is of primordial importance to first identify and then consider, if necessary, the welding induced residual stress field in the structure modeling. In this work, it is found that residual stresses have non-negligible impact on high cycle fatigue lifetime, while its effect is minor in the low cycle fatigue domain.

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