Nonlinear cumulative damage model and application to bridge fatigue life evaluation

Fatigue is a damage accumulation process in which material property deteriorates continuously. Fatigue life prediction issues are important for safety. This article aims to develop a nonlinear cumulative damage model. A fatigue damage model based on the continuum damage mechanics is addressed and applied to bridge fatigue life evaluation. First, the bridge nonlinear cumulative damage model based on damage mechanics is propounded and equivalent effective stress range is given. Then, the effects of the main parameter in the model are analyzed. Finally, Xinghai Bay Bridge is taken as a case study. The results indicate that the damage is increased with the material parameter [Formula: see text] reduced. [Formula: see text] is a material parameter depending on stress amplitude and without physical meaning. If [Formula: see text], the effect of [Formula: see text] is negligible. If [Formula: see text], nonlinear cumulative damage model degrades into Miner’s rule and effect of [Formula: see text] to structural damage is maximum. The cumulative damage curve calculated by the nonlinear cumulative damage model is nonlinear, with a low cumulative rate initially but a very high cumulative rate at the end of the design life, whereas the Miner’s rule is linear. The nonlinear cumulative damage model can reflect actual damage process, while Miner’s rule is pessimistic.

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Continuum Damage Mechanics Approach for Modeling Cumulative-Damage Model

Mathematical Problems in Engineering ◽

10.1155/2021/7136846 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Haoran Li ◽

Jiadong Wang ◽

Juncheng Wang ◽

Ming Hu ◽

Yan Peng

Keyword(s):

Fatigue Life ◽

Damage Mechanics ◽

Stress Amplitude ◽

Damage Model ◽

Continuum Damage Mechanics ◽

Cumulative Damage ◽

Continuum Damage ◽

Variable Loading ◽

Cumulative Damage Model ◽

Additional Hardening

In this study, we propose a novel cumulative-damage model based on continuum damage mechanics under situations where the mechanical components are subjected to variable loading. The equivalent completely reversed stress amplitude accounting for the effect of mean stress, stress gradients, loading history, and additional hardening behavior related to nonproportional loading paths on high-cycle fatigue under variable loading is elaborated. The effect of mean stress, stress gradients, loading history, and additional hardening behavior related to nonproportional loading paths is considered by averaging the superior limit of the intrinsic damage dissipation work in the critical domain. We developed a novel cumulative-damage model by introducing the equivalent completely reversed stress amplitude into the damage-evolution model. For better comparison, existing cumulative-damage models, including the Palmgren–Miner law, corrected Palmgren–Miner law, Morrow’s plastic work interaction rule, and Wang’s rule, were employed to predict the fatigue life under variable loading. The proposed model performed better, considering the error scatter band obtained by plotting the predicted and experimental fatigue life on the same coordinate system. The model precisely predicts fatigue life under variable loading and easily identifies its material constants.

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Prediction of combined cycle fatigue life of TC11 alloy based on modified nonlinear cumulative damage model

Chinese Journal of Aeronautics ◽

10.1016/j.cja.2020.10.021 ◽

2021 ◽

Author(s):

Zhenhua ZHAO ◽

Kainan LU ◽

Lingfeng WANG ◽

Lulu LIU ◽

Wei CHEN

Keyword(s):

Fatigue Life ◽

Damage Model ◽

Combined Cycle ◽

Cumulative Damage ◽

Cycle Fatigue ◽

Cumulative Damage Model

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Fatigue Life Estimation Using Frequency Domain Technique and Probabilistic Linear Cumulative Damage Model

10.1115/1.0000206v ◽

2021 ◽

Author(s):

Diego Burgos ◽

Vagner Pascualinotto Junior

Keyword(s):

Fatigue Life ◽

Frequency Domain ◽

Damage Model ◽

Cumulative Damage ◽

Life Estimation ◽

Fatigue Life Estimation ◽

Cumulative Damage Model

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Fatigue-Cumulative Damage Model of RC Crane Girders Strengthened with FRP Strips

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.385-387.165 ◽

2008 ◽

Vol 385-387 ◽

pp. 165-168

Author(s):

Shan Suo Zheng ◽

Bin Wang ◽

Lei Li ◽

Liang Zhang ◽

Pi Ji Hou

Keyword(s):

Damage Mechanics ◽

Flexural Rigidity ◽

Failure Process ◽

Damage Model ◽

Cumulative Damage ◽

Good Time ◽

Failure Patterns ◽

Damage And Fracture ◽

Cumulative Damage Model ◽

Frp Strips

The cumulative damage of the reinforced concrete (RC) crane girders occurred by overload, fatigue and other reasons in service may deteriorate the safety of RC crane girders seriously, so it is necessary to analyze the damage mechanism and rationally reinforce them in good time. In this paper, RC crane girder strengthened with CFRP strips is taken as a target, and the mechanical performance degradation under fatigue load is studied. According to the basic theory of continuum damage mechanics, a damage variable is defined by flexural rigidity, and fatigue- cumulative damage model, which describes the process of damage and fracture, is established. The variation law of cumulative damage of RC crane girders strengthened with FRP strips under crane load is discussed, and the failure patterns such as concrete cracking, debonding between CFRP strips and concrete, yield of steel bars etc., are studied. The criterion which can be used to estimate the cumulative damage degree of strengthened RC crane girders is proposed. Finally, the evolution of the fatigue damage in the RC crane girders strengthened with CFRP strips is numerically simulated, and the results show that the proposed model can correctly describe the damage and failure process of strengthened RC crane girders. The research will provide a reference for the damage analysis and reinforcement of RC crane girders strengthened with CFRP strips.

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Fatigue Design of Machine Elements Under Cumulative Damage Effect, Using Bagci’s Fatigue Failure Surface Line

Journal of Vibration and Acoustics ◽

10.1115/1.3269222 ◽

1984 ◽

Vol 106 (4) ◽

pp. 466-475

Author(s):

C. Bagci

Keyword(s):

Fatigue Life ◽

Fatigue Strength ◽

Material Properties ◽

Cumulative Damage ◽

Damage Effect ◽

Stress Effect ◽

Mean Stress ◽

Fatigue Design ◽

Miner’S Rule ◽

Miner's Rule

A thorough review of the state-of-the-art of determining fatigue life of machine and structural members considering cumulative damage effect under varying stress amplitudes is given. Among the many proposed theories, Miner’s linear damage rule is seen to be as reliable as any other rule alleged to be an improvement for predicting fatigue life under cumulative damage effects. Its simplicity and amenability for easy modification have in fact been the basis for some other theories and used in design codes. In its original form, Miner’s rule, however does not account for fatigue strength reducing factors. Observing fatigue data on the effects of fatigue strength reducing factors, the article offers a modified form of the Miner’s rule to consider the effects of fatigue strength reducing factors, such as the notch, reliability, surface finish, size, and environmental factors. The mean stress effect and material properties are incorporated utilizing Bagci’s mean stress line and the S-N diagram. The safe fatigue life of a component subjected to stresses of varying magnitudes becomes Ns=df/∑i=1s(αi/10zi) where zi=A{B−log(pig/Rf)+log[1−(pi/mi)r]} in the ith block of stress range, Rf being the resultant of fatigue strength reducing factors; A, B, g are parameters defined by material properties, pi is the ratio of the basic alternating stress times the factor of safety (the failure value) to the yield strength of the material, and mi is the slope of the load line in the ith block of loading. Design charts for zi for steel and aluminum alloys for cases with and without basic mean stress for r=4 are given. Numerical examples are included. Therefore, the article offers the most general form of the Miner’s rule for designers’ use for fatigue design considering cumulative damage effect.

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