New strain energy-based critical plane approach for multiaxial fatigue life prediction

2019 ◽  
Vol 54 (5-6) ◽  
pp. 310-319
Author(s):  
Meng-Fei Hao ◽  
Shun-Peng Zhu ◽  
Ding Liao
Keyword(s):  
Fatigue Life ◽  
Strain Energy ◽  
Equivalent Stress ◽  
Equivalent Strain ◽  
Damage Parameter ◽  
Multiaxial Fatigue ◽  
Critical Plane ◽  
Critical Plane Approach ◽  
Energy Aspect ◽  
Life Predictions

Based on critical plane approach, this article develops a new damage parameter through combing the equivalent strain energy aspect for multiaxial fatigue analysis, which includes no additional fitted parameters and overcomes the deficiency of using only equivalent stress/strain criterion separately under multiaxial loadings. Then, experimental data of GH4169, TC4, Al 7050-T7451 alloys under different loading conditions are applied for model validation and comparison with other four models. Results indicate that the proposed damage parameter yields better multiaxial fatigue life predictions than others.

Damage Mechanics and Critical Plane Approach to Multiaxial Fatigue

2013 ◽  
Vol 592-593 ◽  
pp. 239-245
Author(s):  
Roberto Brighenti ◽  
Andrea Carpinteri
Keyword(s):  
Fatigue Life ◽  
Damage Mechanics ◽  
Crack Nucleation ◽  
Fatigue Loading ◽  
Fatigue Behaviour ◽  
Damage Parameter ◽  
Multiaxial Fatigue ◽  
Critical Plane ◽  
Critical Plane Approach ◽  
Scalar Damage Parameter

The mechanical behaviour of structural components subjected to multiaxial fatigue loading is very important in modern design. Several approaches have been introduced in recent decades to analyse this problem. The so-called critical plane approach, based on the stresses acting on the plane where the crack nucleation is expected to occur, is widely used. This criterion can give us a fatigue damage measurement, which can be used to evaluate fatigue life. On the other hand, fatigue life under general multiaxial stress histories can also be assessed by applying the damage accumulation method. In such a method, a scalar damage parameter is quantified through the damage increments which develop during the fatigue process up to the critical damage value corresponding to the final failure of the structures. The damage increment approach to fatigue has recently been discussed and connected to the classical crack propagation approach. In the present paper, the interpretation of the critical plane approach based on the continuum damage mechanics concepts is examined. In particular, the physical meaning of the critical plane approach is shown, that is, such an approach can be interpreted as a damage method which takes into account the scalar damage parameter evaluated along preferential directions. Finally, the fatigue behaviour of a metallic material under multiaxial cyclic load histories is analysed through the two above approaches.

scholarly journals Multiaxial Fatigue Life Calculation Model for Engineering Components in Rolling-Sliding Contact

2018 ◽  
Vol 188 ◽  
pp. 02016
Author(s):  
Robert Basan ◽  
Tea Marohnić
Keyword(s):  
Fatigue Life ◽  
Complex Geometry ◽  
Calculation Model ◽  
Multiaxial Fatigue ◽  
Sliding Contact ◽  
Engineering Practice ◽  
Critical Plane ◽  
Principal Axes ◽  
Critical Plane Approach ◽  
Crack Initiation Criterion

Number of important engineering components and elements such as gears, rollers, bearings operate in conditions of rolling-sliding contact loading. Determination of fatigue lives of such components and elements is very important for engineering practice but remains quite chalenging task due to complex states of stress and strain in the material in the vicinity of contact (multiaxiality, non-proportionality, rotation of principal axes, mean compressive stress) as well as complex contact conditions such as loading amplitude, complex geometry of bodies in contact, type of lubrication, value of coefficient of friction, etc. Proposed fatigue life calculation model for cases of rolling-sliding contact is based on critical plane approach in the form of Fatemi-Socie crack initiation criterion. Developed model was implemented in the case of gears teeth flanks in mesh and compared with results and fatigue lives of gears reported in literature. Good agreement was determined confirming validity of developed model. Further advantage of presented approach and developed model is obtained information on critical location(s) and critical plane(s) orientation which can subsequently be used for estimation of crack shapes in initial phases of their growth and later damage type into which they can be expected to develop.

Multiaxial Fatigue Life Estimation in the Absence of Fatigue Properties: A Case Study on a Turbine Rotor Used in a Typical Turbo Shaft Engine

2015 ◽  
Author(s):  
Dileep Sivaramaiyer ◽  
Esakki Muthu Shanmugam ◽  
Palani Udayanan ◽  
Girish K. Degaonkar
Keyword(s):  
Fatigue Life ◽  
Turbine Rotor ◽  
Equivalent Strain ◽  
Multiaxial Fatigue ◽  
Strain Response ◽  
Approximation Techniques ◽  
Damage Models ◽  
Von Mises ◽  
Life Predictions ◽  
Strain Model

Complex stress strain response of a turbine rotor used in a gas turbine engine was studied. Simple and comprehensive approximation techniques developed by Muralidharan–Manson, Bäumel-Seeger (from data obtained from tension tests) and Roessle–Fatemi (from data obtained from hardness tests) were used to predict the fatigue constants of the rotor material. Multiaxial Fatigue damage models like von Mises equivalent strain model, Smith Watson Topper model, Fatemi–Socie Model, Kandil Brown and Miller model were used to predict the fatigue life of the rotor. Predictions were then compared with the life obtained from the same damage models using the experimental fatigue constants and the life obtained from Low Cycle Fatigue (LCF) testing of the turbine rotor. Acceptable life predictions were obtained with SWT model and FS model using the fatigue constants obtained from the experiment as well as from the approximation techniques. von-Mises equivalent strain model failed to give reasonable life predictions with fatigue constants obtained from the experiment and approximation techniques. The life predicted by KBM model using fatigue constants obtained from approximation techniques (Bäumel-Seeger and Roessle-Fatemi) was found unsatisfactory. The approximation technique proposed by Muralidharan-Manson in combination with all the damage models fitted the failure data within a factor of 5. Finite Element tools were used to determine the stress/strain response of the component under the mutiaxial loading condition.

A New Multiaxial Fatigue Life Prediction Model Under Proportional and Nonproportional Loading

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Jing Li ◽  
Qiang Sun ◽  
Zhong-Ping Zhang ◽  
Chun-Wang Li ◽  
Dong-Wei Zhang
Keyword(s):  
Fatigue Life ◽  
Damage Model ◽  
Cyclic Hardening ◽  
Damage Parameter ◽  
Multiaxial Fatigue ◽  
Life Assessment ◽  
Normal Strain ◽  
Critical Plane ◽  
Nonproportional Loading ◽  
Fatigue Life Assessment

Based on the critical plane approach, the drawbacks of the Wang–Brown (WB) model are analyzed. It is discovered that the normal strain excursion in the WB model cannot account for the additional cyclic hardening well. In order to solve this problem, a new damage parameter for multiaxial fatigue is proposed. In the meantime, the procedure for multiaxial fatigue life assessment incorporating critical plane damage model is presented as well. In the new damage parameter, both strain and stress components are considered, and the effect of the additional cyclic hardening on the fatigue life during nonproportional loading is taken into account as well. In addition, the proposed model is modified when the mean stress is existence. It is convenient for engineering application because of no material constants in this parameter. The capability of fatigue life assessment for the proposed fatigue damage model is checked against the experimental data found in literature for tubular specimens of 1045HR steel, hot-rolled 45 steel, S460N steel, GH4169 alloy at elevated temperature, and the notched shaft of SAE 1045 steel, which is under cyclic bending and torsion loading. It is demonstrated that the proposed criterion gives satisfactory results for all the five checked materials.

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