Development of an Improved High Cycle Fatigue Criterion
01 Jan 2007-Journal of Engineering for Gas Turbines and Power-transactions of The Asme (American Society of Mechanical Engineers)-Vol. 129, Iss: 1, pp 162-169
TL;DR: In this paper, an integrated computational-experimental approach for prediction of total fatigue life applied to a uniaxial stress state is developed, which consists of the following elements: (1) development of a vibration based fatigue testing procedure to achieve low cost bending fatigue experiments and (2) developing of a life prediction and estimation implementation scheme for calculating effective fatigue cycles.
Abstract: An integrated computational-experimental approach for prediction of total fatigue life applied to a uniaxial stress state is developed. The approach consists of the following elements: (1) development of a vibration based fatigue testing procedure to achieve low cost bending fatigue experiments and (2) development of a life prediction and estimation implementation scheme for calculating effective fatigue cycles. A series of fully reversed bending fatigue tests were carried out using a vibration-based testing procedure to investigate the effects of bending stress on fatigue limit. The results indicate that the fatigue limit for 6061-T6 aluminum is approximately 20% higher than the respective limit in fully reversed tension-compression (axial). To validate the experimental observations and further evaluate the possibility of prediction of fatigue life, an improved high cycle fatigue criterion has been developed, which allows one to systematically determine the fatigue life based on the amount of energy loss per fatigue cycle. A comparison between the prediction and the experimental results was conducted and shows that the criterion is capable of providing accurate fatigue life prediction.
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TL;DR: In this paper, a new energy-based life prediction framework for calculation of axial and bending fatigue results at various stress ratios has been developed, which is capable of constructing prediction intervals based on a specified percent confidence level.
Abstract: A new energy-based life prediction framework for calculation of axial and bending fatigue results at various stress ratios has been developed. The purpose of the life prediction framework is to assess the behavior of materials used in gas turbine engines, such as Titanium 6Al-4V (Ti 6AI-4V) and Aluminum 6061-T6 (Al 6061-T6). The work conducted to develop this energy-based framework consists of the following entities: (1) a new life prediction criterion for axial and bending fatigue at various stress ratios for Al 6061-T6, (2) the use of the previously developed improved uniaxial energy-based method to acquire fatigue life prior to endurance limit region (Scott-Emuakpor et al., 2007, "Development of an Improved High Cycle Fatigue Criterion, " ASME J. Eng. Gas Turbines Power, 129, pp. 162-169), (3) and the incorporation of a probabilistic energy-based fatigue life calculation scheme to the general uniaxial life criterion (the first entity of the framework), which is capable of constructing prediction intervals based on a specified percent confidence level. The precision of this work was verified by comparison between theoretical approximations and experimental results from recently acquired Al 606-T6 and Ti 6Al-4V data. The comparison shows very good agreement, thus validating the capability of the framework to produce accurate uniaxial fatigue life predictions for commonly used gas turbine engine materials.
62 citations
22 Jan 2021
TL;DR: This review article aims to provide a comprehensive overview of the state-of-the art in cumulative damage and lifetime prediction models for endurance based high-cycle fatigue design of metal structures.
Abstract: Fatigue design of engineering structures is typically based on lifetime calculation using a cumulative damage law. The linear damage rule by Miner is the universal standard for fatigue design even though numerous experimental studies have shown its deficiencies and possible non-conservative outcomes. In an effort to overcome these deficiencies, many nonlinear cumulative damage models and life prediction models have been developed since; however, none of them have found wide acceptance. This review article aims to provide a comprehensive overview of the state-of-the art in cumulative damage and lifetime prediction models for endurance based high-cycle fatigue design of metal structures.
51 citations
TL;DR: In this article, an energy-based fatigue life prediction framework was developed for calculation of remaining fatigue life of in-service gas turbine materials, which can account aging effect caused by cyclic loadings on fatigue strength of gas turbine engines structural components.
Abstract: An energy based fatigue life prediction framework has been developed for calculation of remaining fatigue life of in service gas turbine materials. The purpose of the life prediction framework is to account aging effect caused by cyclic loadings on fatigue strength of gas turbine engines structural components which are usually designed for very long life. Previous studies indicate the total strain energy dissipated during a monotonic fracture process and a cyclic process is a material property that can be determined by measuring the area underneath the monotonic true stress-strain curve and the sum of the area within each hysteresis loop in the cyclic process, respectively. The energy-based fatigue life prediction framework consists of the following entities: (1) development of a testing procedure to achieve plastic energy dissipation per life cycle and (2) incorporation of an energy-based fatigue life calculation scheme to determine the remaining fatigue life of in-service gas turbine materials. The accuracy of the remaining fatigue life prediction method was verified by comparison between model approximation and experimental results of Aluminum 6061-T6. The comparison shows promising agreement, thus validating the capability of the framework to produce accurate fatigue life prediction.
45 citations
Cites methods from "Development of an Improved High Cyc..."
...In addition, based on the previously developed energy-based fatigue criterion [4, 5 , 7] improvements were made to provide the criterion with the capability of estimating fatigue life of in-service parts....
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...This method consists of the following capabilities: uniaxial fatigue life at various stress ratios [4], tension/compression fatigue life prediction [ 5 ], bending fatigue life prediction [6], and shear fatigue life prediction [7]....
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...the minimum fully reversed point is observed as the origin), E is the modulus of elasticity, and the variables σ0, σc, e0 and C are curve fit parameters described in [ 5 ]....
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...Based on this theory, an improved energy-based criterion has been developed to systematically determine fatigue life based on the amount of energy loss per fatigue cycle [4, 5 ]....
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TL;DR: In this paper, a continuum formulation for irreversible energy dissipation that accounts for generated acoustic emissions during the loading of the materials is proposed, and the evolution of the dissipative energy is experimentally measured as the material is degraded.
37 citations
TL;DR: In this article, a strain energy-based method was developed to predict the fatigue life of a structure subjected to either shear or biaxial bending loads at various stress ratios, where the experimental strain energy density of each can be determined by measuring the area underneath the monotonic true stress-strain curve and the area within a hysteresis loop, respectively.
Abstract: A strain-energy-based method has been developed to predict the fatigue life of a structure subjected to either shear or biaxial bending loads at various stress ratios. The framework for this method is an advancement of previously conducted research that validates a uniaxial energy-based fatigue-life-prediction approach. The understanding behind the approach states that the total strain energy dissipated during a monotonic fracture and a cyclic process is the same material property, where the experimental strain-energy density of each can be determined by measuring the area underneath the monotonic true stress-strain curve and the area within a hysteresis loop, respectively. The developed framework consists of two elements: a life-prediction method that calculates shear fatigue-life cycles and a multi-axial life-prediction method capable of calculating biaxial fatigue-life cycles. A comparison was made between the two framework elements and experimental results from three different aluminum alloys. The comparison shows encouraging agreement, thus providing credence in the prediction capabilities of the proposed energy-based framework.
35 citations
Cites background or methods or result from "Development of an Improved High Cyc..."
...(1–3) with experimental low-cycle and monotonic-tensile experimental results [10,12]....
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...Based on this understanding, an energy-based fatigue-life-prediction method with the capability of accurately predicting uniaxial fatigue life (bending and tension/ compression) at various stress ratios was developed [10,11]....
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...(5) [10]....
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...(3) after all necessary derivations]; E is the modulus of elasticity, and the variables c, o, "o, andC are curve-fit parameters [10]....
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...(3) is the stress–strain relation used to construct one cyclic (hysteresis) loop [9,10]....
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References
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01 Mar 1989
TL;DR: The Manufacturing Engineering & Technology, 6/e, the authors provides a mostly qualitative description of the science, technology, and practice of manufacturing, including detailed descriptions of manufacturing processes and the manufacturing enterprise.
Abstract: For courses in manufacturing processes at two- or four-year schools. An up-to-date text that provides a solid background in manufacturing processes. Manufacturing Engineering & Technology, 6/e, presents a mostly qualitative description of the science, technology, and practice of manufacturing. This includes detailed descriptions of manufacturing processes and the manufacturing enterprise that will help introduce students to important concepts. With a total of 120 examples and case studies, up-to-date and comprehensive coverage of all topics, and superior two-color graphics, this text provides a solid background for manufacturing students and serves as a valuable reference text for professionals. The Sixth Edition has been completely updated, and addresses issues essential to modern manufacturing, ranging from traditional topics such as casting, forming, machining, and joining, to advanced topics such as the fabrication of microelectronic devices and microelectromechanical systems (MEMS), and nanomaterials and nanomanufacturing.
1,947 citations
TL;DR: In this paper, an energy criterion for fatigue failure is proposed, based on a relation between stress amplitude and the number of cycles to failure which utilizes only material properties obtained from the static true stress-strain tension test.
Abstract: In this paper an energy criterion for fatigue failure is postulated. Microplastic strain hysteresis energy is considered to be an index for fatigue damage. On this basis, a relation is developed between stress amplitude and the number of cycles to failure which utilizes only material properties obtained from the static true stress-strain tension test. The analysis is found to compare well with an experimentally determined S-N curve for SAE 4340 steel.
230 citations
TL;DR: In this paper, a topological design procedure, incorporating a finite element model, was proposed to produce the shape of the sample necessary to achieve the required stress state/pattern, and a forced vibration-based fatigue procedure for conducting the high cycle fatigue experiments with variable-amplitude loading.
129 citations
01 Jan 1999
128 citations
TL;DR: In this paper, high temperature total endurance tests were conducted on three alloys (316L steel at 550°C, 9Cr-1Mo steel and Nimonic 101 at 850°C) in low cycle fatigue under continuous cycling.
Abstract: High temperature total endurance tests were conducted on three alloys (316L steel at 550°C; 9Cr–1Mo steel at 550°C; Nimonic 101 at 850°C) in low cycle fatigue under continuous cycling. The austenitic steel was observed to cyclically harden, whereas the ferritic steel and the superalloy both cyclically softened. Methods for rationalising evolutionary behaviour were variation of percentage hardening/softening with strain range, cumulative ductility criterion, variation of secant modulus in the hysteresis loops, and cumulative energy criterion. The energy expended per cycle appears to be the most attractive. For a given strain range this was approximately constant at any stage of evolution. More significantly, the cumulative energy at saturation was constant, approximately independent of total strain range, and about 0·5–3·0 J mm−3 according to the material used. The Palmgren–Miner hypothesis (which is widely used in summing fatigue damage) was originally derived on an energy argument and it is propo...
119 citations