Dec 17, 2001 high cycle fatigue is associated with low loads and long life. An overall building block approach facilitated the development and adaptation of models for immediate application to each of the three inservice generated damage states the foreign object damage fod and fretting damage models are dependent on the low cycle fatigue high cycle fatigue lcfhcf and baseline models. Fatigue design approaches hcflcf if the amplitude of the total strain is such that we have significant plasticity, the lifetime is likely to be short low cycle fatigue or lcf. Historically, fatigue has been separated into regions of high cycle fatigue that require more than 10 4 cycles to failure where stress is low and primarily elastic and low cycle fatigue where there is significant plasticity. Probabilistic methods have recently been widely used to account for the uncertainty in the fatigue life prediction of structures or materials. A new high cycle fatigue life prediction model of fv520bi, taking surface roughness as a main effective variable is proposed. The life prediction methodology has been implemented in abaqus and validated against direct cyclebycycle simulations. Improved highcycle fatigue hcf life prediction request pdf. Prediction of fatigue life of smooth specimens of sg iron by using a fracture mechanics approach. The predicted result of high cycle fatigue life of matrix alloy al6061 is compared with. Pdf hightemperature low cycle fatigue life prediction. Life prediction for variable amplitude servicetype load histories is considered in some detail. Request pdf improved highcycle fatigue hcf life prediction an overall building block approach facilitated the development and adaptation of models for immediate application to each of the.
In high cycle fatigue situations, materials performance is commonly characterized by an sn curve, or stresscycle curve, or fatigue curve, also known as a wohler curve. This has been the approach used in the prediction of lowcycle thermal fatigue in the past, and will ltkely remain as such for a number of years. Generally, the life prediction of elements subjected to fatigue is based on the safelife approach, coupled with the rules of linear cumulative damage palmgren andminer. E n the fatigue life in the plastic part can be approximated by. Probabilistic high cycle fatigue life prediction for gas. Development of a high cycle fatigue life prediction model. Generally, the life prediction of elements subjected to fatigue is based on the safe life approach, coupled with the rules of linear cumulative damage palmgren andminer. Solid mechanics low cycle fatigue lcf anders ekberg 5 8 coffin manson design rule for the elastic part, the relationship between strain amplitude and fatigue life can be approximated by. Fatigue life prediction using 2scale temporal asymptotic. Based on the assumption of quasibrittle failure under high cycle fatigue for the metal material, the damage constitutive equation and the modified damage evolution equation are obtained with continuum damage mechanics. Low cycle fatigue behavior of thick high strength steel plates for pressure vessels. A probabilistic framework for low cycle fatigue life prediction and uncertainty modeling of turbine disk alloys.
Based on the assumption of quasibrittle failure under highcycle fatigue for the metal material, the damage constitutive equation and the modified damage evolution equation are obtained with continuum damage mechanics. Lowcycle fatigue behavior of welded joints in highstrength steels. High cycle fatigue life prediction and reliability analysis of aeroengine blades article pdf available in transactions of tianjin university 186 december 2012 with 94 reads. The fatigue failure analysis and fatigue life prediction. Fatigue failures, both for high and low cycle, all follow the same basic steps. Revised damage evolution equation for high cycle fatigue life. Multiaxial highcycle fatigue life prediction model based on. In spite of this clear industrial need, until now modeling of metal behavior in a highcycle fatigue regime was often based on empirical approaches. Highcycle fatigue life prediction for pbfree bga under random vibration loading. This study provides novel insights into the evolution mechanism of hcf damage. Jul 22, 2015 the fatigue life prediction for components is a difficult task since many factors can affect the final fatigue life.
A criterion for high cycle fatigue life and fatigue limit prediction in biaxial loading conditions article pdf available in acta mechanica sinica 324. Definition of the fatigue life the number of cycles at which the peak tensile stress during each cycle dropped by 25% from its initial value japanese industrial standards z22791992. Phasefield model for high cycle fatigue life prediction of brittle materials karlo seles,1, fadi aldakheel2, nenad gubeljak3, zdenko tonkovic1 and jurica soric1 1 faculty of mechanical engineering and naval architecture, university of zagreb, ivana lucica 5. Bayesian framework for probabilistic low cycle fatigue life prediction and uncertainty modeling of aircraft turbine disk alloys shunpeng zhua, hongzhong huanga,n, reuel smithb, victor ontiverosb, liping hea, mohammad modarresb a school of mechanical, electronic, and industrial engineering, university of electronic science and technology of china, no. Then, finite element method fem is used to describe the failure process of metal material.
Phasefield model for high cycle fatigue life prediction of. Metallic materials are extensively used in engineering structures and fatigue failure is one of the most common failure modes of metal structures. Structures, structural dynamics, and materials and colocated conferences home. A new highcycle fatigue life prediction model of fv520bi, taking surface roughness as a main effective variable is proposed. This is a graph of the magnitude of a cyclic stress s against the logarithmic scale of cycles to failure n. A modified fatigue damage model for highcycle fatigue life. Lowcycle fatigue loading that typically causes failure in less than 10 4 cycles is associated with localized plastic behavior in metals. Many studies have been carried out, particularly in the last 50 years on metals and the relationship between temperature, stress, and number of cycles to failure.
Fatigue life prediction of high temperature components in. Research article a modified fatigue damage model for high cycle fatigue life prediction mengwang, 1,2 qingguofei, 1,2 andpeiweizhang 1,2 department of engineering mechanics, southeast university, nanjing, china jiangsu key laboratory of engineering mechanics, nanjing, china correspondence should be addressed to qingguo fei. High cycle fatigue life prediction of al6061tib2 insitu. A mechanismbased model for tmf fatigue life prediction of high temperature automobile components was proposed in 8. In the light of the above this paper focuses on prediction of high cycle fatigue life of al6061 tib2 insitu composites by using commercial fea software mscpatran, mscnastran and mscfatigue. Article very high cycle fatigue failure analysis and life prediction of crniw gear steel based on crack initiation and growth behaviors hailong deng 1, wei li 1, tatsuo sakai 2 and zhenduo sun 1 received. Dr theodore nicholas ran the high cycle fatigue program for the us air force between 1995 and 2003 at wrightpatterson air force base, and is one of the worlds leading authorities on the subject, having authored over 250 papers in leading archival journals and books. Damage mechanicsbased models for highcycle fatigue life.
The existing veryhighcycle fatigue life model is not wellfit for highcycle fatigue model of fv520bi. Revised damage evolution equation for high cycle fatigue. Fatigue phenomena occur when a material is subjected to fluctuating stresses and strains, which lead to failure due to damage accumulation. Different methods, including the palmgrenminer linear damage rule ldr based, multiaxial and variable. The increment of specimens life and damage state can be researched using damage. A modified fatigue damage model for highcycle fatigue. It is suggested that life predictions which consider both crack initiation and crack growth are often appropriate. Jun 26, 2018 the fatigue characteristics of microelectromechanical systems mems material, such as silicon or polysilicon, have become very important. Research article a modified fatigue damage model for highcycle fatigue life prediction mengwang, 1,2 qingguofei, 1,2 andpeiweizhang 1,2 department of engineering mechanics, southeast university, nanjing, china jiangsu key laboratory of engineering mechanics, nanjing, china correspondence should be addressed to qingguo fei.
The sn curve in the high cycle region is sometimes described by the basquin equation. For example, in a normal environment, under 120ksi alternating stress, alloy a would fail at about 10,000 cycles. The term cycle refers to repeated applications of stress that lead to eventual fatigue and failure. Advanced high cycle fatigue hcf life assurance methodologies. Low cycle fatigue lcf usually refers to situations where the stress is high enough for plastic deformation to occur, the accounting of the loading in terms of stress is less useful and the stain in the material offers a simpler and more accurate description. If the stresses are low enough that the strains are elastic, the lifetime is likely to be long high cycle fatigue 25 or hcf. Development of a high cycle fatigue life prediction model for. Fatigue at high temperature is a complex phenomenon as it is influenced by a number of timedependent processes which become important at elevated temperatures. Pdf high cycle fatigue life prediction and reliability.
The fatigue life prediction for components is a difficult task since many factors can affect the final fatigue life. The stresslife sn or total life method is widely used for highcycle fatigue applicationshere the applied stress is within the elastic range of the material and the number of cycles to failure is large. This program was a followon effort to a program on improved high cycle fatigue hcf life prediction, usaf contract f3361596c5269, the results of which are documented in the final report on that prda program 1. Article very high cycle fatigue failure analysis and life prediction of crniw gear steel based on crack initiation and growth behaviors hailong deng 1, wei li 1, tatsuo sakai 2 and zhenduo sun 1. Therefore the fatigue strength at 106 cycles was 37% higher for forged steel than the cast iron. The existing very high cycle fatigue life model is not wellfit for high cycle fatigue model of fv520bi. Based on the fatigue experiments conducted by hocheng et al.
Correlations and engineering approximations have therefore become a necessary ingredient to the problems solution. Proposed high cycle multiaxial fatigue life prediction model critical plane and fatigue damage parameter as shown in figure 1, a thinwalled tube is subjected to sinusoidal outofphase tension and torsion loading. Common factors that have been attributed to low cycle fatigue lcf are high stress levels and a low number of cycles to failure. The program demonstrated the overall approach for developing methods that.
Research article a modified fatigue damage model for high. Indeed,thesocalledpalmgrenminerlinear damage rule ldr is widely applied owing to its intrinsic. Combined high and low cycle fatigue life prediction model. The highcycle fatigue life prediction procedure is shown in fig. High cycle fatigue life prediction for pbfree bga under random vibration loading. Dotfaaar106 determining the fatigue life of composite. Then the high cycle fatigue behavior of fv520bi affected by surface roughness is analyzed. Phasefield model for high cycle fatigue life prediction. The stress life sn or total life method is widely used for high cycle fatigue applicationshere the applied stress is within the elastic range of the material and the number of cycles to failure is large.
In principle, the case model parameters formalized, as a prior credibility using bayes theorem based on the available knowledge will make a more accurate fatigue life prediction. A new combined high and low cycle fatigue ccf life prediction model based on the damage mechanics theory is proposed in this paper. Based on the damage evolution equation of lemaitre and desmorat, a revised twoscale damage evolution equation for high cycle fatigue is presented according to the experimental data, in which factors such as the stress amplitude and mean stress are taken into account. Fatigue life in vacuum is considered to be longer than that in air, because there is no fatigue acceleration by oxidation in vacuum. These processes include creep, oxidation, phase instabilities and dynamic strain ageing dsa, acting either independently or synergistically influence fatigue behaviour, often lowering the fatigue life. Highcycle fatigue an overview sciencedirect topics.
Testing is conducted with constant strain amplitudes typically at 0. It is concluded that it is important to apply appropriate cycle counting and to account for interactions among high and low stresses. Proposed highcycle multiaxial fatigue life prediction model critical plane and fatigue damage parameter as shown in figure 1, a thinwalled tube is subjected to sinusoidal outofphase tension and torsion loading. Pdf a criterion for highcycle fatigue life and fatigue. Pdf highcycle fatigue life prediction for pbfree bga. In high cycle fatigue situations, materials performance is commonly characterized by an sn curve, or stress cycle curve, or fatigue curve, also known as a wohler curve. E1823 standard terminology relating to fatigue and fracture testing. Based on the exhaustion of the static toughness and dissipation of the plastic strain energy during fatigue failure, a new low cycle fatiguecreep life prediction model that is. Many studies have focused on this topic, but none have defined a good methodology for extracting the applied stress and predicting fatigue life accurately. Prediction of highcycle fatigue resistance is of great importance for structural design. Most metals with a body centered cubic crystal structure have a characteristic response to cyclic stresses.
The volumeaveraged stress was then obtained from harmonic analysis in the fea model. Highcycle fatigue life prediction for pbfree bga under. The crack growth rates depend on cycle times, strain amplitudes, mean stress, temperature and the environment 567. Bayesian framework for probabilistic low cycle fatigue. Verification tests are carried out to evaluate predicted results in combination with the experimental data. Together with the number of fatigue cycle results from. The program is a 5year, two part effort aimed at improving the high temperature crack initiation prediction technology for gas turbine hot section components. A numerical calculation of the fatigue lives of notched specimens is executed. Bayesian framework for probabilistic low cycle fatigue life. Lowcycle fatigue behavior of thick highstrength steel plates for pressure vessels. E739 statistical analysis of linear or linearized stress life sn and strain life n fatigue data. Fatigue test results in the aggressive environment left curve were an order of magnitude lower than the baseline fatigue life tested in air right curve. Experiments have shown that low cycle fatigue is also crack growth. Very high cycle fatigue failure analysis and life prediction.
The model parameters are fitted based on the material data and blade data respectively. E739 statistical analysis of linear or linearized stresslife sn and strainlife n fatigue data. Multiaxial highcycle fatigue life prediction model based. Highcycle fatigue is associated with low loads and long life. E1012 verification of specimen alignment under tensile loading e1049 cycle counting in fatigue analysis. This has been the approach used in the prediction of low cycle thermal fatigue in the past, and will ltkely remain as such for a number of years. Low cycle fatigue behavior of welded joints in high strength steels. Low cycle fatigue has two fundamental characteristics. Phasefield model for high cycle fatigue life prediction of brittle materials karlo seles,1, fadi aldakheel2, nenad gubeljak3, zdenko tonkovic1 and jurica soric1 1 faculty of mechanical engineering and naval architecture, university of zagreb, ivana lucica 5, 0 zagreb, croatia emails. Probabilistic high cycle fatigue life prediction for gas turbine engine blades. Low cycle fatiguecreep is the main reason for the failures of many engineering components under high temperature and cyclic loading. Growth of short cracks during high strain fatigue and thermal cycling.