Showing papers on "Vibration fatigue published in 2022"
TL;DR: Based on the theory of crack initiation and propagation, the authors proposes a life prediction algorithm considering residual stress; carries out a bending vibration fatigue experiment and simulation fatigue life analysis of aero-engine blade grinding with abrasive belt; compares the results of experiments and simulations and proposes a residual stress equivalent calibration method.
57 citations
TL;DR: Based on the theory of crack initiation and propagation, the authors proposes a life prediction algorithm considering residual stress; carries out a bending vibration fatigue experiment and simulation fatigue life analysis of aero-engine blade grinding with abrasive belt; compares the results of experiments and simulations and proposes a residual stress equivalent calibration method.
57 citations
TL;DR: In this paper, a non-proportionality correlation function is proposed to interrelate the resulting power spectrum density (PSD) of normal and shear traction stresses and their cross-PSD for establishing an effective stress parameter.
28 citations
TL;DR: In this article , a new spectrum synthesis method to obtain the actual environmental vibration profiles for railway equipment is proposed. But the results show that the synthesized PSD can reflect the characteristics of environmental vibrations, including the additional excitation of rail wear, and compared with the fatigue results of the tests and simulations conducted under the standard spectrum, the predicted results under the synthesised spectrum were determined to be most similar to real-world scenarios, while the use of the standardized spectrum exhibited infinite life.
13 citations
TL;DR: In this paper , a nonlinear model is proposed in light of the theory of isodamage curves, to assess the cumulative fatigue damage under multistage loading, and a stress function for the fatigue life exponent is derived with the aid of the S-N curve.
Abstract: A nonlinear model is proposed in light of the theory of isodamage curves, to assess the cumulative fatigue damage under multistage loading. The isodamage curves were developed through the theory of the S-N fatigue damage envelope, proposed by Pavlou. The adopted functional form of the fatigue damage is a commonly accepted general form. In the present work, a stress function for the fatigue life exponent is derived with the aid of the S-N curve only. In the proposed nonlinear model, no adjusting parameters are necessary for fatigue damage estimation. The fatigue life prediction of the derived model is compared with experimental results of various alloys and existing models. The comparison is made for C35, C45, Al-2024-T42, 15HM, A336 GR 5, and A387 GR22 for two-stage loading high-low and low-high, and Al 6082-T6 for multistage loading.
11 citations
TL;DR: In this paper , three spectral methods for the estimation of fatigue life were used to determine the fatigue life of a 3D printed Y-shaped specimen realized in polylactic acid subjected to random loads with the aim of determining their adaptability also for this kind of materials.
Abstract: Additive manufactured structures are replacing the corresponding ones realized with classical manufacturing technique. As for metallic structures, 3D printed components are generally subjected to dynamic loading conditions which can lead to fatigue failure. In this context, it is useful, and sometimes mandatory, to determine the fatigue life of such components through numerical simulation. The methods currently available in literature for the estimation of fatigue life were originally developed for metallic structures and, therefore, it is now necessary to verify their applicability also for components fabricated with different materials. To this end, in the current activity three of the most used spectral methods for the estimation of fatigue life were used to determine the fatigue life of a 3D printed Y-shaped specimen realized in polylactic acid subjected to random loads with the aim of determining their adaptability also for this kind of materials. To certify the accuracy of the numerical prediction, a set of experimental tests were conducted in order to obtain the real fatigue life of the component and to compare the experimental results with those numerically obtained. The obtained outcomes showed there is an excellent match between the numerical and the experimental data, thus certifying the possibility of using the investigated spectral methods to predict the fatigue life of additive manufactured components.
11 citations
TL;DR: In this paper, the authors identified fatigue cracks in a steel joint under vibration by nonlinear guided waves based on second harmonic generation, where piezoelectric transducers were used to excite S1 Lamb wave mode in experiment and the nonlinear ultrasonic testing was performed at different crack lengths.
10 citations
TL;DR: In this article , the authors identified fatigue cracks in a steel joint under vibration by nonlinear guided waves based on second harmonic generation and used the finite element method to verify the experimental results and they were in good consistence.
10 citations
TL;DR: In this paper , a fatigue life model based on the unified mechanics theory is introduced to predict the very high cycle fatigue life of metals, without the traditional empirical curve fitting a fatigue damage evolution function.
9 citations
TL;DR: In this article , a finite element model with the initial crack based on linear elastic fracture mechanics (LEFM) was established, and the parameter analysis of the stress intensity factors (SIFs) of the studs and cracks with different geometric sizes was performed.
Abstract: To investigate the fatigue performance of the stud connectors of steel-concrete structures, fatigue crack propagation analysis and fatigue life calculation were carried out. Firstly, the finite element model with the initial crack based on linear elastic fracture mechanics (LEFM) was established, and the parameter analysis of the stress intensity factors (SIFs) of the studs and cracks with different geometric sizes was performed. Then, the propagation with mixed-type fatigue crack and I-type fatigue crack of the stud were calculated, and the variation of effective SIFs with the fatigue crack depth was analyzed. Finally, the flow chart of stud fatigue life evaluation which considers crack initiation and stable propagation was presented, and the short stud of steel-UHPC composite structures was taken as an example and verified. The calculation results show that the fatigue crack propagation type and the initial crack have an obvious influence on the fatigue life of the stud. It has acceptable accuracy that the fatigue life of short stud in UHPC simulated by considering the crack initiation. The critical damage parameters are greatly affected by the fatigue stress amplitude, and the initiation life of fatigue crack can account for more than 90% of the total fatigue life. This paper can provide a reference for evaluating the fatigue performance of studs in steel-concrete composite structures. Accurate evaluation of the fatigue life of stud connectors conforms to the concept of sustainable development.
9 citations
TL;DR: In this paper, a fatigue life model based on the unified mechanics theory is introduced to predict the very high cycle fatigue life of metals, without the need for the traditional empirical curve fitting a fatigue damage evolution function.
TL;DR: An assessment of fatigue-based reliability in measuring failure random vibration loadings due to unexpected loads under various road conditions shows that a coil spring could withstand the uneven road surface without failing prematurely, and can evaluate the hazards of rate-reliability, based on predictions of fatigue life data on component durability.
TL;DR: In this paper , a new model for frequency-domain fatigue life prediction based on modified narrowband distribution model was proposed, which takes the second-order spectral width parameter of vibration signal as the weight coefficient, and the life prediction results are more accurate and less dispersive.
TL;DR: In this article , the authors present an assessment of fatigue-based reliability in measuring failure random vibration loadings due to unexpected loads under various road conditions, where acceleration signals were measured during a road test held on rural and highway road surfaces.
TL;DR: In this paper , the uncertainties in fatigue loads, damage and crack growth to be incorporated in reliability assessments are considered, and special attention is paid to the associated governing factors and their uncertainties as they are required for fatigue reliability analyses.
TL;DR: In this article , the authors proposed a new FCG model containing a material-independent equivalent factor N through energy principle during crack growth, which could theoretically illustrate the effect of stress ratio on the FCG rate of metallic materials.
TL;DR: In this article, a mathematical model of the tube bundles subjected to two-phase flow and the clearance restriction was developed, considering the effects of the turbulence random forces and the fluidelastic forces.
TL;DR: In this article, a mathematical model describing the transmission law of the kurtosis between the decomposed signal of excitation and response signal is established, and it is possible to quantitatively estimate the structural response according to this relationship, which lays the foundation for accurately predicting the vibration fatigue life of structures under nonstationary and non-Gaussian random excitations.
TL;DR: In this article , the average phase difference is characterized as the ratio of the number of shear strain cycles to normal strain cycles, and the new non-proportional additional hardening factor is proposed.
Abstract: PurposeEngineering components/structures are usually subjected to complex and variable loads, which result in random multiaxial stress/strain states. However, fatigue analysis methods under constant loads cannot be directly applied to fatigue life prediction analysis under random loads. Therefore, the purpose of this study is how to effectively evaluate fatigue life under multiaxial random loading.Design/methodology/approachFirst, the average phase difference is characterized as the ratio of the number of shear strain cycles to the number of normal strain cycles, and the new non-proportional additional hardening factor is proposed. Then, the determined random typical load spectrum is processed into a simple variable amplitude load spectrum, and the damage in each plane is calculated according to the multiaxial fatigue life prediction model and Miner theory. Meanwhile, the cumulative damage can be calculated separately by projection method. Finally, the maximum projected cumulative damage plane is defined as the critical plane of multiaxial random fatigue.FindingsThe fatigue life prediction capability of the method is verified based on test data of TC4 titanium alloy under random multiaxial loading. Most of the predicting results are within double scatter bands.Originality/valueThe objective of this study is to provide a reference for the determination of critical plane and non-proportional additional hardening factor under multiaxial random loading, and to promote the development of multiaxial fatigue from experimental studies to practical engineering applications.
TL;DR: In this paper , a new multiaxial fatigue life prediction model is developed by considering the effects of both stress gradient effect (SGE) and notch size effect (NSE) on the fatigue performance of engineering components.
TL;DR: In this article , an adaptive modeling of vibrations and structural fatigue in a rotating system with a propagating crack is proposed. But, it is not shown that assuming constant and pre-defined length for these steps can significantly affect the accuracy of the model leading to inaccurate lifetime prediction and poor prognostics in general.
TL;DR: In this paper , a novel fatigue-life prediction methodology combining a subcycle fatigue crack growth (FCG) analysis and equivalent initial flaw size (EIFS) concept is proposed for life assessment under random loadings.
TL;DR: In this article , the authors proposed a new methodology to assess the fatigue life of overhead conductors, which relies on a global stress analysis of a multistranded conductor using a 3D finite element (FE) beam-to-beam contact model and a local fatigue damage analysis of the wires.
TL;DR: In this article , the QTM approach was applied to predict the fatigue life of materials and welded joints under variable amplitude loading in both low and high cycle fatigue regimes, and the results showed that the approach was able to take into account the loading sequence effect.
Abstract: Quantitative thermographic methodology (QTM), which takes energy dissipation as a fatigue indicator, has been successfully applied to predict the fatigue life of materials and welded joints under constant amplitude loading. This study advances the QTM approach for predicting the fatigue life under variable amplitude loading in both low and high cycle fatigue regimes. Experimental data, obtained by fatigue tests under variable amplitude loading, were used in order to apply the developed QTM approach and to demonstrate that it is able to take into account the loading sequence effect. Good predictions of the fatigue life were achieved.
TL;DR: In this paper , the effect of stress reversals on the fatigue evaluation of a conventional OSD and a lightweight composite deck was investigated from infinite-life and finite-life perspectives based on finite element analysis.
TL;DR: In this article , the power spectral densities (PSD) of the vibration signals were obtained and then analyzed using three PSD cycle counting models, including the Lalanne, Dirlik and Narrowband methods.
TL;DR: In this paper , the effect of average strain on the low-cycle fatigue life of materials under different strain cycle ratios was discussed based on the framework of damage mechanics and its irreversible thermodynamics.
Abstract: To address the difficult problems in the study of the effect of average strain on fatigue life under low-cycle fatigue loads, the effect of average strain on the low-cycle fatigue life of materials under different strain cycle ratios was discussed based on the framework of damage mechanics and its irreversible thermodynamics. By introducing the Ramberg-Osgood cyclic constitutive equation, a new low-cycle fatigue life prediction method based on the intrinsic damage dissipation theory considering average strain was proposed, which revealed the correlation between low-cycle fatigue strain life , material properties, and average strain. Through the analysis of the low-cycle fatigue test data of five different metal materials, the model parameters of the corresponding materials were obtained. The calculation results indicate that the proposed life prediction method is in good agreement with the test, and a reasonable characterization of the low-cycle fatigue life under the influence of average strain is realized. Comparing calculations with three typical low-cycle fatigue life prediction models, the new method is within two times the error band, and the prediction effect is significantly better than the existing models, which is more suitable for low-cycle fatigue life prediction. The low-cycle fatigue life prediction of different cyclic strain ratios based on the critical region intrinsic damage dissipation power method provides a new idea for the research of low-cycle fatigue life prediction of metallic materials.
TL;DR: In this article , a new multiaxial fatigue life prediction method was developed taking into account stress gradient effects and additional hardening effects, and the estimated lives using the proposed method and the equivalent stress method were compared with the test life.
TL;DR: A Simulation-Driven Dynamic Test (SDDT) framework that deconstructs vibration fatigue experiments into step-wise steady-state analyses is suggested that will enable investigating the failure mode mixity of the underlying failure criterion, and simulating the surface temperature during the delamination growth under vibration conditions.
TL;DR: In this paper , the authors proposed a novel gear bending fatigue model incorporating gradient characteristics of hardness and residual stress based on the continuum damage theory to evaluate the bending fatigue behavior of case hardened wind turbine gear.