Cumulative Damage Theory Research Articles

Fatigue Simulation of Railway Car Bogie Frame Based on Multi-body Dynamics and Finite Element Analysis

This paper proposes to combine multi-body dynamics and finite element method to study the fatigue strength and fatigue life of the bogie frame from the perspective of taking the vehicle as a whole. The analysis model established by the multi-body dynamics simulation software SIMPACK, the dangerous positions are determined from FEA software ANSYS, Based on the load-time history and Miner cumulative damage theory, the fatigue strength prediction is carried out using n-soft software, the study shows that the time-load history of each key position obtained by simulating working conditions can predict the life of components more accurately, this method can be applied to the initial stage of product design.

Fatigue Life Prediction for Semi-Closed Noise Barrier of High-Speed Railway under Wind Load

The fatigue state of the semi-closed noise barrier directly affects driving safety, and replacement after damage leads to train delays and increased operating costs. It is more eco-friendly and sustainable to predict the fatigue life of noise barriers to reinforce the structure in time. However, previous life prediction methods provide a limited reference in the design stage. In this study, a novel fatigue life prediction method for noise barriers was proposed. The computational fluid dynamics and finite element model of the semi-closed noise barrier were established and subjected to simulated natural wind and train aerodynamic impulse wind loads to calculate the stress time-history on the noise barrier. Based on the rain flow counting method and Miner linear cumulative fatigue damage theory, the fatigue life of noise barriers in three Chinese cities was predicted. The results show that the fatigue life of the noise barrier is closely related to the wind conditions and train operation modes. Targeted reinforcement for noise barriers in different fatigue states can save materials and reduce maintenance workload. Moreover, the influence of wind load on the noise barrier was summarized, and engineering suggestions on prolonging the fatigue life of noise barriers were put forward.

Low-speed impact damage analysis of aviation composite material structure

Although the carbon fiber reinforced composite material has high specific strength and stiffness, design-versatility, anti-corrosion and other excellent features, but the impact resistance of composite structures is poor. Therefore, the composite laminates low-speed damage analysis has important significance. Based on a three-dimensional analysis theory of cumulative damage, using the commercial finite element analysis software ABAQUS to establish laminates subjected to low velocity impact finite element model. according to the numerical results and the consistency of the test results, shows that the used model of the article is reasonable and accurate, and the numerical simulation method is verified to be feasible. Finally, through the numerical simulation of process of laminated plates low speed impact damage, the damage characteristics and damage mechanism of the laminates at different times are analyzed, and the forming reasons and expanding rules of the main damage forms of fiber damage and matrix damage are revealed.

Dynamic analysis of elliptical vibrating screen based on disc motor

ABSTRACT According to the requirements of the current drilling fluid vibrating screen for high efficiency, high reliability and low energy consumption, an elliptical vibrating screen based on disk motor is proposed. The dynamic analysis model of the vibrating screen of the three-excited motor is established, and the dynamic characteristics of the whole system and key structures are studied by multi-body dynamics and finite element method. The dynamic stress response characteristics of the rigid flexible coupling system of screen box are mainly analysed. Based on the deformation and stress of the flexible body damage node analysis results, through the fatigue cumulative damage theory and rain-flow counting method against casing load surface fatigue life prediction, verifying the reliability of fatigue life of screen box. The result shows that: Three Eccentric Rotors elliptical vibrating screen can achieve balanced elliptical vibration track, meeting the requirements of high stable amplitude vibration, and its natural frequency, structural strength and fatigue life all meet the engineering requirements, verifying the feasibility and effectiveness of the design scheme.

Cumulative Damage Modeling of Fuel Cell Membranes

The strongly varying humid environment under which fuel cell membranes operate introduces detrimental mechanical stresses that inflict damage to the membrane1. The damage incurred by the membrane during each humidity cycle when accumulated over time may lead the membrane to fatigue failure. The residual fatigue life of the membrane is determined here by using a cumulative-damage model2. A time-temperature-humidity dependent constitutive model and a multi-physics fuel cell finite element model are first developed to characterize the material properties and estimate the coupled mechano-hygral-thermal stress field in the membrane. Using this multi-level modeling approach, and with the aid of experimentally obtained fatigue data, fail-safe regions (see Figure) are identified for the case of accelerated stress test loading. For general loads simulating fuel cell operation, the distribution of stress-reversals is calculated for the load history using rain-flow counting algorithm. The regions of membrane that are more susceptible to fatigue damage are identified. It is also found that high amplitude stress cycles with low occurrence percentage are more detrimental than high occurrence low-amplitude cycles.This work was supported by Natural Sciences and Engineering Research Council of Canada, Simon Fraser University Community Trust Endowment Fund, Canada Research Chairs, Mitacs through the Mitacs Accelerate program, and Ballard Power Systems. 1 Borup, R., et al., Scientific aspects of polymer electrolyte fuel cell durability and degradation. Chemical Reviews, 2007. 107(10): p. 3904-3951. 2 Fatemi, A. and L. Yang, Cumulative fatigue damage and life prediction theories: a survey of the state of the art for homogeneous materials. International Journal of Fatigue, 1998. 20(1): p. 9-34. Figure 1

Impact Characteristics and Fatigue Life Analysis of Multi-Wire Recoil Spring for Guns

Recoil spring is a key part in automatic or semi-automatic weapons re-entry mechanism. Because the stranded wire helical spring (SWHS) has longer fatigue life than an ordinary single-wire cylindrically helical spring, it is often used as a recoil spring in various weapons. Due to the lack of in-depth research on the dynamic characteristics of the current multi-wire recoil spring in recoil and re-entry processes, the fatigue life analysis of the current multi-wire recoil spring usually only considers uniform loading and does not consider dynamic impact loads, which cannot meet modern design requirements. Therefore, this paper proposes a research method for fatigue life prediction analysis of multi-wire recoil spring. Firstly, based on the secondary development of UG, a three-wire recoil spring parameterized model for a gun is established. Secondly, ABAQUS is used to carry out a finite element analysis of its dynamic response characteristics under impact, and experimental verification is performed. Then, based on the stress-time history curve of the dangerous position obtained by finite element analysis, the rain flow counting method is used to obtain the fatigue stress spectrum of recoil spring. Finally, according to the Miner fatigue cumulative damage theory, the fatigue life prediction of the recoil spring based on the S-N curve of the material is compared with experimental results. The research results show that the recoil spring has obvious transient characteristics during the impact of the bolt carrier. The impact velocity is far greater than the propagation speed of the stress wave in the recoil spring, which easily causes the spring coils to squeeze each other. The maximum stress occurs at the fixed end of the spring. And the mean fatigue curve (50% survival rate) is used to predict the life of the recoil spring. The calculation result is 8.6% different from the experiment value, which proves that the method has certain reliability.

Fatigue investigation of tubing string in high-yield curved wells

In view of the fatigue failure of tubing string caused by fluid-induced vibration (FIV) in high-yield curved well, a nonlinear vibration model of tubing string is established using energy method and Hamilton principle, which considers the longitudinal/lateral coupling effect of tubing string and the nonlinear contact collision effect of tubing-casing and verified by a similar experiment of tubing vibration. The cumulative damage theory (Miner's Law) is used to establish the fatigue life prediction method of the tubing string in high-yield curved well combined with the stress response which was determined by the proposed vibration model and the S–N curve of the tubing material (13Cr-L80) which was measured by fatigue experiment. Based on that, the fatigue life of the tubing in two typical horizontal well and directional well was analyzed under different production rate (0.4–1.6 million square/day) and different tubing diameter (3.5-in and 4.5-in). The result shows that the most dangerous position of the tubing string appears between 3/4 position of the tubing string and the packer. The critical production rate of 4.5-in tubing string in horizontal well is 1.08 million square/day to satisfy the life requirements of gas reservoir tubing (20 years), and which is 0.45 million square/day in directional well. The fatigue life of 4.5-in tubing string is higher than that of 3.5-in tubing string in both horizontal and directional wells. The research results provide a theoretically sound guidance for designing and practically sound approach for effectively improving the service life of tubing string in high-yield curved wells.

Research on Reliability for Servo Turret Based on Vibration Transmission Path System with Stiffness Degradation Model

The stiffness degradation of the servo turret will inevitably lead to accuracy reduction of the cutter head and the tool change. Considering the degradation process of servo turret with stiffness, by introducing the stiffness cumulative damage theory into the vibration differential equation, combined with stochastic finite element method and reliability theory, the mathematical model of the reliability and reliability sensitivity for vibration transmission path system with random parameters was established. Taking a typical power servo turret for example, the reliability and the reliability sensitivity to each random parameter at the mean value with the excitation frequency and time were obtained. The results showed that the shift of the reliability and reliability sensitivity to random parameters with time was caused by the stiffness degradation, the peak value of reliability sensitivity fluctuated with time, and the peak value in the frequency domain at the initial time was not necessarily the maximum value in the time domain. The accuracy of the proposed method was further proved by the Monte Carlo method. Optimizing sensitive parameters could enhance the system stability and effectively prevent the resonance failure caused by the change of the resonance region.

Prediction of Fatigue Strength of Extra-Large Container Ships Based on Spectrum Analysis

Wang, J.T.; Jiang, B.C., and Guo, Y.L., 2020. Prediction of fatigue strength of extra-large container ships based on spectrum analysis. In: Al-Tarawneh, O. and Megahed, A. (eds.), Recent Developments of Port, Marine, and Ocean Engineering. Journal of Coastal Research, Special Issue No. 110, pp. 146–149. Coconut Creek (Florida), ISSN 0749-0208.With the rapid development of maritime transportation industry, container ships have quickly become the mainstream ship model due to their advantages of fast shipping speed, high handling efficiency, and low operating costs. At the same time, their large-opening structure has resulted in poor performance in bending strength, torsional strength and other mechanical properties. In order to ensure the structural safety performance of extra-large container ships, it is necessary to conduct an in-depth research on its fatigue damage and strength life. Based on the spectrum analysis, this paper takes the model 8601ETP extra-large container ship as an example, and adopts finite element modeling to obtain distribution range of the alternating stress; it also uses SN curve and linear cumulative damage theory to predict the fatigue damage and strength life of the container ship. The research results show that the fatigue damage of the extra-large container ship at full load is significantly more severe than that at no load; the degree of structural damage at the position of the keyhole is greater than that at the position of the hatch corner, so it is the hotspot for the fatigue damage analysis and strength check of extra-large container ships. This study provides certain theoretical reference and data support for improving the safety performance of large container ships, and it also enriches the theory of fatigue strength evaluation.

Fatigue life evaluation of spindle of rolling mill using ADINA structure and WINLIFE

The fatigue life prediction method using numerical analysis is the latest evaluation technology to predict the fatigue life using the stress data obtained from the structural analysis in order to reduce the evaluation time and cost. A rolling mill is a machine that produces a coil by rolling the material by a roller and the spindle of the rolling mill device serves to transmit the power to the rollers by periodically rotating by the motor. These spindles consist of universal joints, shafts and bearings to deliver power to the rollers. The spindle of the rolling mill is always exposed to the environment subjected to the fatigue load due to the rotation moment by the periodic rotation and there is possibility of the breakage accident due to this. It is very important to prevent breakage by predicting the fatigue life of the spindle in a dynamic operating environment. Therefore, in this study, dynamic stress analysis is performed considering the actual rotating environment conditions using ADINA. Based on the results of stress analysis, we want to predict fatigue life considering dynamic operating environment using WINLIFE that is used for the evaluation of the fatigue life of single shafts, multi-shafts, and gear bearings. Fatigue life analysis of the spindle of the rolling mill using linear cumulative damage theory using S-N curve and equivalent stress was performed in order to evaluate the fatigue life. Stress-life fatigue theory is a method of calculating the lifetime by the minimum input showing the fatigue characteristics of the material.

Analysis of pipeline fatigue performance under random vibration load

As one of the most important equipments in power plant, the mechanical properties of steam pipe were analysed in this paper. Random vibration theory and Miner linear cumulative damage theory as well as frequency-domain fatigue analysis method were adopted, modal analysis and fatigue performance analysis of the in-service steam pipe were carried out with ANSYS, calculated first ten natural frequencies and cumulative damage under random excitation use Steinberg three-interval method. Results show that no fatigue failure will occur under this excitation load, the random vibration frequency-domain fatigue analysis method can effectively evaluate the fatigue performance of steam pipe, and provide a reference for the pipeline random vibration fatigue analysis.

Prediction and evaluation of fatigue life for mechanical components considering anelasticity‐based load spectrum

AbstractTo accurately predict the degraded fatigue life of components under random loads, anelasticity effect of metal on life estimation needs to be explored. Weighting coefficient and dynamic elastic modulus are introduced to modify the calculation process of the model. By establishing an equal‐amplitude fatigue median surface and applying Miner linear fatigue cumulative damage theory, a fatigue life prediction model of the component under random loads is proposed. The model can be used to calculate the degraded fatigue life of components, which provides a theoretical basis for life estimation under random load spectrum. The two‐dimensional load spectrum is compared with the unprocessed two‐dimensional load spectrum and the one‐dimensional program spectrum in life prediction results. With the comparison of the target life and simulation life and the data calculated by the model of the automobile front stabilizer bar, it is concluded that the data obtained by the modified model are more reasonable and accurate.

Cumulative fatigue damage in thin aluminum films evaluated non-destructively with lasers via zero-group-velocity Lamb modes

In this paper, a non-contact non-destructive evaluation of cumulative fatigue damage in 75μm-thick aluminum plates is conducted by using the first symmetric zero-group-velocity Lamb mode and taking benefit of its local and long-lasting resonance feature. The tested aluminum sheets are subjected to fatigue loading, in a two sides clamped compression configuration inducing buckling. For understanding the experimental observations, we propose and establish an empirically-inspired theoretical modeling based on the cumulative damage theory, completed with a finite element simulation, for comparison with the experimental measurements. The observed phenomena along fatigue cycles show the potential for the prediction of the fatigue lifetime and the quantitative assessment of different stages of the fatigue damage in solid plate structures. Good agreement is found between the proposed theory/simulation and the experiment on zero-group-velocity resonance frequency. The quality factor of zero-group-velocity resonance is also experimentally studied and compared with numerical calculations, a disagreement is observed after ∼30% of fatigue lifetime. This point elucidates the start time of the change of mechanical properties during the early fatigue stage and is identified as a potential path for the improvement of the proposed empirical model in the future.

An experimental investigation of static and fatigue behaviour of GFRP sandwich beams with a web reinforced wood core

Three-point static and fatigue bending experiments were performed on 51 composite sandwich beams with glass fibre reinforced polymer (GFRP) face sheets and paulownia wood cores. Specimens with no lattice, one lattice and two lattices were prepared, and the fatigue bending failure mode, fatigue life distribution and stiffness degradation model of the sandwich beams were obtained. The results show that the specimens with no lattice exhibit two brittle failure modes, i.e., interface debonding and core shearing. The failure modes of the specimens with one lattice are local buckling and crushing, while the specimens with two lattice webs only exhibit tensile failure of the bottom face sheet. Moreover, the specimens with webs exhibit ductile failure characteristics. Based on the Weibull model, the Weibull distribution equations of each specimen under different survival rates were established, and the engineering fatigue curve was drawn. Furthermore, the secant stiffness curve of the specimens with webs was established based on the fatigue cumulative damage theory, and the fatigue lives of three specimens were predicted.

Fatigue Life Analysis of Longitudinal Welding Seam for Wind Turbine Tower

Tower is an important fundamental component of large-scale wind turbines. The fatigue performance of the tower welded part directly affects the running safety and reliability of wind turbines. A fatigue life predicting method for the longitudinal welding seam of the tower is proposed in this paper. Under the precondition of satisfying the limit strength, the time series stress of each working condition is obtained by DIN18800-4 section stress calculation. Combined with the rain-flow counting method and the Miner linear cumulative damage theory, the fatigue life of the tower longitudinal weld is predicted. The results show that the tower structure meets the design requirement, and the feasibility and effectiveness of the method are verified.

Fatigue Life Prediction for Flange Connecting Bolts of Wind Turbine Tower

Flange joint part is the weak link of wind turbine tower. In view of the special structure, complex stress and easy failure of the connecting bolt of the wind turbine tower flange, the relationship between the external load of the tower section and the internal stress of the bolt is established by the finite element method, and the time series internal stress of the bolt is calculated by the Schmidt-Neuper algorithm. The S-N curve which is suitable for the connecting bolt material of the tower flange is selected by the GL2010 specification. On the basis of Miner’s fatigue cumulative damage theory and rain flow counting method, the fatigue strength of the whole ring bolt is roughly calculated, and the most dangerous part is determined. The axial symmetry model of screw connection is used for accurately calculating the fatigue cumulative damage of the bolt at the dangerous part. The results show that the fatigue life of the bolts in the most dangerous position can meet the requirements, the engineering algorithm has advantages in determining the dangerous part of the whole ring bolt, and the finite element method has high accuracy in predicting the fatigue life of the bolts in the dangerous part. The proposed method is feasible and effective in predicting the fatigue life of the flange joint bolts of the tower.

Improvement in fatigue strength of 41Cr4 steel through slide diamond burnishing

Slide burnishing (SB) is a static mechanical surface treatment based on the severe plastic deformation of the surface for which the contact between the deforming element and the surface being treated is sliding friction. SB improves the surface integrity of metal structural and machine components dramatically. This paper is devoted to improving the fatigue strength of 41Cr4 steel hourglass-shaped specimens subjected to SB with a spherical-ended deforming diamond via different combinations of basic governing parameters. Since the residual compressive stresses introduced play a significant role for the fatigue behavior of the burnished components, a comprehensive parametric study of the SB process was conducted using fully coupled thermal-stress finite element (FE) simulations. The FE model’s adequacy was proven via comparison of the FE results for the residual stresses with X-ray diffraction measurements. The results obtained show that the diamond radius and the burnishing force have the strongest effects on the residual stresses, which, in turn, have a significant influence on the fatigue strength, respectively, fatigue life. An extensive experimental investigation of the effect of the selected SB basic parameters on the fatigue limit of the slide burnished specimens was carried out using Locatti’s method. The latter is based on the Palmgren–Miner linear damage hypothesis, which is a particular case of a general cumulative damage theory. A planned experiment was carried out, with the governing factors changed among four levels. Regression analysis of the experimental results was carried out, and a model for predicting the fatigue limit was obtained. Based on the model obtained, a one-purpose optimization was carried out using a genetic algorithm. By means of the optimal basic parameters, the fatigue limit of the processed specimens was increased by 22.7%—from 440 to 540 MPa. The fatigue life increased more than 100 times over after SB with the optimal basic parameters.

Crack growth life estimation for No. 17 coupler knuckle in China Datong-Qinhuangdao railway freight trains

In order to predict the fatigue life of couplers for heavy haul railway freight trains of the Datong-Qinhuangdao Railway in China, a model for calculating the crack initiation life of coupler knuckle is established based on the stress-strain relationship of coupler knuckle material and the theory of cumulative damage. Considering the local plastic effect of coupler structure, the stress dangerous part of coupler knuckle is defined by adopting the steady state method in the local stress-strain method. Based on the longitudinal coupler load spectrum of the 20,000-ton freight train under study and considering the randomness of coupler position, the mixed coupler load spectrum is obtained for the first time. The fatigue life of coupler knuckle of a particular heavy haul railway freight train is calculated. The life of coupler knuckle calculated by the method presented in this paper is consistent with the actual repair cycle of coupler, which can effectively minimize the impact of coupler crack fault on the train operation safety.

Analysis of Safe Span Length and Fatigue Life of Submarine Pipelines

Owing to the complex environmental conditions, suspension could induce complicated forces on submarine pipelines and even cause vortex-induced vibration, resulting in fatigue damage of pipelines. Through aiming at the 28-inch submarine pipeline in the East China Sea, the pipeline was segmented according to the similarity, considering the factors of pipe assembly, typhoon, current, wave and seabed topography. The effects of span length on natural frequency in each section of submarine pipeline were analyzed by finite element model. The maximum safe span length allowed by each pipeline section was verified by fatigue cumulative damage theory, and the fatigue life of each pipeline section were predicted. The results showed that each order natural frequency of the pipeline decreased with the increase of span length. The calculated results of empirical formulas were much smaller than those of the FEM analysis. The increase of the gap between the suspended pipeline and the seabed was beneficial to enhance the fatigue life of the suspended pipeline.

Analysis of Dynamic Response and Fatigue Life of Masonry Pagoda under the Influence of Train Vibration

Taking Liangxiang Pagoda built in Liao Dynasty in Beijing as the research object, the vibration responses of the pagoda in the east‐west direction and south‐north direction under the action of trains on the Beijing–Guangzhou Railway Line and microseism were tested. On this basis, a numerical model was established by using ANSYS to further calculate the dynamic response of the pagoda, and the safety and integrity of the pagoda were evaluated based on existing standards. Cumulative fatigue damage theory was introduced to predict the remaining fatigue life of Liangxiang Pagoda. The following conclusions have been drawn: in the two directions mentioned above, the natural vibration frequencies of the pagoda of the first three orders are similar; the 1st‐order vibration modes in the plane are bending, and the vibration modes of the 2nd and 3rd orders are shear‐bending; under the action of trains, the peak vibration value of Liangxiang Pagoda at the position that bears the maximum load is 0.053 mm/s, which has a little impact on the safety and integrity of the pagoda; under the combined action of gravity and trains, the remaining fatigue life of Liangxiang Pagoda is 5.26 × 107 times. The research method used in this paper can provide data and scientific support for the protection of historical buildings, as well as the basis for the follow‐up research of the studied ancient pagoda.