Reliability Assessment of Fatigue Life of Hangers in Large-Span Suspension Bridges

2011 ◽  
Vol 147 ◽  
pp. 149-152
Author(s):  
Yong Zeng ◽  
Hong Mei Tan
Keyword(s):  
Time History ◽  
Public Confidence ◽  
Suspension Bridges ◽  
Fatigue Reliability ◽  
Load Spectrum ◽  
Accurate Analysis ◽  
Vehicle Load ◽  
History Of ◽  
Vehicle Loads ◽  
Main Cables

Hangers are very important components for suspension bridges, which link main cables and stiffening girders. When in service, hangers are much vulnerable to fatigue loads due to kinds of traffic flows, which may reduce the remaining life of the hangers and increase the risk of losing public confidence in cable supported bridges. In order to quantify the reliability of hangers under vehicle loads, fatigue reliability formula of hangers is proposed in this paper. Based on the accurate analysis of vehicle load spectrum, the time history of hangers is simulated and maintenance strategy is proposed.

Diagnose Method Based on Spectral Analysis of Measured Parameters

2014 ◽  
Vol 1036 ◽  
pp. 535-540 ◽  
Author(s):  
Radu Vilău ◽  
Marin Marinescu ◽  
Octavian Alexa ◽  
Marian Truta ◽  
Valentin Vinturis
Keyword(s):  
Frequency Analysis ◽  
Fourier Transforms ◽  
Power Spectra ◽  
Time History ◽  
Point Of View ◽  
Mechanical Parameter ◽  
Accurate Analysis ◽  
Frequency Spectra ◽  
Time Frequency ◽  
History Of

The paper presents a possible method to diagnose a mechanical fault of an automotive system. Starting from the point of view that every fault of a mechanical system should introduce an abnormal component within the signal that describes the time history of a mechanical parameter we tried to find a way to reveal it.We were performing some tests involving a military vehicle with respect to the performances of its braking system. The tests were aiming at identifying a way to bring up-to-date the old weapon system from the braking systems point of view. During these tests we observed some anomalies concerning the pressure evolution within the braking cylinders of the vehicle. Some unusual but also systematic noises occurred. As a main issue at this point, the source of the noise should have been identified and filtered if necessary. We had to decide whether the noisy component of the signal is just a noise that should be removed by filtering the signal or it is a physical component of the mechanical parameter itself (not noise but a useful information).These procedures take time and they also request accurate knowledge as well as fine expertise in automotive testing. Since our Dept. has a long and rich practice in this respect, we assumed to processing data and give them a thorough interpretation. So, the first thing we did was to perform a frequency analysis, using classical methods. Usually, a simple frequency analysis cant provide information about a time variation of the frequency spectra due to the Fourier Transforms behavior, since it freezes the signal in time. A much more accurate analysis is the time-frequency analysis. However, observing both the amplitude and power spectra can lead to a useful conclusion. We concluded that the noise we met within the signal is due to the brake drums loss of circular shape (they turned into an oval, the process being known as ovalization). Hence, we cant talk about a noise as it is usually defined.

Statistical Analysis of Loader’s Drive Axle Housing Random Load Spectrum

2011 ◽  
Vol 338 ◽  
pp. 456-459 ◽  
Author(s):  
Bu Zheng Wen ◽  
Jian Min Li ◽  
Zhong Tao Pei ◽  
Sheng Yu ◽  
Cuan Yang Sun ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Weibull Distribution ◽  
Fatigue Reliability ◽  
Load Spectrum ◽  
Distribution Fitting ◽  
Random Load ◽  
Structural Fatigue ◽  
History Of ◽  
Drive Axle ◽  
Drive Axle Housing

Statistical analysis of load spectrum is an important part on structural fatigue life and reliability research, it is generally considered that axle’s load spectrum follows Weibull distribution. This paper tested ZL50 loader’s loading history of different working conditions , and obtained the corresponding load spectrum by rain-flow counting method, then analyzed three distributions’ (normal distribution, lognormal distribution, Weibull distribution) fitting degree of load spectrum and effect on the fatigue reliability. Results show that the highest fitting degree of distribution function should be used to fit load spectrum, which can reduce the error in structural fatigue reliability prediction.

Analysis of the dynamic response and fatigue reliability of a full-scale carbody of a high-speed train

2018 ◽  
Vol 232 (7) ◽  
pp. 2006-2023 ◽  
Author(s):  
Yaohui Lu ◽  
Linyuan Dang ◽  
Xing Zhang ◽  
Zhen Feng ◽  
Jing Zeng ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Probability Distribution ◽  
Failure Rate ◽  
Surrogate Model ◽  
High Speed ◽  
Time History ◽  
Strength Degradation ◽  
High Speed Train ◽  
Fatigue Reliability ◽  
History Of

For a vehicle operating under different line conditions, coupled with track irregularity and many other factors, the carbody is subjected to extremely complex random loads, and the load mainly exists in the form of an alternating load; therefore, the primary type of failure is fatigue failure. With the continuous improvement in train speed, lightweight designs of carbody structures and the application of high-strength aluminium alloy, the safety and reliability of a carbody require more attention. An investigation of the dynamic fatigue reliability of a full-scale carbody of a high-speed train under random load conditions is carried out. A dynamics model of the vehicle system has been established for acquiring the time history of forces acting on the carbody by each air spring (hereinafter referred to as ‘the load–time history’). A surrogate model (a simple model instead of a complex carbody model) of the carbody is established based on the Box–Behnken matrix design and the polynomial fitting method; then, the load–time history is transformed to the stress–time history of the points of concern, and the results are compared with the results of the transient analysis, which verify the accuracy and effectiveness of the surrogate model. Then, a stress block spectrum is obtained by rain flow counting, and the stress probability distribution is determined. Combined with the probability distribution of fatigue strength, a dynamic stress–strength interference model (the area of interference between strength and stress in the model changes over time) is established. The failure rate and dynamic reliability of the points of concern for two cases are analysed: without considering the strength degradation and considering the strength degradation. The results show that without considering the strength degradation during service, with increased service mileage, the fatigue strength reliability of the points of concern decreases continuously, and the corresponding failure rate of the points of concern decreases with time and reaches a steady value, which has the characteristics of the first two stages of the bathtub curve. By considering the strength degradation during service, the reliability of the points of concern decreases gradually, and the corresponding failure rate of the points of concern decreases and then increases, with all the features of the bathtub curve. In addition, compared with the base metal region, the fatigue resistance of the welded structure decreases due to welding. Under the same service conditions, the reliability of the welded region is relatively low, and fatigue failure is more likely to occur.

Analysis on Load Spectrum of Bogie Frame for High-Speed EMU

2014 ◽  
Vol 633-634 ◽  
pp. 1166-1173
Author(s):  
Yu Guang Wang ◽  
Da Fu Zhang
Keyword(s):  
Fatigue Life ◽  
Dynamic Model ◽  
High Speed ◽  
Estimation Method ◽  
Time History ◽  
Load Spectrum ◽  
Safe Operation ◽  
Bogie Frame ◽  
Key Factor ◽  
History Of

The load spectrum, on which there is not a thorough research, is the key factor of the safe operation of EMU. A dynamic model of some high-speed EMU is established and the load time history of main load on frame is obtained through simulation and analysis based on the Beijing-Tianjin route. The load spectrum for main load is calculated by rain-flow counting, the crossing contrast of load spectrum in basic and fault conditions is proceeded as well, the extent of impact of all kinds of fault conditions to bogie main load is analyzed and a brief introduction of estimation method of the frame fatigue life is put forward in this paper.

scholarly journals Study on Suspender’s Fatigue Performance of Half-through CFST Arch Bridge due to Vehicular Loads

2012 ◽  
Vol 5 ◽  
pp. 189-194 ◽  
Author(s):  
Hang Sun ◽  
Jun Ma ◽  
Bo Yu
Keyword(s):  
Damage Model ◽  
Fatigue Performance ◽  
Traffic Load ◽  
Fatigue Reliability ◽  
Analysis Model ◽  
Load Spectrum ◽  
Stress History ◽  
Arch Bridge ◽  
Flow Investigation ◽  
History Of

Due to the repeated action of vehicular loads, fatigue failure of suspenders of half-through arch bridge is main failure type. Usually the stress history of suspender is relevant with the vehicle load, dynamic property of structure and so on. In this paper, the traffic load spectrum investigation of Ha-Tong road is constructed through a 24-hour traffic flow investigation; And the space FEM established to get the stress response；Assume the fatigue performance of suspender as stochastic variable, the stress history of suspender is a stochastic process which changes with time, fatigue reliability analysis model is suggested based on accumulated damage model；Taking YIlan bridge as an example, the study on the effect of suspenders’ length and deck type are carried out. The research method and results can be referenced while designing or evaluating the same bridge type.

Fatigue Damage of a Cutter Used for Cutting Cashew Nut under Random Load

2015 ◽  
Vol 743 ◽  
pp. 49-54
Author(s):  
Y.F. Fu ◽  
J. Gong ◽  
D.M. Zhu ◽  
Y.J. Liu ◽  
Hui Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fatigue Damage ◽  
Equivalent Stress ◽  
Time History ◽  
Post Processing ◽  
Load Spectrum ◽  
Random Load ◽  
Cashew Nut ◽  
History Of ◽  
Processing Software

To study the fatigue damage of a cutter used for cutting cashew nut, the integrated<br />simulation platform is established with Hypermesh, LS-Dyna, LS-PrePost, and nCode GlyphWorks.<br />The simulation model is established by Hypermesh. LS-Dyna is used to calculate the k file.<br />LS-PrePost is used as the post-processing software. The rain-flow counting, load superposition and<br />extrapolation are executed using Rainflow module in nCode GlyphWorks. The analysis of the<br />fatigue damage of the cutter is executed using Stress Life module in nCode GlyphWorks. The<br />equivalent stress time history of different elements in the upper and lower cutters, rain-flow<br />counting histogram after load spectrum superposition, rain-flow counting histograms after load<br />spectrum extrapolation, and damage histogram of the cutter are obtained. The results show that the<br />cutter has excellent mechanical properties, and the minimum fatigue life of the cutter is about 495<br />days, which is a conservative solution.

Analysis of C80B Wagon’s Load-Stress Transfer Relation

2011 ◽  
Vol 148-149 ◽  
pp. 331-335 ◽  
Author(s):  
Yu Qing Yuan ◽  
Qiang Li ◽  
Kun Ran
Keyword(s):  
Great Influence ◽  
Time History ◽  
Stress Transfer ◽  
The Body ◽  
Load Spectrum ◽  
Element Analysis ◽  
Car Body ◽  
History Of The Body ◽  
Stress Spectrum ◽  
History Of

In this paper, C80B car body is the research object to study the load-stress transfer relationship that has great influence on the car body structure. First of all, through the test data of line DaTong to Qin Huangdao, the load-time history of C80B car body’s load on center plate, load on draw gear, roll load and torsional load have been obtained, as well as the stress-time history of the body fatigue key parts have been obtained. And the load spectrum and stress spectrum have been made up. Then the finite element analysis of the car body is made. The load-stress transfer coefficient of fatigue key parts on car body could be obtained. Last the load and stress transfer relationship in detail considering the measured data has been analyzed.

scholarly journals The problem of evaluating the expiration of the service life of the supporting structure of secondhand cranes

2019 ◽  
Vol 49 (1) ◽  
pp. 37-45
Author(s):  
Włodzimierz Rosochacki
Keyword(s):  
Service Life ◽  
Production Capacity ◽  
Secondary Market ◽  
Triangular Distribution ◽  
Load Spectrum ◽  
Accurate Analysis ◽  
Supporting Structure ◽  
History Of ◽  
The Right ◽  
Gantry Cranes

The right to safety of purchased goods is one of the most important consumer rights. Therefore, an accurate analysis of safety of machinery and equipment purchased on the secondary market is an extremely important issue. One of its elements should be the assessment of the degree of service live usage. In the case of cranes, the subject of such an assessment covers both the supporting structure of the device and its mechanisms and installations. Information on evaluation of the service life expiration of the secondhand cranes may be necessary and support the decision-making process associated with the purchase of the device. The paper deals with the problem of evaluating the expiration of the service life of the supporting structure of cranes coming from the secondhand market. The result of such evaluation makes it possible to determine whether the production capacity of a device has been exhausted. This forms the basis for the decisions on any possible further operation of the crane. The work presents an approach based on the provisions of standard ISO 12482: 2014. This document is the basis for service life evaluation for cranes. The approach presented in it makes the way of analysis dependent on the method used to collect operational data. In this paper the evaluation of service life expiration was prepared on the example of a ship to shore gantry cranes. These devices are characterized by particularly large dimensions and weight. Damage of their supporting structure can lead to the significant losses. Some of these devices change the location during operation. Therefore, it is important to know the current level of their service life usage. A case, in which the operational history of a device is not known, was considered. In the paper the special attention was paid to the methodology of estimating the load distribution coefficient. In order to describe the hypothetical load spectrum, triangular distribution was proposed. The results of the calculations for the structure of port cranes are presented and discussed.

PROGRAM OF PREDICTION AND MANAGEMENT OF COINTEGED DYNAMIC ECONOMIC PROCESSES BASED ON THE CYBERNETIC APPROACH

2019 ◽  
Author(s):  
Olena Bundak ◽  
Nataliia Zubovetska
Keyword(s):  
Computer Program ◽  
Pair Correlation ◽  
Time History ◽  
Critical Area ◽  
Concrete Object ◽  
Graphic Arts ◽  
Ex Post ◽  
History Of ◽  
Successive Change ◽  
Rms Errors

A method and computer program ConRow, which prognostication of development of the dynamically CPLD economic transients is executed by, is described in the article. Such prognostication of economic processes is very important in the cases when their development can result in undesirable consequences, that to go out in the so-called critical area. Extrapolation in a critical area with the use of information about the conduct of the system at an area, near to it, allows to estimate to the lead through of experiment in the critical area of his consequence. For the imitation of conduct of object the function of review is set on entrance influence. For a concrete object this function can express, for example, dependence of change of level sale from time-history of charges on advertising and set as a numeral row. Statistics as a result of analysis of row are represented in a table, where the level of meaningfulness is set statistician, and also parameters of the handed over criteria. The graphic reflection of information is intended for visualization of analysis. Here represented on the points of graphic arts, the crooked smoothing which are calculated as полиномиальные regressions is added. The best approaching is controlled by sight on the proper graph, and also by minimization of their rms errors. Models of prognostication by sight and as formulas represented on graphic arts, the middle is here determined tailings and their chance is checked up on statistics of signs. After the got models determined also and prognosis values of influences and reviews. Establishing an order models of Сr(p) of co integrate regression is carried out separate custom controls. The coefficient of clay correlation of ruФ shows by itself pair correlation between lines with a successive change in relation to each other on a size to лагу of l = 1, 2, 3 . The program was tested on the example of ex-post prognosis at establishing an integration connection and possibility of prognostication of growth of nominal average monthly settlings on the basis of these statistical indexes of consumer inflation in Ukraine.

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