scholarly journals The Cumulative Fatigue Damage under Axial Stationary Random Loading : Part 1 Fatigue Test Results on Unnotched Specimens of Carbon Steels

1969 ◽  
Vol 35 (278) ◽  
pp. 2020-2031 ◽  
Author(s):  
Makoto KIKUKAWA ◽  
Kiyotsugu OHJI ◽  
Masahiro JONO ◽  
Takao MIZOGUCHI
Keyword(s):  
Fatigue Test ◽  
Fatigue Damage ◽  
Carbon Steels ◽  
Test Results ◽  
Random Loading ◽  
Cumulative Fatigue Damage

Pipeline Plain Dent Fatigue: A Comparison of Assessment Methodologies

2014 ◽  
Author(s):  
Sérgio B. Cunha ◽  
Ilson P. Pasqualino ◽  
Bianca C. Pinheiro
Keyword(s):  
Fatigue Test ◽  
Fatigue Damage ◽  
Fatigue Tests ◽  
Full Scale ◽  
Assessment Methodology ◽  
Test Results ◽  
Different Shapes ◽  
Cumulative Fatigue Damage ◽  
X80 Steels ◽  
Damage Rule

A collection of results of fatigue tests undertaken on full scale pipeline specimens containing unconstrained plain dents is presented. A total of 61 test results are reported, comprising dents of different shapes and depths, introduced in pipe sections with nominal diameters of 12″ and 24″, D/t ratios varying from 18.6 to 77.2 and made of API 5L X42, X46, X52, X60, X70 and X80 steels. The fatigue test results are used to compare five plain dent fatigue assessment methodologies. The assessment methodologies most widely used in the industry, namely, API 1156 and EPRG, are evaluated; each one of these has two different versions, evaluated independently. A dent assessment methodology previously proposed by the authors is also is included in the study. The classic Palmgren-Miner’s cumulative fatigue damage rule is employed in order to correlate the results, since all tests were carried out with two different pressure cycles. Only two of the evaluated methodologies presented a correlation with the fatigue tests that justifies recommending their application in the industry.

Estimation of Cumulative Fatigue Damage Under Random Loading

1976 ◽  
Vol 98 (1) ◽  
pp. 348-353 ◽  
Author(s):  
A. K. Abu-Akeel
Keyword(s):  
Fatigue Damage ◽  
Computation Time ◽  
Straight Line Segment ◽  
Computer Applications ◽  
Accurate Estimation ◽  
Random Loading ◽  
Structural Element ◽  
Load Curve ◽  
Straight Line ◽  
Cumulative Fatigue Damage

A method is presented that leads to accurate estimation of the cumulative fatigue damage incurred in a randomly loaded structural element when loading is given in the form of spectral density load, or stress, plots. The load plots are here approximated by a series of straight lines and a closed formula is obtained to yield the damage incurred by the load within each straight line segment. The method avoids the errors that result from human misjudgment in the commonly used curve-stepping approach. It is also adaptable for computer applications and can be incorporated in a stress calculation program to save on computation time. In comparison to curve stepping, five straight-line segments may give the same accuracy as a hundred curve steps. This contrast, however, depends on the degree of irregularity of the load curve.

Fatigue Performance of Grade R4 and R5 Mooring Chains in Seawater

2014 ◽  
Author(s):  
Jonathan Fernández ◽  
Walther Storesund ◽  
Jesús Navas
Keyword(s):  
Fatigue Test ◽  
Fatigue Damage ◽  
Fatigue Tests ◽  
Design Methods ◽  
Full Scale ◽  
Fatigue Performance ◽  
Test Program ◽  
Gas Industry ◽  
Fatigue Design ◽  
Cumulative Fatigue Damage

With more than 50.000 tons in service to date, the Oil&Gas Industry has the need to understand the tension fatigue performance of grade R5 chains in straight tension, and corroborate the validity of the existing design methods. The chain fatigue design curves in API and DNV are based on fatigue tests obtained in the nineties and early two thousands. However the tests were performed on lower grades such as ORQ, R3 and R4, and small chains, 76 mm diameter being the largest studless chain tested. The industry has moved towards the use of large studless chains, especially in permanent units, where chain diameters above 150 mm are not unusual. This paper gathers information from a full scale fatigue test program on grade R4 and R5 studless chains, performed in seawater and with diameters between 70 mm and 171 mm. The chains being tested are actual production chains supplied for different drilling units and large permanently moored production floating units. The paper analyses the data and determines tension-tension fatigue curves based on API and DNV methods for computation of cumulative fatigue damage, regardless of other damaging mechanisms. Improved fatigue capacity is obtained with respect to the above recommended design methods.

The Fatigue Behavior of Steel Structures under Random Loading

2008 ◽  
Vol 378-379 ◽  
pp. 3-16
Author(s):  
Henning Agerskov
Keyword(s):  
Fracture Mechanics ◽  
Fatigue Test ◽  
Steel Structures ◽  
Fatigue Tests ◽  
Test Series ◽  
Test Results ◽  
Random Loading ◽  
Mechanics Analysis ◽  
Miner’S Rule ◽  
Miner's Rule

Fatigue damage accumulation in steel structures under random loading has been studied in a number of investigations at the Technical University of Denmark. The fatigue life of welded joints has been determined both experimentally and from a fracture mechanics analysis. In the experimental part of the investigation, fatigue test series with a total of 540 fatigue tests have been carried through on various types of welded plate test specimens and full-scale offshore tubular joints. The materials that have been used are either conventional structural steel or high-strength steel. The fatigue tests and the fracture mechanics analyses have been carried out using load histories, which are realistic in relation to the types of structures studied, i.e. primarily bridges, offshore structures and chimneys. In general, the test series carried through show a significant difference between constant amplitude and variable amplitude fatigue test results. Both the fracture mechanics analysis and the fatigue test results indicate that Miner’s rule, which is normally used in the design against fatigue in steel structures, may give results, which are unconservative, and that the validity of the results obtained from Miner’s rule will depend on the distribution of the load history in tension and compression.

Cumulative Fatigue Damage With Random Loading

1962 ◽  
Vol 84 (3) ◽  
pp. 403-408 ◽  
Author(s):  
R. R. Gatts
Keyword(s):  
Fatigue Damage ◽  
Stress Amplitude ◽  
Amplitude Distribution ◽  
General Concept ◽  
Time Function ◽  
Discrete Distributions ◽  
Random Loading ◽  
Linear Rule ◽  
Cumulative Fatigue Damage ◽  
Distribution Of Stress

A general concept of the accumulation of fatigue damage is applied where stress amplitude is a random time function with a specified amplitude distribution. A differential equation relating damage accumulation to the amplitude distribution of stress is derived. This equation is applicable to both continuous and discrete distributions. Solutions of the equation are used to predict life under random loading on the basis of constant amplitude S-N data. Such predictions are compared for both continuous and discrete stress amplitude distributions and found in better over-all agreement with the data than comparable predictions by the linear rule.

Cumulative Fatigue Damage Under Stress-Controlled Conditions

1971 ◽  
Vol 93 (4) ◽  
pp. 691-698 ◽  
Author(s):  
Thang Bui Quoc ◽  
J. Dubuc ◽  
A. Bazergui ◽  
A. Biron
Keyword(s):  
Theoretical Analysis ◽  
Fatigue Damage ◽  
Experimental Results ◽  
Published Data ◽  
Mean Stress ◽  
Remaining Life ◽  
Random Loading ◽  
Controlled Conditions ◽  
Cumulative Fatigue Damage ◽  
Good Agreement

A theoretical analysis of uniaxial cumulative fatigue damage is presented together with a large number of experimental results on unnotched specimens of A-201 and A-517 steels. The theory developed permits the prediction of fatigue curves for stress-controlled conditions with zero or positive mean stress as well as the evaluation of the damage accumulated during a fatigue test and hence the prediction of the remaining life of a specimen. Theory is in good agreement with the experimental results as well as with published data on other materials. The development may be extended to other types of tests such as strain-controlled or random loading conditions.

Nonlinear Fatigue Damage Accumulation Under Random Loading

1996 ◽  
Vol 118 (2) ◽  
pp. 168-173 ◽  
Author(s):  
W. Q. Zhu ◽  
M. X. Jiang
Keyword(s):  
Fatigue Damage ◽  
Damage Accumulation ◽  
Stochastic Theory ◽  
Reliability Function ◽  
Random Loading ◽  
Fatigue Damage Accumulation ◽  
Probability Densities ◽  
Cumulative Fatigue Damage ◽  
Analytical Expressions ◽  
Damage Rule

The analytical expressions for the probability densities of the cumulative fatigue damage and fatigue life and for the reliability function are obtained for a mechanical or structural component subject to stationary random stress process on the basis of a stochastic theory of fatigue damage accumulation proposed by the first author and his co-worker and the Morrow’s nonlinear damage rule. The comparison between the results from Morrow’s and Palmgren-Miner’s damage rules for the case when the stress is a narrow-band stationary Gaussian process with zero mean is made and some important conclusions are drawn.

Random Fatigue Analysis of Automotive Bevel Gear

2006 ◽  
Vol 326-328 ◽  
pp. 987-990 ◽  
Author(s):  
Duck Hoi Kim ◽  
Jae Hoon Kim ◽  
Gi Gwang Kim ◽  
Young Shin Lee
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Fatigue Analysis ◽  
Bevel Gear ◽  
Test Results ◽  
Random Loading ◽  
Bending Fatigue ◽  
Bending Fatigue Strength ◽  
Applied Stresses ◽  
Random Fatigue

The most common mode of the gear failure is tooth breakage, which is usually produced by bending fatigue failure. It is important to manufacture the gears which can withstand the applied stresses in view of safety and economic requirements. In this study, fatigue test and analysis were performed to evaluate the bending fatigue strength of an automotive bevel gear. Test fixtures of the double tooth concept were considered to obtain reliable fatigue test results. Fatigue life of automotive bevel gear was evaluated by Weibull analysis. To compare the test results and to verify the fatigue analysis procedures, fatigue analyses were carried out. The results of fatigue analysis show that fatigue life and crack initiation sites were well agreed with test results. The random loading of bevel gear under the real driving conditions was defined here, and then the fatigue analysis under random loading was also performed.

Sign in / Sign up

Export Citation Format

Share Document