A Fatigue-Life Model of a Rubber Bushing

1980 ◽  
Vol 53 (5) ◽  
pp. 1226-1238 ◽  
Author(s):  
H. L. Oh
Keyword(s):  
Fatigue Life ◽  
Energy Balance ◽  
Design Procedure ◽  
Test Results ◽  
Performance Requirement ◽  
Life Model ◽  
Rubber Bushing

Abstract A major performance requirement for a rubber bushing is durability. The model for fatigue life of a bushing given in Equation (4) was derived using an energy balance concept (energy available versus energy required to extend a tear). This model agreed well with test results. A design procedure was developed from the model which gives the optimum insert geometry for maximum bushing life.

Fatigue Life Calculation of the in-Service Dented Pipeline

2011 ◽  
Vol 467-469 ◽  
pp. 1327-1332 ◽  
Author(s):  
Wu Ying ◽  
Peng Zhang ◽  
Wu Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Life ◽  
Pressure Variation ◽  
Finite Element Models ◽  
Test Results ◽  
Peak Period ◽  
Factors Affecting ◽  
Life Model ◽  
Calculation Results

Dent is one of the important factors affecting pipeline fatigue life, and it will greatly reduce the fatigue life of the pipeline in service. Based on a large number of foreign dented pipeline fatigue test results and fatigue life model, for the typical dent defect, using finite element method, various parameters are changed and finite element models are obtained under different conditions. According to many calculation results, a key ratio of peak period stress and pipeline pressure variation are obtained, which are substituted to the fatigue life model and the example are calculated.

Paris Fatigue Life Modeling of Pressure Vessel Service Simulation Tests

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
John H. Underwood ◽  
John J. Keating ◽  
Edward Troiano ◽  
Gregory N. Vigilante
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Pressure Vessel ◽  
Base Alloy ◽  
Pressure Vessels ◽  
Full Scale ◽  
Test Results ◽  
X Ray Diffraction ◽  
Life Model ◽  
Nickel Base

Results from four groups of full-scale pressure vessel service simulation tests are described and analyzed using Paris fatigue life modeling. The objective is to determine how the vessel and initial crack configurations and applied and residual stresses control the as-tested fatigue life of the vessel. The tube inner radii are in the 40–80 mm range; wall thickness varies from 6 to 80 mm; materials are ASTM A723 pressure vessel steel and IN718 nickel-base alloy; applied internal pressure varies from 90 to 700 MPa. The Paris constant, C, and exponent, m, that describe the fatigue crack propagation rate versus stress intensity factor range for the various vessel materials, were measured as part of the investigation. Extensive, previously published fatigue life results from baseline A723 pressure vessels with well characterized autofrettage residual stresses and C and m values are used to demonstrate that a Paris fatigue life model gives a good description of the measured life. The same model is then used to determine the variables with predominant control over life in three types of pressure vessel for which less information and tests results are available. A design life for pressure vessels is calculated for a specified very low probability of fatigue failure using the log(N)-normal distribution statistics often used for fatigue of structures. The results of the work showed: (i) X-ray diffraction measurements of through-wall autofrettage residual stresses are in excellent agreement with prior neutron diffraction measurements from a baseline autofrettaged A723 pressure vessel; these verified autofrettage residual stresses then provide critical input to the baseline Paris life modeling; (ii) comparison of the various full-scale fatigue test results with results from the Paris fatigue life model shows close agreement when autofrettage residual stresses are incorporated into models; (iii) model results for A723 steel vessels with yield strength reduced from the initial 1400 MPa value and degree of autofrettage increased from the initial 40% value indicates a significantly improved resistance to brittle failure with no loss of fatigue life; (iv] comparison of model fatigue life results for IN718 nickel-base alloy vessels with their full-scale test results is improved when near-bore residual stresses measured by X-ray diffraction are included in the model calculations.

Fatigue Life of Ni-Based Single Crystal Super-Alloy Specimen with Single Hole

2021 ◽  
Vol 891 ◽  
pp. 10-16
Author(s):  
Xiang Zhen Xue ◽  
Zhi Xun Wen ◽  
Wen Xian Li
Keyword(s):  
Fatigue Life ◽  
Single Crystal ◽  
Stress Ratio ◽  
Test Results ◽  
Alloy Specimen ◽  
Paris Law ◽  
Single Hole ◽  
Alloy Material ◽  
Life Model ◽  
Super Alloy

A method of predicting the fatigue life under multiaxis loads based on the Paris law and EIFS was proposed. And the fatigue life under different loading stress and stress ratio were investigated. The results show that when the loading stress increased from 450~800 MPa, the fatigue life decreased from 6762379 to 10056, as well as when the stress ratio increased from 0.1~1, the fatigue life increased from 6762379 to 14932368. It was validated by test eventually. And the fatigue life model presented here agrees well with test results. It is significant to the prediction of turbine of Ni-based single crystal super-alloy material with filming hole.

Study on the stiffness degradation in concrete continuous beam with externally prestressed CFRP tendons under fatigue loading

2021 ◽  
pp. 136943322199249
Author(s):  
Xing Li ◽  
Jiwen Zhang ◽  
Jun Cheng
Keyword(s):  
Fatigue Life ◽  
Fatigue Loading ◽  
Load Level ◽  
Fiber Reinforced Polymer ◽  
Stiffness Degradation ◽  
Test Results ◽  
Reinforced Polymer ◽  
Continuous Beams ◽  
Practical Engineering ◽  
Good Agreement

This paper presents fatigue behaviors and the stiffness degradation law of concrete continuous beams with external prestressed carbon fiber-reinforced polymer (CFRP) tendons. Three specimens were tested under fatigue loading, and the influence of different load levels on the stiffness degradation and fatigue life were studied, and it was found that the stiffness degradation of three test specimens exhibited a three-stage change rule, namely rapid decrease, stable degradation, and sharp decline, but there are obvious differences in the rate and amplitude of stiffness degradation. The load level has a significant influence on the fatigue life of the test specimens. An analytical model with load level considered was proposed to calculate the residual stiffness and predict the stiffness degradation, which is in good agreement with the test results. The model of stiffness degradation presents a possible solution for practical engineering applications of concrete continuous beams with externally prestressed CFRP tendons subjected to different fatigue loadings.

scholarly journals Impact of Graphene Oxide on Zero Shear Viscosity, Fatigue Life and Low-Temperature Properties of Asphalt Binder

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3073
Author(s):  
Abbas Mukhtar Adnan ◽  
Chaofeng Lü ◽  
Xue Luo ◽  
Jinchang Wang
Keyword(s):  
Graphene Oxide ◽  
Fatigue Life ◽  
Low Temperature ◽  
Shear Viscosity ◽  
Storage Stability ◽  
Asphalt Binder ◽  
Asphalt Binders ◽  
Test Results ◽  
Zero Shear Viscosity ◽  
Modified Asphalt

This study has investigated the impact of graphene oxide (GO) in enhancing the performance properties of an asphalt binder. The control asphalt binder (60/70 PEN) was blended with GO in contents of 0%, 0.5%, 1%, 1.5%, 2%, and 2.5%. The permanent deformation behavior of the modified asphalt binders was evaluated based on the zero shear viscosity (ZSV) parameter through a steady shear test approach. Superpave fatigue test and the linear amplitude sweep (LAS) method were used to evaluate the fatigue behavior of the binders. A bending beam rheometer (BBR) test was conducted to evaluate the low-temperature cracking behavior. Furthermore, the storage stability of the binders was investigated using a separation test. The results of the ZSV test showed that GO considerably enhanced the steady shear viscosity and ZSV value, showing a significant contribution of the GO to the deformation resistance; moreover, GO modification changed the asphalt binder’s behavior from Newtonian to shear-thinning flow. A notable improvement in fatigue life was observed with the addition of GO to the binder based on the LAS test results and Superpave fatigue parameter. The BBR test results revealed that compared to the control asphalt, the GO-modified binders showed lower creep stiffness (S) and higher creep rate (m-value), indicating increased cracking resistance at low temperatures. Finally, the GO-modified asphalt binders exhibited good storage stability under high temperatures.

scholarly journals Analysis of the Correlation between the Static and Fatigue Test Results of the Interlayer Bondings of Asphalt Layers

2016 ◽  
Vol 62 (1) ◽  
pp. 83-98 ◽  
Author(s):  
A. Szydło ◽  
K. Malicki
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Asphalt Mixture ◽  
Fatigue Tests ◽  
Test Results ◽  
Static Tests ◽  
Bonding State ◽  
Road Pavement ◽  
The Future ◽  
Pavement Structure

Abstract The bonding state of the asphalt layers in a road pavement structure significantly affects its fatigue life. These bondings, therefore, require detailed tests and optimization. In this paper, the analyses of the correlation between the results of laboratory static tests and the results of fatigue tests of asphalt mixture interlayer bondings were performed. The existence of the relationships between selected parameters was confirmed. In the future, the results of these analyses may allow for assessment of interlayer bondings’ fatigue life based on the results of quick and relatively easy static tests.

High-cycle fatigue tests of pretensioned concrete beams

PCI Journal ◽  
2022 ◽  
Vol 67 (1) ◽  
Author(s):  
Jörn Remitz ◽  
Martin Empelmann
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Concrete Beams ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Design Methods ◽  
Test Results ◽  
Cycle Fatigue ◽  
Pretensioned Concrete ◽  
Current Design

Pretensioned concrete beams are widely used as bridge girders for simply supported bridges. Understanding the fatigue behavior of such beams is very important for design and construction to prevent fatigue failure. The fatigue behavior of pretensioned concrete beams is mainly influenced by the fatigue of the prestressing strands. The evaluation of previous test results from the literature indicated a reduced fatigue life in the long-life region compared with current design methods and specifications. Therefore, nine additional high-cycle fatigue tests were conducted on pretensioned concrete beams with strand stress ranges of about 100 MPa (14.5 ksi). The test results confirmed that current design methods and specifications overestimate the fatigue life of embedded strands in pretensioned concrete beams.

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