Temperature dependence of stress–fatigue life data of FRP composites

2011 ◽  
Vol 47 (2) ◽  
pp. 185-192 ◽  
Author(s):  
H. Mivehchi ◽  
A. Varvani-Farahani
Keyword(s):  
Fatigue Life ◽  
Temperature Dependence ◽  
Life Data ◽  
Frp Composites ◽  
Stress Fatigue

scholarly journals Bayesian estimation of the lethargy coefficient for probabilistic fatigue life model

2017 ◽  
Vol 5 (2) ◽  
pp. 191-197 ◽  
Author(s):  
Jaehyeok Doh ◽  
Jongsoo Lee
Keyword(s):  
Fatigue Life ◽  
Sampling Method ◽  
Bayesian Updating ◽  
Unknown Parameters ◽  
Life Data ◽  
Mcmc Sampling ◽  
Fatigue Model ◽  
Relative Stress ◽  
Life Model ◽  
Static Tensile

Abstract In this study, a model for probabilistic fatigue life that is based on the Zhurkov model is suggested using stochastically and statistically estimated lethargy coefficients. The fatigue life model was derived using the Zhurkov life model, and it was deterministically validated using real fatigue life data as a reference. For this process, firstly, a lethargy coefficient that is related to the failure of materials must be obtained with rupture time and stress from a quasi-static tensile test. These experiments are performed using HS40R steel. However, the lethargy coefficient has discrepancies due to the inherent uncertainty and the variation of material properties in the experiments. The Bayesian approach was employed for estimating the lethargy coefficient of the fatigue life model using the Markov Chain Monte Carlo (MCMC) sampling method and considering its uncertainties. Once the samples are obtained, one can proceed to the posterior predictive inference of the fatigue life. This life model was shown to be reasonable when compared with experimental fatigue life data. As a result, predicted fatigue life was observed to significantly decrease in accordance with increasing relative stress conditions. Highlights Zhurkov fatigue life model is deterministically validated with experiments. Prediction of the S-N curve using Zhurkov fatigue model and lethargy coefficients. Lethargy coefficients of Zhurkov fatigue model are estimated by Bayesian updating. Bayesian updating is useful for quantifying the uncertainty of unknown parameters.

scholarly journals The Influence of the Carbo-Glass Geogrid-Reinforcement on the Fatigue Life of the Asphalt Pavement Structure / Wpływ Zbrojenia Siatka Weglowo–Szklana Na Trwałosc Zmeczeniowa Asfaltowej Nawierzchni Drogowej

2012 ◽  
Vol 58 (1) ◽  
pp. 97-113 ◽  
Author(s):  
J. Górszczyk ◽  
S. Gaca
Keyword(s):  
Fatigue Life ◽  
Asphalt Pavement ◽  
Field Tests ◽  
Traffic Loading ◽  
Geogrid Reinforcement ◽  
Traffic Conditions ◽  
Pavement Structure ◽  
Number Of Cycles ◽  
The One ◽  
Stress Fatigue

Abstract This paper describes the analyses of the fatigue life of the asphalt pavement reinforced with geogrid interlayer under traffic loading. Finite Element ANSYS package with using nCode applications, as well as macros specially designed in APDL programming script and VBA were used to model the considered problem. Our analysis included computation of stress, fatigue life, damage matrix and rainflow matrix. The method applied was the one of fatigue calculation: stress - number of cycles in short S-N. On the basis of the performed high cycle fatigue analysis, the influence of the location of the used geogrid and of its bond with asphalt layers on the fatigue life and the work of the asphalt pavement structure were determined. The study was carried out for three temperature seasons i.e. spring and fall (assumed as one season), winter and summer. The variability of the traffic conditions were taken into account by assuming weekly blocks of traffic loading. The calculations were made using the real values of loading measured in field tests on the German highways by means of HS-WIM weighing system. As a result of the performed tests, it was proved that the use of geogrid-reinforcement may prolong the fatigue life of the asphalt pavement. However, it is required that: the geogrid should be located in the tension zone as low as possible in the structure of the asphalt layers. Moreover, it is necessary to provide high stiffness of the bond between the geogrid and the asphalt layers.

Capturing uncertainty in fatigue life data

2015 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Ravi C. Penmetsa ◽  
Raymond R. Hill ◽  
Darryl K. Ahner ◽  
Brent D. Russell
Keyword(s):  
Fatigue Life ◽  
Life Data

The Influence of Friction Coefficient on Tenon/Groove Contact Performance in Nickel-Based Turbine Blade-Disc

2014 ◽  
Vol 940 ◽  
pp. 74-80 ◽  
Author(s):  
Guo Cai Zhou ◽  
Zhi Xun Wen ◽  
Zhu Feng Yue ◽  
Yu Fen Gao
Keyword(s):  
Fatigue Life ◽  
Friction Coefficient ◽  
Contact Stress ◽  
Crystallographic Orientation ◽  
Contact Region ◽  
Complex Loading ◽  
Plastic Slip ◽  
Rate Dependent ◽  
Stress Fatigue ◽  
The Relationship

This paper presented the influence of crystallographic orientation and friction coefficient on the contact stress and fatigue life in the tenon/groove contact region. A rate-dependent crystallographic plastic slip theory was used to calculate the contact stress and fatigue life in [001], [011] and [111] orientations. In the calculation, complex loading conditions and different friction coefficients of 0, 0.2, 0.4, 0.6, 0.8 and 1.0 were taken into account in tenon/groove. Then the relationship between contact stress, fatigue life and friction coefficient was discussed. Simulation results show that: friction coefficient and crystallographic orientation have significant effect on contact stress and fatigue life. Contact stress in [001], [011] and [111] orientation increases with increasing friction coefficient generally. For [001] and [011] orientation, the fatigue life decreases with increasing friction coefficient firstly. When friction coefficient is 0.4, the fatigue life meets its minimum. Then the fatigue life will increase with increasing friction coefficient. For [111] orientation, the change of fatigue life has no obvious trend, and while friction coefficient exceeds 0.6, the life almost constant.

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