Determination of fatigue life for low probability of failure for different stress levels using 3-parameter Weibull distribution

2021 ◽  
Vol 145 ◽  
pp. 106080
Author(s):  
Przemysław Strzelecki
Keyword(s):  
Fatigue Life ◽  
Weibull Distribution ◽  
Probability Of Failure ◽  
Stress Levels ◽  
Low Probability

scholarly journals Flexural-Fatigue Properties of Sustainable Pervious Concrete Pavement Material Containing Ground Tire Rubber and Silica Fume

2019 ◽  
Vol 11 (16) ◽  
pp. 4467 ◽  
Author(s):  
Hanbing Liu ◽  
Guobao Luo ◽  
Peilei Zhou ◽  
Haibin Wei ◽  
Wenjun Li ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Weibull Distribution ◽  
Silica Fume ◽  
Pervious Concrete ◽  
Likelihood Method ◽  
Tire Rubber ◽  
Ground Tire Rubber ◽  
Survival Probabilities ◽  
Stress Levels ◽  
Two Parameter

With the development of urbanization, pervious concrete has been increasingly used in urban road pavement structures. The objective of this paper was to investigate the effect of stress levels and modifier (ground tire rubber and silica fume) on the fatigue life of pervious concrete and establish the fatigue equations with different survival probabilities. In order to improve the deformability of pervious concrete without sacrificing its strength, ground tire rubber and silica fume were added into pervious concrete. Two kinds of pervious concrete, control pervious concrete and ground tire rubber and silica fume modified pervious concrete, were made in the laboratory. The pervious concrete beam specimens of 100 × 100 × 400 mm were casted, and the static flexural strength and flexural strain of the two kinds of pervious concrete were tested. The fatigue lives of two pervious concretes were tested using MTS fatigue testing machine under four different stress levels (0.85, 0.80, 0.75, and 0.70). The fatigue life was analyzed by two-parameter Weibull distribution. The parameters of Weibull distribution were determined by graphical method, maximum likelihood method and moment method. The Kolmogorov–Smirnov test was used to test the Weibull distribution and the fatigue equations under different survival probabilities were established. The results showed that ground tire rubber and silica fume modified pervious concrete had better deformability while ensuring strength compared to control pervious concrete. The addition of ground tire rubber and silica fume improved the fatigue life of pervious concrete. The two-parameter Weibull distribution was suitable to characterize the fatigue characteristics and predict the fatigue life of pervious concrete. Fatigue equations with different survival probabilities were a good guide for pervious concrete design.

A Method for Estimating Parameters of P-S-N Curves Based on Weibull Distribution

2011 ◽  
Author(s):  
Dan Ling ◽  
Shun-Peng Zhu ◽  
Hong-Zhong Huang ◽  
Li-Ping He ◽  
Zhong-Lai Wang
Keyword(s):  
Fatigue Life ◽  
Maximum Likelihood ◽  
Maximum Likelihood Estimation ◽  
Weibull Distribution ◽  
Stress Level ◽  
Likelihood Estimation ◽  
Probability Of Failure ◽  
Unknown Parameters ◽  
Curve Model ◽  
The Relationship

An S-N curve is a traditional tool for design against fatigue. Because there is often a considerable amount of scatter in fatigue performance of specimens, The P-S-N curves capturing the probability of failure should be employed instead of S-N curves. In order to minimize the time and the number of specimens required for fatigue test, many researches had been done. Most studies were focused on a three-parameter S-N curve model; lognormal distribution and maximum likelihood estimation were employed to estimate unknown parameters. In this paper, a three-parameter Weibull distribution is used to describe the scatter of fatigue life. The relationship among survival probability, stress level and fatigue life is considered. A method for estimating parameters of P-S-N curves is proposed. According to this method, three groups of specimens are needed. Each group is submitted to a stress level. The parameters of P-S-N curves can be estimated by solving a set of nonlinear equations. And a numerical example shows that the method is effective.

Determination of Minimum Number of Specimens in S-N Testing

2002 ◽  
Vol 124 (4) ◽  
pp. 421-427 ◽  
Author(s):  
Prakash Chandra Gope
Keyword(s):  
Distribution Function ◽  
Fatigue Life ◽  
Weibull Distribution ◽  
Functional Relationship ◽  
Minimum Sample Size ◽  
Life Data ◽  
Minimum Number ◽  
Log Normal ◽  
Minimum Number Of Specimens

A method for determination of minimum sample size required to estimate the fatigue life has been presented. No functional relationship between stress and fatigue life other than log normal and Weibull distribution function of fatigue life has been assumed. The method is based on the analysis of the variance of error which arises due to scattered nature of the fatigue life data. An example of the application of the presented method is also given.

Energy for crack growth in model rubber components

1972 ◽  
Vol 7 (2) ◽  
pp. 132-140 ◽  
Author(s):  
P B Lindley
Keyword(s):  
Fatigue Life ◽  
Crack Growth ◽  
Crack Surface ◽  
Uniform Stress ◽  
Numerical Techniques ◽  
Surface Displacements ◽  
Tearing Energy ◽  
Crack Growth Rates ◽  
Essential Prerequisite

The determination of tearing energy, i.e. the energy available for crack growth, is an essential prerequisite for the estimation of the fatigue life of rubber components. Three methods of determining tearing energy are considered: from changes in total energy, from crack surface displacements, and by comparison with known values for the same crack growth rates. It is shown by applying experimental and numerical techniques to plane-stress testpieces, not necessarily of uniform stress or thickness, that the methods are satisfactory.

Direct Determination of Stress Levels in Sputtered Films by means of X-Ray Diffraction Topographic Method

1987 ◽  
Vol 26 (Part 1, No. 1) ◽  
pp. 157-161 ◽  
Author(s):  
Osamu Nittono ◽  
Yoshihiro Sadamoto ◽  
Sheng Kai Gong
Keyword(s):  
Direct Determination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sputtered Films ◽  
Stress Levels

Design Formulas of Blind End Closures for High Pressure Vessels

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
R. D. Dixon ◽  
E. H. Perez
Keyword(s):  
High Pressure ◽  
Fatigue Life ◽  
Maximum Stress ◽  
Accurate Determination ◽  
Pressure Vessels ◽  
Stress Distributions ◽  
Fatigue And Fracture ◽  
Asme Code ◽  
Section Viii

The available design formulas for flat heads and blind end closures in the ASME Code, Section VIII, Divisions 1 and 2 are based on bending theory and do not apply to the design of thick flat heads used in the design of high pressure vessels. This paper presents new design formulas for thickness requirements and determination of peak stresses and stress distributions for fatigue and fracture mechanics analyses in thick blind ends. The use of these proposed design formulas provide a more accurate determination of the required thickness and fatigue life of blind ends. The proposed design formulas are given in terms of the yield strength of the material and address the fatigue strength at the location of the maximum stress concentration factor. Introduction of these new formulas in a nonmandatory appendix of Section VIII, Division 3 is recommended after committee approval.

Fatigue Life Assessment of Self-Expandable NiTi Stent

2014 ◽  
Vol 627 ◽  
pp. 45-48
Author(s):  
Cristian Sorin Nes ◽  
Angelica Enkelhardt ◽  
Lucian Bogdan ◽  
Nicolae Faur
Keyword(s):  
Fatigue Life ◽  
Arterial Wall ◽  
Cylindrical Tube ◽  
Life Assessment ◽  
Cyclic Loads ◽  
Fatigue Life Assessment ◽  
A Value ◽  
Vessel Stenosis ◽  
Fatigue Characteristics

Objectives: This paper presents a numerical fatigue life assessment of a self-expandable Nitinol stent. The analysis was performed using the ANSYS 11 software. Methods: Stent durability is an issue which must be addressed during the design of implants. Given the corrosive properties of blood and the cyclic loads that are applied on the stent (the cyclic variation of blood pressure), the determination of fracture parameters and fatigue characteristics of the implant is highly recommended. Breaking of the stent’s wire is particularly dangerous because it can cause the dislocation of a piece of stenotic plaque, which in turn can block a smaller artery, causing a heart attack. On the other hand, any discontinuity in stent structure acts as an accumulating place for stenosis particles, significantly shortening the life of the implant. The stent consists of a cylindrical tube 22.42 mm long, with a diameter of 8.3 millimeters. The wire section is square, 0.2x0.2 millimeters. The stent is only subjected to the pressure generated by the stenoted arterial wall. This evenly distributed pressure is defined at the outer surface of the stent and has a value of 2.5 MPa, corresponding to a 56% blood vessel stenosis. This way, the most severe loading conditions for the stent could be simulated. The stress distribution was then used to asses the fatigue life of the stent. Results and conclusions: The results showed that, in normal conditions (with the maximal internal pressure of 139 mm Hg = 18533 Pa), no damage appears on the stent after 107 cycles.

Sign in / Sign up

Export Citation Format

Share Document