Weibull analysis for normal/accelerated and fatigue random vibration test

Based on the true stress, the ultimate material’s strength, and the fatigue slope b values, the probabilistic percentiles of the S-N curve of ductile materials are formulated. The Weibull β and η parameters used to determine the product’s reliability are determined directly from the material’s strength values corresponding to 103 and 106 cycles. And since in Table corresponding to the properties of this A538 A (b) steel and collected by table 23-A of Shigley Mechanical Engineering Design book; authors present the σt, Sut, and b values of several materials, then the Weibull parameters for each one of these materials as well as the 95% and 5% reliability percentiles of their S-N curves are given. A step-by-step application to the steel A538 A (b) material is presented. And based on the maximum and minimum applied stress values, the corresponding Weibull stress distribution was fitted and used with the Weibull strength distribution, in the stress/strength reliability function to determine the element’s reliability.

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“…In practice, it is R(n)=0.9535. And it corresponds to test a set of n=21 parts [11]. From [11], the relation between R(n) and n is given as…”

Section: Steps To Determine the Weibull Strength Parametersmentioning

confidence: 99%

Weibull strength distribution and reliability S-N percentiles for tensile tests

Baro¹,

Piña‐Monarrez

Barraza-Contreras

2022

Rev. Ci. Tec.

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“…The Weibull distribution is also a life distribution that is frequently applied and used in the field of reliability. 30 The probability density function of the Weibull distribution is expressed by (5).…”

Section: Adt With Extremely High Temperaturesmentioning

confidence: 99%

Lifetime estimation for optocouplers using accelerated degradation test

Kang

Lee

Park

et al. 2021

Quality & Reliability Eng

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Instrumentation and control systems significantly affect the safety and reliability of nuclear power plants. In this study, we analyze the cause of failure of the electronic card constituting the instrumentation and control system as it is the most typical reason for the failure of optocouplers. The lifetime of optocouplers must be predicted accurately to ensure high-reliability nuclear power plants. While acceleration tests have been performed to predict the lifetime of optocouplers more efficiently, it is preferable to perform accelerated degradation tests rather than accelerated life tests. In this paper, accelerated degradation tests are performed on optocouplers at various temperatures and voltages. To derive the degradation curve model of the optocoupler using the results of accelerated degradation tests, we use the most suitable model from OriginLab. The parameter values of the proposed degradation curve model are calculated by applying the Arrhenius model and Weibull distribution, and the lifetime of the optocoupler is estimated by using the proposed degradation curve model.

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“…Based on Piña-Monarrez [21] and on the addressed maximum = and minimum = values, the Weibull scale parameter is directly given by: Following the above S-N fatigue strength analysis, the proposed method to design the A572 Gr. 50 S-N curve is now presented.…”

Section: Fatigue Strength Analysis Based On Weibull Approachmentioning

confidence: 99%

“…Based on Piña-Monarrez [21] and on the addressed maximum (S f ) 10 3 = S max and minimum (S f ) 10 6 = S min values, the Weibull scale parameter is directly given by:…”

Section: Fatigue Strength Analysis Based On Weibull Approachmentioning

confidence: 99%

Weibull S-N Fatigue Strength Curve Analysis for A572 Gr. 50 Steel, Based on the True Stress—True Strain Approach

Molina¹,

Piña‐Monarrez²,

Barraza-Contreras³

2020

Applied Sciences

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In this paper a Weibull methodology to determine the probabilistic percentiles for the S-N curve of the A572 Gr. 50 steel is formulated. The given Weibull/S-N formulation is based on the true stress and true strain values, which are both determined from the stress-strain analysis. For the analysis, the Weibull β and η parameters are both determined directly from the maximum and minimum addressed stresses values. The S-N curve parameters are determined for 103 and 106 cycles. In the application, published experimental data for the CSA G40.21 Gr. 350W steel is used to derive the true stress and true strain parameters of the A572 Gr. 50 steel. Additionally, the application of the S-N curve, its probabilistic percentiles and the Weibull parameters that represent these percentiles are all determined step by step. Since the proposed method is flexible, then it can be applied to determine the probabilistic percentiles of any other material.

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Weibull analysis for normal/accelerated and fatigue random vibration test

Cited by 9 publications

References 16 publications

Weibull strength distribution and reliability S-N percentiles for tensile tests

Weibull strength distribution and reliability S-N percentiles for tensile tests

Lifetime estimation for optocouplers using accelerated degradation test

Weibull S-N Fatigue Strength Curve Analysis for A572 Gr. 50 Steel, Based on the True Stress—True Strain Approach

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