Time-Dependent Strength Degradation and Reliability of an Alumina Ceramic Subjected to Biaxial Flexure

2008 ◽  
pp. 325-325
Author(s):  
Luen-Yuan Chao ◽  
Dinesh K. Shetty
Keyword(s):  
Strength Degradation ◽  
Alumina Ceramic ◽  
Time Dependent ◽  
Biaxial Flexure

Modelling Strength Degradation Phenomena and Inspections Used for Reliability Assessment Based on Maintenance Planning

2006 ◽  
Author(s):  
Y. Garbatov ◽  
C. Guedes Soares ◽  
D. Ok ◽  
Y. Pu ◽  
C. M. Rizzo ◽  
...  
Keyword(s):  
Time Variation ◽  
Probabilistic Models ◽  
Reliability Assessment ◽  
Strength Degradation ◽  
Probability Of Detection ◽  
Ship Hull ◽  
Time Dependent ◽  
Maintenance Planning

The work reviews different probabilistic models of strength degradation of steel ship hull structures considering time dependent corrosion phenomena. Different models of time variation of the degradation phenomena are analyzed as well as the probability of detection and different inspection methods associated with each phenomenon is discussed.

A Stress-Strength Interference Model with Strength Degradation Following a Gamma Process

2014 ◽  
Vol 945-949 ◽  
pp. 1196-1200
Author(s):  
Jian Cheng Shen ◽  
Li Mei Liu ◽  
Ai Sheng Jiao ◽  
Xiang Bin Yi
Keyword(s):  
Poisson Process ◽  
Integration Method ◽  
Strength Degradation ◽  
Gamma Process ◽  
Time Dependent ◽  
Interference Model ◽  
Common Phenomenon ◽  
Numerical Integration Method ◽  
Structure Reliability ◽  
Over Time

Stress-strength interference model has been widely used for reliability analysis of structures.Strength degradation of a structure is a common phenomenon in engineering. To evaluate the structure reliability in the case of strength degradation over time, the strength degradation is represented by a gamma process and the stress applied on a structure is represented by the Poisson process in this paper. Then a time-dependent stress-strength interference model is suggested by employing numerical integration method. With this model, the structure reliability can be evaluated more accurately.

Critical issues In The Mechanical Reliability of Lightguide Fibers

1998 ◽  
Vol 531 ◽  
Author(s):  
C. R. Kurkjian
Keyword(s):  
Time Dependence ◽  
Safety Factor ◽  
Strength Degradation ◽  
Time Dependent ◽  
Mechanical Reliability ◽  
Strength Limit ◽  
Dependent Behavior ◽  
Critical Issues

AbstractIn order to guarantee a minimum initial strength, lightguide fibers are proof-tested. However, the strength of these fibers is known to depend on time (due to fatigue and aging) and this time-dependence must be taken into account in the calculation of fiber lifetimes. While hermetic coatings can be applied to eliminate strength degradation with time, they are rarely used. It is thus necessary to understand the time-dependent behavior well enough to ensure a desired lifetime (without an excessive and costly safety factor), or alternatively, it is necessary to validate a fundamental strength limit. This paper discusses the progress that has been made on issues related to such fiber lifetime predictions. In particular, it is pointed out that the possible variations in flaw character and coating chemistry make simple generalizations difficult and require that fundamental understandings be developed.

Time-dependent strength degradation of granite

2009 ◽  
Vol 46 (7) ◽  
pp. 1103-1114 ◽  
Author(s):  
Q.X. Lin ◽  
Y.M. Liu ◽  
L.G. Tham ◽  
C.A. Tang ◽  
P.K.K. Lee ◽  
...  
Keyword(s):  
Strength Degradation ◽  
Time Dependent

Time-Dependent Reliability Model of Structures Under Different Stochastic Loads

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Hua-Ming Qian ◽  
Tudi Huang ◽  
Hong-Zhong Huang
Keyword(s):  
Continuous Time ◽  
Applied Load ◽  
Cumulative Effect ◽  
Random Variable ◽  
Strength Degradation ◽  
Time Dependent ◽  
Reliability Model ◽  
Reliability Models ◽  
Stochastic Loads ◽  
The Relationship

Abstract This paper proposes the time-dependent reliability model of structures under different stochastic loads based on the stress–strength interference (SSI) model and probabilistic statistical theory. First, the different stochastic loads mean that the loads are discrete, and that one applied load is from random variable and the other applied load may be from another random variable, and the cumulative effect and correlation are considered when they are applied for multiple times. Second, two different time-dependent reliability models, with and without considering strength degradation, are established in this paper. Meanwhile, the relationship between the discrete load frequency and time is described using Poisson process, and the time-dependent reliability model under continuous time is also provided. Finally, the proposed time-dependent reliability model of structures is validated with the Monte Carlo simulation (MCS), and the effectiveness of the proposed method is testified.

Age Softening Characteristics of Annealed 2-1/4Cr-1Mo Steel in the Temperature Range 424 to 704°C

1981 ◽  
Vol 103 (1) ◽  
pp. 62-70
Author(s):  
P. P. Pizzo ◽  
G. L. Mandurrago
Keyword(s):  
Thermal Aging ◽  
Strength Degradation ◽  
Time Dependent ◽  
Commercial Alloy ◽  
Short Term ◽  
Flow Strength ◽  
Temperature Range ◽  
Heat Treated ◽  
Proeutectoid Ferrite ◽  
Service Regime

The short-term age softening characteristics of isothermal annealed and post weld heat treated 2-1/4Cr-1Mo steel have been investigated over the temperature range 454 to 727°C (850 to 1340°F). Significant degradation in flow strength is observed for times and temperatures within the current service regime of the commercial alloy. Age softening is atypical: flow strength degradation is most rapid at some intermediate temperature. The reduction in flow strength is greatest, and occurs most rapidly, at 575°C (1067°F). The strength degradation is attributed to time-dependent redistribution of molybdenum within the proeutectoid ferrite. It is predicted that thermal aging in the temperature range 427 to 593°C (800 to 1000°F) will result in similar strength decrements for annealed 2-1/4Cr-1Mo steel regardless of prior thermal history above 704°C (1300°F).

scholarly journals A time-dependent probabilistic fatigue analysis method considering stochastic loadings and strength degradation

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878556 ◽  
Author(s):  
Chunbo Su ◽  
Shui Yu ◽  
Zhonglai Wang ◽  
Zafar Tayyab
Keyword(s):  
Density Estimation ◽  
Failure Probability ◽  
Safety Margin ◽  
Estimation Method ◽  
Kernel Density ◽  
Strength Degradation ◽  
Probability Density Functions ◽  
Time Dependent ◽  
Density Functions ◽  
Dependent Failure

This article proposes two strategies for time-dependent probabilistic fatigue analysis considering stochastic loadings and strength degradation based on the failure transformation and multi-dimensional kernel density estimation method. The time-dependent safety margin function is first established to describe the limit state of the time-dependent failure probability for mechatronics equipment with stochastic loadings and strength degradation. Considering the effective safety margin points and the corresponding number of the load cycles, two strategies for transforming the time-dependent failure probability calculation to the static reliability calculation are then proposed. Multi-dimensional kernel density estimation method is finally employed to build the probability density functions and the reliability is estimated based on the probability density functions. An engineering case of a filtering gear reducer is presented to validate the effectiveness of the proposed methods both in computational efficiency and accuracy.

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