Strength Reliability Research Articles

Estimation of Reliability in a Multicomponent Stress–Strength Model for a General Class of Inverted Exponentiated Distributions Under Progressive Censoring

We consider estimation of the multicomponent stress–strength reliability for a general class of inverted exponentiated distributions under progressive type-II censoring. We assume that both stress and strength variables follow this general class of distributions with a common parameter. Different point and interval estimates for the reliability of this system are obtained by using maximum likelihood and Bayesian approaches when the common parameter is known and unknown. The uniformly minimum variance unbiased estimate and exact Bayes estimate under the squared error loss function are derived when the common parameter is known. Bayes estimates are also obtained by using Lindley, Tierney–Kadane and Markov chain Monte Carlo methods. The asymptotic confidence and highest posterior density credible intervals are constructed. Proposed methods are compared numerically using Monte Carlo simulations. Finally, a progressively censored real data set is analyzed for illustration purposes.

Reliability analysis of multicomponent stress–strength reliability from a bathtub-shaped distribution

In this paper, inference for a multicomponent stress–strength model is studied. When latent strength and stress random variables follow a bathtub-shaped distribution and the failure times are Type-II censored, the maximum likelihood estimate of the multicomponent stress–strength reliability (MSR) is established when there are common strength and stress parameters. Approximate confidence interval is also constructed by using the asymptotic distribution theory and delta method. Furthermore, another alternative generalized point and confidence interval estimators for the MSR are constructed based on pivotal quantities. Moreover, the likelihood and the pivotal quantities-based estimates for the MSR are also provided under unequal strength and stress parameter case. To compare the equivalence of the stress and strength parameters, the likelihood ratio test for hypothesis of interest is also provided. Finally, simulation studies and a real data example are given for illustration.

Development of Mathematical Models to Optimize Weld Penetration Area of Mild Steel in Gas Tungsten Arc Welding

Tungsten Inert Gas (TIG) weld quality and mechanical properties are systematically structured by the bead width, reinforcement and penetration size. This study has developed a mathematical model using the second order quadratic polynomial model to select the best setting for the process parameters to produce the maximum penetration area in TIG welding.The set of experiment samples was produced from mild steel plates guided by a central composite design experimental plan. The results obtained revealed that the second order quadratic polynomial equation is the best fit model that can accurately explain the relationship between the input and the output parameters. The results possessed good statistical sufficiency, having a very good strength for predicting the target response. The prediction strength and models reliability factor are in reasonable agreement with each other, the surface plots showed the combined interaction of input parameters on the response, and the ANOVA results revealed that the penetration area is very sensitive to the current parameter. The mathematical models developed have a high goodness of fit, adequate signal,strength which can explain and predict the penetration area

Investigation of shear strength correlations and reliability assessments of sandwich structures by kriging method

Steel-concrete-steel (SCS) sandwich composite structure with corrugated-strip connectors (CSC) is the promising structure which is applied in offshore and building structures. The behavior prediction of shear connections is of major importance in SCS structures. The present study evaluated the existing shear strength correlations of SCS sandwich structures exploiting experimental data and Finite Element Analysis (FEA). The considered system is a double steel skin sandwich structure with CSC (DSCS). Due to the limitation of the literature regarding CSC development, some new correlations were proposed and studied relying on several FEA results through the Genetic Programming method. The accuracy of the estimated shear strength predicted by the existing and proposed equations was evaluated using the FEA data and push-out test results. The FE models were verified through experimental data. Moreover, the correlations were investigated based on reliability assessment due to the high importance of the reliability analysis of such structures. Given that high accuracy in estimating the shear strength fails to necessarily lead to acceptable results in structural reliability analysis, the reliability of the existing and proposed equations was evaluated using the Kriging model by considering experimental data. This meta-model could predict accurate values with a limited number of initial training samples.

Structural health monitoring of metal-to-glass\u2013ceramics penetration during thermal cycling aging using femto-laser inscribed FBG sensors

Maintaining the mechanical strength and hermetic reliability of metal-to-glass–ceramics electrical penetration assembly (MTGC-EPA) is a key concern for ensuring the pressure boundaries of nuclear power plants. The transient temperature change caused by power adjusting or accidents in High Temperature Reactor Pebble-bed Modules may affect the structural health of sealing glass–ceramics, even leading to radiation leakage. To evaluate whether the function could survive temperature variations during the service life, thermal cycling aging experiments were imposed to MTGC-EPA. A grating length-mismatched sensing method to monitor the residual strain, an important factor of glass–ceramics structural health, was demonstrated in real-time by femto-laser inscribed fiber Bragg grating (FBG) sensor during the curing process and thermal cycling aging. Scanning electron microscope (SEM) and leakage rate tests were carried out to obtain the comparisons of microstructure and hermeticity before and after the thermal cycling. The residual strain showed a slight growth trend with thermal cycles repetition and it persisted a high value (~ 4,000 με) reflected by both Bragg wavelength shift and spectrum shape. The grating length mismatched single FBG embedded in glass–ceramics was feasible to demodulate the temperature and strain simultaneously, and the embedded FBG method achieved the structural health monitoring of MTGC-EPA during thermal cycling aging with good accuracy and reliability. Combining with the results of SEM and leakage rate detecting, the structural health of MTGC-EPA was demonstrated to be capable to endure the severe thermal conditions in nuclear reactors.

Bayesian estimation of stress–strength reliability for two-parameter bathtub-shaped lifetime distribution based on maximum ranked set sampling with unequal samples

Bayesian estimation and credible interval of stress–strength reliability for two-parameter bathtub-shaped lifetime (TPBL) distribution are considered based on simple random sampling (SRS), ranked set sampling (RSS) and maximum ranked set sampling with unequal samples (MRSSU). Monte Carlo simulations are used to compare the performances of different proposed methods for Bayesian inferences on R. The results of simulation show that the estimator of the stress–strength reliability based on MRSSU and RSS are more efficient than SRS. Also, we make a comparison between the performance of the proposed methods in this paper and Tarvirdizade and Ahmadpour's [Estimation of the stress–strength reliability for the two-parameter bathtub-shaped lifetime distribution based on upper record values. Stat Methodol. 2016;31:58–72] method, which is based on upper record values. Finally, a real data set has been analyzed for illustrative purposes.

Truncated Rayleigh Pareto Distribution

In this paper, we introduced a new distribution which is the truncated Rayleigh Pareto distribution of a variable, and some useful functions, and some mathematical and statistical properties such as density function, the cumulative distribution function, limit function, reliability function, hazard function, stress - strength reliability, engineering arithmetic mean, mode and median, harmonic arithmetic mean, the rth moment about the mean and the origin, coefficients of variation, of kurtosis and Skewedness, order statistic, and some estimation methods.

Beta Inverted Lindley Distribution: Stress-Strength Reliability & Application

This research includes new probability distribution which is named beta inverted Lindley distribution. Some useful functions of the proposed distribution are derived. Important mathematical expansions are investigated. Statistical measures including; quantiles, moments, incomplete moments, Renyi and s entropies are acquired. Extra statistical properties such as mean deviations, central of tendency measures, coefficient of variation, coefficients of skewness and kurtosis are defined. The Bonferroni and Lorenz curves are conducted and the stress- strength reliability is computed. The maximum likelihood method is used to estimate parameters of beta inverted Lindley distribution. The importance and significance of the introduced model are applied through failure times data set. The main aim behind generalization is to make more flexibility to the distribution so that more data can be analyzed using the new distribution. The model parameters are estimated using maximum likelihood estimation and simulation study is applied. The importance of the presented distribution is illustrated by using real data set. According to the results; the BIL distribution fits better than BIE and IL distributions to the given data.

Reliability sensitivity analysis based on stress-strength model of bearing with random parameters.

On the basis of the stress-strength model of the ball bearing with random parameters, the reliability sensitivity of the raceway strength is examined. The basic parameters are regarded as random variables subject to normal distribution. The Latin hypercube sampling method is adopted to obtain the samples, which are brought into the bearing model to obtain the corresponding maximum orthogonal shear stress. The explicit expression of shear stress was obtained by genetic algorithm-back propagation neural network fitting, and the limit-state equation is established in combination with the yield limit of bearing materials. First, this study analyzes the sensitivity of the maximum shear stress with respect to various parameters and obtains the effect of parameters on shear stress at various rotational speeds. Then, based on the stress-strength state equation, the strength reliability is obtained by using the improved first-order second-moment method, which is verified by Monte Carlo simulation. Finally, the reliability sensitivity with respect to the mean and standard variance of random variables is analyzed. This research can provide theoretical guidance for the design, production, and use of bearings.

Rayleigh-Rayleigh Distribution: Properties and Applications

In this paper, a new compound distribution named Rayleigh-Rayleigh (Ra-Ra) is presented. Several structural statistical properties of new distribution containing explicit expressions for the r-th moments, characteristic function, quantile function, order statistics, Shannon and relative entropies, besides stress strength reliability were considered and studied. The unknown parameters of Ra-Ra distribution have been estimated under the maximum likelihood estimation method. Moreover, the Ra-Ra distribution is applied upon a simulation study and real data set in order to evaluate its utility and flexibility.

О ВЕРОЯТНОСТНОМ ОПРЕДЕЛЕНИИ НАДЕЖНОСТИ ОБЪЕКТА ТЕХНОСФЕРЫ ПРИ ОПАСНЫХ ВОЗДЕЙСТВИЯХ

The subject of research is the process associated with determining the reliability parameter of buildings (structures) for their further operation in the technological process, causing effects in the form of additional loads (explosions, fires, vibration processes). The solution of such problems is relevant for the buildings (structures) acquired (rented) by the owner for further operation in the production process, in the technology of which fire and explosion hazardous substances (materials) are handled, stored or processed. The purpose of the study is to develop an approach that allows one to determine the parameter of the reliability of a building (structure) for operation under additional loads. To determine the indicators of safe permissible states of buildings (structures), the use of various criterion characteristics included in the content of deterministic, statistical and probabilistic approaches is given. A feature of assessing the reliability of buildings (structures) for their operation under additional loads (explosions, fires, vibration processes) is to determine the indicator of a given margin of safety and its stability under possible realized impacts. To solve the problem, it is proposed to use a simplified assessment of the safety margin of a building (structure) in terms of yield strength (for steel elements) and strength (for base materials, load-bearing walls, partitions and ceilings) corresponding to the maximum permissible values for their destruction. A consistent theoretical description of the formulas is presented, which makes it possible to establish a relationship between the safety margin of a building (structure) and the probability of its destruction under the implemented influences. An innovative approach is described that allows solving problems of assessing the strength reliability of structural elements of buildings (structures), when it is important to obtain guaranteed characteristics of an indicator of a given safety margin, its resistance to possible realized influences (explosions, fires, vibration processes). The use of the material in order to determine the reliability indicators based on risks allows us to consider the calculated values of the safety margin of a building (structure), which meets the established requirements for assessing efficiency from the point of view of the theory and practice of operations research.

Оценка прочностной надежности магистрального газопровода с учетом фактических закономерностей распределения толщины стенки трубы

Оценка прочностной надежности магистрального газопровода с учетом фактических закономерностей распределения толщины стенки трубы

On the probability determination of the reliability of a technosphere object under hazardous influence

The use of various criteria characteristics included in the content of deterministic, statistical and probabilistic approaches is shown in this article for determination the indicators of safe permissible conditions of buildings (structures). A feature of assessing the reliability of buildings (structures) for their operation under additional loads (explosions, fires, vibration processes) is the determination of an indicator of a given safety margin and its stability under possible realized effects. The aim of the study is to develop an approach to determine the reliability indicator of a building (structure), for operation in conditions of additional loads. The subject of the study is the process associated with the determination of the reliability indicator of buildings (structures), for their further operation in the technological process, causing effects in the form of additional loads (explosions, fires, vibration processes). The solution to such problems is relevant for buildings (structures) that are acquired (leased) by the owner, for their further operation in the production process, in the technology of which fire and explosion hazardous substances (materials) are handled, stored or processed. To solve the tasks, it is proposed to use a simplified assessment of the safety margin of a building (structure) by yield strengths (for steel elements) and strength (for base materials, load-bearing walls, partitions and ceilings) corresponding to the maximum allowable values for their destruction. The article provides a consistent theoretical description of the formulas, which allows us to establish a relationship between the safety margin of a building (structure) and the probability of its destruction during realized impacts. An innovative approach is described that allows us to solve the problems of assessing the strength reliability of structural elements of buildings (structures), when it is important to be able to obtain guaranteed characteristics of a given safety factor, its resistance to possible realized impacts - explosions, fires, vibration processes. The use of the material, in order to determine reliability indicators based on risks, allows us to consider the calculated values of the safety margin of a building (structure), which meets the established requirements for evaluating effectiveness from the point of view of theory and practice of operations research.

Time-dependent stress–strength reliability models based on phase type distribution

In many of the real-life situations, the strength of a system and stress applied to it changes as time changes. In this paper, we consider time-dependent stress–strength reliability models subjected to random stresses at random cycles of time. Each run of the system causes a change in the strength of the system over time. We obtain the stress–strength reliability of the system at time t when the initial stress and initial strength of the system follow continuous phase type distribution and the time taken for completing a run, called the cycle time, is a random variable which is assumed to have exponential, gamma or Weibull distribution. Using simulated data sets we have studied the variation in stress–strength reliability at different time points corresponding to different sets of parameters of the model.

On Estimation of P(Y_1<X<Y_2 ) in Cased Inverse Kumaraswamy Distribution

This paper deals with the estimation of the stress strength reliability for a component which has a strength that is independent on opposite lower and upper bound stresses, when the stresses and strength follow Inverse Kumaraswamy Distribution. D estimation approaches were applied, namely the maximum likelihood, moment, and shrinkage methods. Monte Carlo simulation experiments were performed to compare the estimation methods based on the mean squared error criteria.

In vitro cyclic fatigue and hydrothermal aging lifetime assessment of yttria-stabilized zirconia dental ceramics

The in vitro lifetime assessment of dental zirconia has been the focus of researchers. This work mainly studied the cyclic fatigue lifetime in saliva and aging lifetime of three commercial zirconia dental materials: two kinds of 3 mol%-yttria stabilized zirconia ST(super-translucence) and MT(medium-translucence), in which MT contains a small amount of alumina; a 5 mol%-yttria stabilized zirconia TT(tooth-translucency). ST and MT materials have higher initial mechanical strength (flexural strength) and initial crack propagation threshold than TT materials, thus they have longer cycle fatigue lifetime, but TT has best aging resistance(no aging) in existing aging procedures. MT has a higher initial mechanical strength and better aging resistance than ST samples due to the influence of alumina at grain boundary, but has lower strength reliability. Finally the service lifetime of the three materials was evaluated, and some guidance for their use is provided.

Can Bayesian, confidence distribution and frequentist inference agree?

We discuss and characterise connections between frequentist, confidence distribution and objective Bayesian inference, when considering higher-order asymptotics, matching priors, and confidence distributions based on pivotal quantities. The focus is on testing precise or sharp null hypotheses on a scalar parameter of interest. Moreover, we illustrate that the application of these procedures requires little additional effort compared to the application of standard first-order theory. In this respect, using the R software, we indicate how to perform in practice the computation with three examples in the context of data from inter-laboratory studies, of the stress–strength reliability, and of a growth curve from dose–response data.

Topological optimization by designing structural elements of logging machine manipulators

The structures of manipulators of modern logging machines are subject to a wide variety of requirements related to the implementation of the functions of these machines, as well as the technology of manufacturing, operation and disposal of structures. The leading requirements are to ensure high strength and operational reliability under a wide range of loads, high and low temperatures. In this case, it is necessary to obtain the minimum metal consumption of the design product. Structural optimization, in particular, topological optimization, should be used when 9designing manipulators for logging machines. The use of topological optimization makes it possible by calculation to carry out the redistribution of material in the calculation area of the design product, taking into account the required conditions. The use of Altair Inspire 2018.3 software tools makes it possible to reduce the weight of the designed structural element of the hydraulic manipulator of the forestry machine by 39%. At the same time, acceptable indicators of tensile strength, deformation, and standard safety factors are provided.

Creating the knowledge base and data banks to justify the strength reliability of the pipeline transport system for oil and petroleum products

The paper outlines the scientific fundamentals for creating and applying the knowledge bases and the data banks in the design, construction and operation of pipeline transport systems. The analysis of knowledge is carried out, the main directions of knowledge base creation and its fundamentals are considered in terms of the pipeline transport of oil and petroleum products. The knowledge bases include both the existing system of scientifically validated proposals to the structure, classification, criteria, constitutive equations for design-and-experimental assessment of strength, stability, stiffness of the load-bearing elements of pipeline transport facilities, and further development of these proposals in terms of analyzing the operation life, reliability, and damage tolerance of the pipeline transport system, analysis of its protection against crisis and emergency situations. Data banks are considered as the initial information basis for the knowledge implementation at all stages of the pipeline transport system life cycle. It is concluded that the creation of the unified system of knowledge base and data banks is of significant scientific and practical importance for the further development of pipeline transport systems with regard to up-to-date requirements for ensuring and improving their strength, service life, reliability, damage tolerance, and safety of construction and operation.

Study on the main influencing factors of shear strength of nano-silver joints

This article investigates the factors affecting the shear strength of nano-silver joints. Experiments were performed under different sintering temperatures, pressures, and time, different sintered layer thicknesses, different shear rates, and shear temperatures, and the effects of various parameters on joint strength were obtained. It is found that the joint strength can be increased when the sintering temperature, pressure, time and shear rate are increased. The maximum shear strength of the interconnection bond is measured at room temperature 25 °C and 150 °C, and the gap is large. Increasing the temperature will reduce the bond strength Reliability is reduced. The effects of some of these parameters and particle size on joint strength were further studied and analyzed.