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To present a method of interaction between flight loads that is applied to a probabilistic damage tolerance analysis in an acrobatic aircraft.

The uncertainties concerning material strength, initial crack size and loads in the aircraft are considered. We place special emphasis on stress distribution, using superposition criteria that distinguish between gust, maneuver and ground‐air‐ground loads. Gust load is generated form its power spectral density and modified using service load data (exceedance curves). Crack initiation time and propagation time are considered in calculating the service time.

A new and realistic method of interaction between loads during acrobatic flight is proposed. This method was compared with other methods in an example. The effects of the interaction criteria are related to the influence between loads (stress levels and frequency).

In commercial aircraft, maneuver loads have a lower influence than gust loads, and the mission concept is the correct approach. Training aircraft have the opposite king of behavior and the proposed superposition method is shown to be better approach. This method would have more pronounced effects in aircraft types with behaviors between commercial and training (for example, amphibious aircraft).

Fatigue of aircraft structures has become a major subject for research in the past ten years and the importance of establishing safe lifetimes for operation of aircraft or for replaceable structural components is now recognized. Some major contributions have been made to the knowledge of this subject, including methods of life assessment, determination of the fatigue resistance of several types of complete aircraft wing structure by laboratory test and some more fundamental studies of fatigue. The fatigue problem is considerably better understood than it was ten years ago and it can now be said with certainty where the most serious gaps lie. Information on two of these topics—namely, scatter, and the effect of random loading sequences—is being sought in the research programmes now proceeding at the Aeronautical Research Laboratories. Because of the vastness of the field a plea is made for greater inter‐change of information on the results of fatigue tests in all countries.

This review aims to give a critical view of the wheel/rail high frequency vibration-induced vibration fatigue in railway bogie.

Vibration fatigue of railway bogie arising from the wheel/rail high frequency vibration has become the main concern of railway operators. Previous reviews usually focused on the formation mechanism of wheel/rail high frequency vibration. This paper thus gives a critical review of the vibration fatigue of railway bogie owing to the short-pitch irregularities-induced high frequency vibration, including a brief introduction of short-pitch irregularities, associated high frequency vibration in railway bogie, typical vibration fatigue failure cases of railway bogie and methodologies used for the assessment of vibration fatigue and research gaps.

The results showed that the resulting excitation frequencies of short-pitch irregularity vary substantially due to different track types and formation mechanisms. The axle box-mounted components are much more vulnerable to vibration fatigue compared with other components. The wheel polygonal wear and rail corrugation-induced high frequency vibration is the main driving force of fatigue failure, and the fatigue crack usually initiates from the defect of the weld seam. Vibration spectrum for attachments of railway bogie defined in the standard underestimates the vibration level arising from the short-pitch irregularities. The current investigations on vibration fatigue mainly focus on the methods to improve the accuracy of fatigue damage assessment, and a systematical design method for vibration fatigue remains a huge gap to improve the survival probability when the rail vehicle is subjected to vibration fatigue.

The research can facilitate the development of a new methodology to improve the fatigue life of railway vehicles when subjected to wheel/rail high frequency vibration.

IN aircraft construction, until about fifteen years ago, the customary static method of stressing generally also provided for an adequate fatigue strength. This does not now apply for various reasons (e.g. increased flight speeds, use of high‐strength materials with changed fatigue properties). It is, therefore, necessary to establish design rules which take account of more recent knowledge; which variables are to be specially considered, and what their importance is in a particular case, becomes clear from fatigue tests which, to a considerable extent, cater for the peculiar loading conditions of flight (service endurance tests or programme‐loading tests). The principle of these tests was established in the DVL (1938 to 1941) and it is now in general use in automobile design for determining the relation between fatigue strength and endurance (life function) as in many cases of service failures a very good agreement with these tests can be observed.

Aero-engine components endure combined high and low cycle fatigue (CCF) loading during service, which has attracted more research attention in recent years. This study aims to construct a new framework for the prediction of probabilistic fatigue life and reliability evaluation of an aero-engine turbine shaft under CCF loading if considering the material uncertainty.

To study the CCF failure of the aero-engine turbine shaft, a CCF test is carried out. An improved damage accumulation model is first introduced to predict the CCF life and present high prediction accuracy in the CCF loading situation based on the test. Then, the probabilistic fatigue life of the turbine shaft is predicted based on the finite element analysis and Monte Carlo analysis, where the material uncertainty is taken into account. At last, the reliability evaluation of the turbine shaft is conducted by stress-strength interference models based on an improved damage accumulation model.

The results indicate that predictions agree well with the tested data. The improved damage accumulation model can accurately predict the CCF life because of interaction damage between low cycle fatigue loading and high cycle fatigue loading. As a result, a framework is available for accurate probabilistic fatigue life prediction and reliability evaluation.

The proposed framework and the presented testing in this study show high efficiency on probabilistic CCF fatigue life prediction and can provide technical support for fatigue optimization of the turbine shaft.

The novelty of this work is that CCF loading and material uncertainty are considered in probabilistic fatigue life prediction.

This preliminary investigation has shown that the programme load method of testing provides more useful information than single load level tests enabling a more reliable estimate of a structural joint fatigue life to be obtained.

This paper aims to develop a dynamic two-sided stable matching method based on preference information of the matching objects in uncertain environments, so as to solve the matching problem of cloud manufacturing tasks and services with load balancing.

For dynamic two-sided matching, due to the complexity of social environment and the limitation of human cognition, hesitation and fuzziness always exist in the process of multi-criteria assessment. First, in order to obtain the accurate preference information of each matching object, uncertain linguistic variables, uncertain preference ordinal and incomplete complementary matrices are used to evaluate multi-criteria preference information. This process is undertaken by considering the probability of each possible matching pair. Second, the preference information at different times is integrated by using the time-series weight to obtain the comprehensive satisfaction degree matrices of the matching objects. Further, the load adjustment parameter is used to increase the satisfaction degree of the matching objects. Afterward, a dynamic two-sided stable matching optimization model is constructed by considering stable matching conditions. The model aims to maximize the satisfaction degree and minimizes the difference in the satisfaction degree of matching objects. The optimal stable matching results can be obtained by solving the optimization model. Finally, a numerical example and comparative analysis are presented to demonstrate the characteristics of the proposed method.

Uncertain linguistic variables, uncertain preference orders and incomplete complementary matrices are used to describe multi-criteria preference information of the matching objects in uncertain environments. A dynamic two-sided stable matching method is proposed, based on which a DTSMDM (dynamic two-sided matching decision-making) model of cloud manufacturing with load balancing can be constructed. The study proved that the authors can use the proposed method to obtain stable matching pairs and higher matching objective value through comparative analysis and the sensitivity analysis.

A new method for the two-sided matching decision-making problem of cloud manufacturing with load balancing is proposed in this paper, which allows the matching objects to elicit language evaluation under uncertain environment more flexibly to implement dynamic two-sided matching based on preference information at different times. This method is suitable for dealing with a variety of TSMDM (two-sided matching decision-making) problems.

This review paper seeks to enhance knowledge of how pre-loading affects reinforced concrete (RC) beams under fire. It investigates key factors like deflection and load capacity to understand pre-loading's role in replicating RC beams' actual responses to fire, aiming to improve fire testing protocols and structural fire engineering design.

This review systematically aggregates data from existing literature on the fire response of RC beams, comparing scenarios with (WP) and without pre-loading (WOP). Through statistical tools like the two-tailed t-test and Mann–Whitney U-test, it assesses deflection extremes. The study further examines structural responses, including flexural and shear behavior, ultimate load capacity, post-yield behavior, stiffness degradation and failure modes. The approach concludes with a statistical forecast of ideal pre-load levels to elevate experimental precision and enhance fire safety standards.

The review concludes that pre-loading profoundly affects the fire response of RC beams, suggesting a 35%–65% structural capacity range for realistic simulations. The review also recommended the initial crack load as an alternative metric for determining the pre-loading impact. Crucially, it highlights that pre-loading not only influences the fire response but also significantly alters the overall structural behavior of the RC beams.

The review advances structural fire engineering with an in-depth analysis of pre-loading's impact on RC beams during fire exposure, establishing a validated pre-load range through thorough statistical analysis and examination of previous research. It refines experimental methodologies and structural design accuracy, ultimately bolstering fire safety protocols.

Quality problems in the service organization are the result of the mismatch between prior expectation and perceived quality of the service. Each organization will attempt to determine the requirements of its customers and translate these requirements into product and delivery process specifications. This paper examines a particular electric company (SCECO‐East), a typical service provider in Saudi Arabia, in which service quality is a distinguishing feature of primary importance. It describes a detailed survey and analysis in the light of the model put forward by Parasuraman et al. It utilizes SERVQUAL for measuring customers’ perceptions of service quality. The study revealed that SCECO‐East scored high in tangibles dimension but low in features of responsiveness and reliability. In addition, while the performance of SCECO‐East was acceptable to all customer categories, service quality was perceived differently by various types of customers, with reinforcement and commercial customers awarding SCECO‐East even lower ratings than other customers did.