Application of the Acoustic Emission Method for Estimating the Residual Life of Elastic Elements at the Stage of Preparing a Product for Operation

The article discusses the experimental substantiation of predicting the operational properties of elastic elements by the acoustic emission (AE) method, as well as the use of the non-destructive method of acoustic emission as an element of digital certification of critical mechanical and instrument engineering products.

Integrated modelling method of bonding strength and residual life prediction for selective repair structure of aluminium alloy

To accurately describe and predict the overall strength and residual life of selective repair bonded structures, an integrated simulation model of crack propagation including bonding strength is established. Based on two methods, an integrated simulation model including a cohesive zone method model for predicting the residual life of a selective repair structure is established. By comparing the computational efficiency and accuracy of both the stress intensity factor and residual life of selective repair structures using different calculation methods, the modelling scheme is optimised. Based on this optimised scheme, the effect of adhesive thickness on the stress intensity factor and residual life of the repair structure is analysed. FM94 adhesive measuring 0.2–0.4 mm thickness is used to decrease the stress intensity factor and improve the remaining life such that material utilisation efficiency is guaranteed.

Method for assessing the state and residual life of the insulation based on analysis of the time of discharge of the capacity of electric cables

As of today, the problem of the lack of non-destructive methods for assessing the state and determining the residual life of the insulation of electrical cables is relevant for cable lines in operation, and especially for lines that have exhausted their service life. The research presented in the framework of this article is aimed at creating a non-destructive technique for assessing the state and residual life of electrical cables insulation. The study was carried out using computer simulation methods and using the basic theoretical laws of physics and electrical engineering. A method for assessing the condition and residual life of electrical cable insulation has been developed, which is based on the analysis of the discharge time of the cable capacity. The applicability of the method is determined, instructions are given on its applicability and the analysis of the output data. The obtained results can be used by power grid companies and industrial enterprises to analyze the state of the insulation of electrical cables.

Fisher consistent estimation of regression parameter in the proportional mean residual life model with frailty

In the article, we consider the Fisher consistent estimation of the regression parameters in the proportional mean residual life model with arbitrary frailty. It is discussed that conventional estimation procedures, such as the maximum likelihood estimation or Cox’s approach, which are employed in common regression models, may also yield consistent inference in the extended models.

COMPUTATIONAL AND EXPERIMENTAL METHOD FOR ESTIMATING THE RESIDUAL LIFE OF GEARS BASED ON VIBRATION MONITORING DATA

A computational and experimental method for estimating the residual life of gears in the inter-repair period is proposed. The method is based on the main provisions of the theory of vibration-pulse diagnostics of spur gears, developed at the OIM of the National Academy of Sciences of Belarus. The main performance criteria are the contact and bending endurance of the teeth. Accounting for changes in the value of the coefficient of internal dynamic load in the gearing during the operation of gears is carried out on the basis of vibration analysis during their vibration monitoring. The proposed method makes it possible to estimate the residual life of the gear mechanism at any stage of operation, providing the opportunity to organize the transition from planned preventive maintenance of machines to maintenance according to the actual condition. An example of estimating the residual life of a gear pair that limits the reliability of a two-row planetary gear motor-wheel of a heavy-duty dump truck is given. Keywords: gear transmission; vibration monitoring; residual life; inter-repair period; internal dynamic load in engagement

Analysis of methods and methods of diagnosing internal combustion engines by non-assembly control methods

The question of interaction of schemes of diagnostics of engines by methods of non-disassembled control is considered, the analysis of existing methods is executed, and the use of the complex approaches increasing reliability of work of engines is offered. Methods of non-detachable diagnostics with modeling of deregulation of engine systems during operation and diagnosing the initial stages of structural and functional malfunctions are analyzed. The analysis allowed to determine the direct diagnostic parameters that unambiguously characterize the state of the object and indirect, associated with direct functional dependencies, and identify the most effective, in terms of determining correlations - direct diagnostic methods, which include, for example, indication of the working process in the engine cylinder. A relatively simple scheme of measuring and determining signals from several diagnostic elements simultaneously is proposed, from which we can conclude that information from one measurement channel can comprehensively characterize the technical condition of several elements of engine mechanisms or systems: vibration method, acoustic method, gas chromatography methods, indirect indication by determining the stress in the studs of the cylinder head, assessing the level of wear of parts on the metal content in the engine oil, as well as diagnosing the parameters of the uneven speed of the crankshaft. Analysis of methods and techniques for diagnosing internal combustion engines led to the conclusion that the method of diagnosing the uneven speed of the engine crankshaft is a promising direction in the development of methods of non-demountable diagnostics of internal combustion engines. residual life and monitor the technical condition of the engine.