A method to assess reliability and life of selected aircraft components suffering from cumulative effect of destructive processes – an outline

2012 ◽  
Vol 30 (1) ◽  
pp. 91-108
Author(s):  
Henryk Tomaszek ◽  
Ryszard Kaleta ◽  
Mariusz Zieja
Keyword(s):  
Boundary Condition ◽  
Mathematical Models ◽  
Cumulative Effect ◽  
Second Line ◽  
Diagnostic Parameter ◽  
Structural Components ◽  
Diagnostic Parameters ◽  
Wear And Tear ◽  
The Moment ◽  
Destructive Processes

There are two main directions to be distinguished while investigating into the wear-and-tear processes going on within the aircraft’s structural components throughout the operational phase. The first one covers the efforts to explain the physics of the wear-and-tear processes whereas the second one has been intended to generate mathematical models that describe the way how the effects of the wear-and-tear processes accumulate and provoke changes in values of diagnostic parameters. This paper represents the second line of interest and covers the model that formalises the process of the accumulation of effects of the aircraft component’s wear-and-tear up to the moment the permissible boundary condition is reached. What has been used in the below-presented model is the distribution of time of the aircraft structure in service up to the moment the diagnostic parameter reaches the boundary condition. Finally, a numerical example has been presented.

scholarly journals Motion fluency effects on object preference is limited to learned context

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244110
Author(s):  
Jonathan Charles Flavell ◽  
Bryony McKean
Keyword(s):  
Boundary Condition ◽  
Original Work ◽  
Object Motion ◽  
Preference Change ◽  
Behavioural Interventions ◽  
Stimulus Choice ◽  
Critical Boundary ◽  
The Moment ◽  
Do So ◽  
Object Preference

Recently, Flavell et al. (2019) demonstrated that an object’s motion fluency (how smoothly and predictably it moves) influences liking of the object itself. Though the authors demonstrated learning of object-motion associations, participants only preferred fluently associated objects over disfluently associated objects when ratings followed a moving presentation but not a stationary presentation. In the presented experiment, we tested the possibility that this apparent failure of associative learning / evaluative conditioning was due to stimulus choice. To do so we replicate part of the original work but change the ‘naturally stationary’ household object stimuli with winged insects which move in a similar way to the original motions. Though these more ecologically valid stimuli should have facilitated object to motion associations, we again found that preference effects were only apparent following moving presentations. These results confirm the potential of motion fluency for ‘in the moment’ preference change, and they demonstrate a critical boundary condition that should be considered when attempting to generalise fluency effects across contexts such as in advertising or behavioural interventions.

Low endurance fatigue behaviour of mild steel beams in reversed bending

1966 ◽  
Vol 1 (3) ◽  
pp. 239-247 ◽  
Author(s):  
R Royles
Keyword(s):  
Mild Steel ◽  
Fatigue Resistance ◽  
Fatigue Behaviour ◽  
Steel Beams ◽  
Cyclic Heating ◽  
Structural Components ◽  
Material Behaviour ◽  
Pure Bending ◽  
Axial Extension ◽  
The Moment

The behaviour of mild steel under conditions of reversed bending in the inelastic range at relatively slow rates of cycling, falls into the category of the low endurance fatigue problem in metals, where failures occur within 105 cycles. This investigation is concerned with an examination of material behaviour in reversed bending (i.e. pure bending) at three frequencies——1, 10 and 100 c/min——and strain ranges in the region from 0.5-12 per cent. Axial extension assumed some significance during the tests at the larger strain ranges, as did cyclic heating at the higher frequency. Some adjustments are made to take account of the effects of axial extension in the tests at the two lower frequencies. A moment-curvature relationship for the material in a cyclic state is established along with a fatigue resistance law for the range of deformations considered; the former being restricted to cyclic operations in the range from 1 to 10 c/min. An indication is given, supported by some experimental evidence, of how the moment-curvature relationship and fatigue resistance law can be used to predict the behaviour of mild steel structural components subjected to the type of loading under consideration.

scholarly journals Technical and Economic Assessment of the Condition of Fixed Assets and the Criterion of the Validity of Recovery Investments

2020 ◽  
Vol 30 (1) ◽  
pp. 89-99
Author(s):  
Tatyana Ogorodnikova ◽  
Aleksei Solomein ◽  
Vladimir Orlov ◽  
Irina Shipunova
Keyword(s):  
Economic Assessment ◽  
Negative Consequences ◽  
Fixed Assets ◽  
Return On Capital ◽  
Wear And Tear ◽  
Methodological Approaches ◽  
The Interest Rate ◽  
The Moment ◽  
Effective Use ◽  
The Relationship

The article analyzes the methodology for calculating depreciation and assessing the condition of fixed assets. The absence of conditionality of the period of use and depreciation allowance of fixed assets due to their physical wear and tear in specific production conditions is revealed. Thus, it is concluded that the theoretical estimates of the condition of fixed assets do not correspond to their actual physical wear and tear. The internal contradictions of the indicator of return on capital are investigated, its inconsistency with the essence of production is revealed. The absence of a criterion for the need for renovation investment is mentioned as one of the negative consequences of the existing methodological approaches to assessing the condition of fixed assets. In order to overcome the shortcomings and negative consequences of the methodology for assessing the condition of fixed assets, the relationship between the depreciation coefficient, the technical accelerator and the integral indicator of physical wear is revealed. To characterize the dependence of the volume of production and operating costs on the physical depreciation of fixed assets, a conversion factor is substantiated and introduced. Formal models of indicators of production and return on capital are presented. They reflect partial and generalizing coefficient of conversion of fixed assets as well as the interest rate and the level of inflation. The moment of zero efficiency of fixed assets is substantiated as a criterion of necessity and timeliness of renovation investments. In addition, the concept of the period of their effective use is introduced.

scholarly journals Information Contents of a Signal at Repeated Positioning Measurements of the Coordinate Measuring Machine (CMM) by Laser Interferometer

2016 ◽  
Vol 16 (5) ◽  
pp. 273-279 ◽  
Author(s):  
Tomáš Stejskal ◽  
Tatiana Kelemenová ◽  
Miroslav Dovica ◽  
Peter Demeč ◽  
Miroslav Štofa
Keyword(s):  
Permanent Deformation ◽  
Coordinate Measuring Machine ◽  
Repeated Measurements ◽  
Time Interval ◽  
Passive Resistance ◽  
Complex Information ◽  
Wear And Tear ◽  
Measuring Machine ◽  
The Moment ◽  
Spatial Positioning

Abstract The input of this paper lies in displaying possibilities how to determine the condition of a coordinate measuring machine (CMM) based on a large number of repeated measurements. The number of repeated measurements exceeds common requirements for determining positioning accuracy. The total offset in the accuracy of spatial positioning consists of partial inaccuracies of individual axes. 6 basic errors may be defined at each axis. In a triaxial set, that translates into 18 errors, to which an offset from the perpendicularity between the axial pairs must be added. Therefore, the combined number of errors in a single position is 21. These errors are systemic and stem from the machine’s geometry. In addition, there are accidental errors to account for as well. Accidental errors can be attributed to vibrations, mass inertness, passive resistance, and in part to fluctuations in temperature. A peculiar set of systemic errors are time-varying errors. The nature of those errors may be reversible, for instance if they result from influence of temperature or elastic deformation. They can be also irreversible, for example as a result of wear and tear or line clogging, due to loosened connection or permanent deformation of a part post collision. A demonstration of thermal equalizing of the machine’s parts may also be observed in case of failure to adhere to a sufficient time interval from the moment the air-conditioning is turned on. Repeated measurements done on a selected axis with linear interferometer can provide complex information on the CMM condition and also on the machine’s interaction with the given technical environment.

scholarly journals HYDROPHOBIZATION OF FINE CHALK

2021 ◽  
Vol 6 (6) ◽  
pp. 63-70
Author(s):  
Y. Krivenko ◽  
A. Vezentsev
Keyword(s):  
Calcium Carbonate ◽  
Carboxylic Acids ◽  
Granulometric Composition ◽  
Gas Adsorption ◽  
Cumulative Effect ◽  
Differential Distribution ◽  
Technical Literature ◽  
Grinding Method ◽  
Materials Used ◽  
The Moment

Natural fine chalk (calcium carbonate) is widely used functional filler for composite materials used in many industries. The development of in-depth studies of the physicochemical properties of hydrophobic chalk contributes to the expansion of its application. The analysis of scientific and technical literature has shown that at the moment there are no studies of the parameters of the porous structure and textural parameters of natural chalk of various granulometric composition, especially superficially treated (hydrophobized) with fatty carboxylic acids. Carboxylic acids of C17 to C20 fractions are practically applied for hydrophobization of calcium carbonate that is conditioned by presence of these acids with enough long hydrocarbon chains and reactive carboxyl group. The treatment of chalk with hydrophobizing additive gives it the following advantages over untreated chalk: prevention of moisture accumulation, absence of caking and improvement of technological properties (flowability, compatibility with polymer and others). The paper presents the results of chemical and mineralogical analyses of natural chalk from the Sheinsky deposit, data on the differential distribution of particles, the degree of hydrophobicity, and the study of the textural characteristics of natural and hydrophobized fine chalk. The influence of the grinding method on the granulometric composition is evaluated and the cumulative effect of the grinding method and hydrophobization on the texture characteristics of chalk is revealed. It is established that the surface treatment of chalk particles with fatty acids (C18 content not less than 65 wt%) affects the process of nitrogen gas adsorption

scholarly journals Influence of the Moment in Mathematical Models for Open Systems

2021 ◽  
Vol 16 ◽  
pp. 250-260
Author(s):  
Evelina Prozorova
Keyword(s):  
Mathematical Models ◽  
Stress Tensor ◽  
Open Systems ◽  
Three Dimensional ◽  
Theory Of Elasticity ◽  
Collective Effects ◽  
Physical Parameters ◽  
Potential Flows ◽  
The Moment ◽  
Definition Of

Article is proposed, built taking into account the influence of the angular momentum (force) in mathematical models of open mechanics. The speeds of various processes at the time of writing the equations were relatively small compared to modern ones. Theories have generally been developed for closed systems. As a result, in continuum mechanics, the theory developed for potential flows was expanded on flows with significant gradients of physical parameters without taking into account the combined action of force and moment. The paper substantiates the vector definition of pressure and the no symmetry of the stress tensor based on consideration of potential flows and on the basis of kinetic theory. It is proved that for structureless particles the symmetry condition for the stress tensor is one of the possible conditions for closing the system of equations. The influence of the moment is also traced in the formation of fluctuations in a liquid and in a plasma in the study of Brownian motion, Landau damping, and in the formation of nanostructures. The nature of some effects in nanostructures is discussed. The action of the moment leads to three-dimensional effects even for initially flat structures. It is confirmed that the action of the moment of force is the main source of the collective effects observed in nature. Examples of solving problems of the theory of elasticity are given.

scholarly journals Method for the diagnosis of high-voltage dielectric elements during operation based on dynamic registration of electromagnetic radiation

2020 ◽  
Vol 216 ◽  
pp. 01061
Author(s):  
Dmitry Ivanov ◽  
Tatyana Galieva ◽  
Marat Sadykov ◽  
Alexander Golenischev-Kutuzov ◽  
Anatoly Naumov
Keyword(s):  
High Voltage ◽  
Residual Life ◽  
Technical Condition ◽  
Time Of Arrival ◽  
Frequency Method ◽  
Diagnostic Parameters ◽  
Reliable Assessment ◽  
The Difference ◽  
The Moment

Complex remote monitoring and the developed non-contact diagnostic device (NDD) allow monitoring the technical condition and revealing the residual life of high-voltage dielectric elements. It is based on non-contact remote periodic measurement of a set of diagnostic parameters (characteristics of electrical discharges emitted by insulators during operation) necessary for a reliable assessment of the operating state of high-voltage dielectric equipment at the moment of operation and determination of its residual life. NDDs are installed on each phase conductor and used to measure diagnostic parameters, followed by computer processing of the accumulated information signals. An analysis of the set of necessary diagnostic parameters makes it possible to form a conclusion on the degree of performance of dielectric elements. The paper considers a method for detecting defective high-voltage insulators using the developed non-contact diagnostic devices by the radio frequency method and assessing the difference in time of arrival of a partial discharge signal.

scholarly journals Analysis of mathematical models for calculating following intervals in main flows the prevailing road conditions in the Russian Federation

2020 ◽  
Vol 17 (6) ◽  
pp. 714-725
Author(s):  
A. Yu. Mikhailov ◽  
E. L. Popova
Keyword(s):  
Mathematical Models ◽  
Russian Federation ◽  
Queue Length ◽  
European Part ◽  
Current Level ◽  
The Russian Federation ◽  
1960S And 1970S ◽  
The 1960S ◽  
The Moment ◽  
Market Relations

Introduction. This paper presents the results of a study on the methods for calculating the capacity of level crossings. The purpose of writing this research paper is determine the best methodology for calculating the intervals in the main flows for the prevailing road conditions in the Russian Federation, that a new methodology to calculate capacity adapted to domestic road conditions would be developed in the future.Materials and methods. In recent decades of market relations in the Russian Federation, one can note a rapid increase in motorization in human settlements. The number in 550 vehicles per 1000 people in domestic entities is expected to have been increasde by 2025, which is significantly higher than the current level in European part of the Russian Federation. It is important to note that when the number of vehiclec is increasing, which level is about 80%, it is essential to increase road crossings capacity. Results. At the moment the methodology for calculating capacity and queue length is the same. It should be noted that the current models are not properly described in the domestic studies, but the calculations were made using models developed in the 1960s and 1970s.

scholarly journals Ground base deformation by circular plate peculiarities

2018 ◽  
Vol 230 ◽  
pp. 02040
Author(s):  
Mykola Zotsenko ◽  
Yuriy Vynnykov ◽  
Iryna Lartseva ◽  
Svitlana Sivitska
Keyword(s):  
Boundary Condition ◽  
Bearing Capacity ◽  
Circular Plate ◽  
Compacted Soil ◽  
Loaded Plate ◽  
Elastic Core ◽  
Boundary Equilibrium ◽  
Area Of Influence ◽  
The Moment

It is established that at the moment of the onset of the boundary equilibrium of the base under a central loaded plate, an elastic core is formed in the form of a cone, all particles move along with the plate progressively down. In this case, within the limits of the “area of influence” the boundary condition of the base is violated by protrusion or consolidation of soils. The volume of the “area of influence” is determined by the height of the elastic core, from which its diameter is calculated. Experiments using conical tips were made and the height of the elastic core was determined and the diameter of the “area of influence” was determined. For creation at penetration and probing friction of soil on a ground the conic tip is executed rough with cylindrical stages. Under the steps of the tip, formed areas of compacted soil, moving along with it, creating a so-called “ground shirt” in the form of a cone with a creature at an angle α to the vertical. The obtained data allowed specifying coefficients of bearing capacity of soils, which are used in construction norms.

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