scholarly journals Analysis of the Frequency Interaction of the Turbine Block in the Stand for the Magnitude of the Error in Measuring the Turbine’s Power

2021 ◽  
Vol 11 (9) ◽  
pp. 4149
Author(s):  
Anton Petrochenkov ◽  
Aleksey Sal’nikov ◽  
Sergey Bochkarev ◽  
Pavel Ilyushin
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Load ◽  
Technical Condition ◽  
Power Measurement ◽  
Dynamic State ◽  
Diagnostic Model ◽  
Wave Processes ◽  
Stiffness Coefficients ◽  
Frequency Interaction ◽  
The Impact

An algorithm for constructing a dynamic analysis during the formation of a wave field of stand for testing turbines and the effect of the frequency interaction of the stand’s elements on the measurement of its magnitude is described. The research algorithm involves the use of theoretical solutions of nonlinear wave processes using linear oscillations, refined by experiments. The diagnostic model can determine the technical condition of the stand’s elements and also determine the causes of the discrepancies between the calculated and measured turbine power values. To clarify the stiffness coefficients between the stand’s elements, a modal analysis was used to obtain the range of their changes depending on the external dynamic load, which made it possible to assess the impact of changes in the frequency interaction conditions on the turbine power measurement at different test modes. The conditions for amplifying the amplitude of oscillations at their eigenfrequencies are obtained, and the value of the possible deviation of the expected power value at its measurement for specific modes of the turbine is calculated. The algorithm allows to estimate the dynamic state of the stand-in different research modes of turbines and give recommendations for reducing the level of frequency interaction.

Diagnostic Model of the Marine Propulsion System

2016 ◽  
Vol 817 ◽  
pp. 57-63 ◽  
Author(s):  
Marcin Kluczyk ◽  
Andrzej Grządziela ◽  
Tomislav Batur
Keyword(s):  
Technical Condition ◽  
Diagnostic Model ◽  
Technical Diagnostics ◽  
Marine Propulsion ◽  
Diagnostic Models ◽  
Energy Dissipated ◽  
High Degree ◽  
The Impact ◽  
Marine Propulsion System ◽  
Proper Analysis

Naval propulsion systems are characterized by a high degree of complexity within a single system and a large variation between the solutions applied to individual vessels. In this situation, issues relating to the comprehensive diagnostic is a serious problem. Diagnostics models are useful to made the this problem easier. It should be emphasized that it is impossible to develop a universal model correct for all types of vessels. The paper presents general guidelines for the creation of diagnostic models. The results of first stage of studies on diagnostic model covers unit equipped with a twin-engine twin-shaft drive system had been presented.Introduction Changes of technical state of the machine occur as a result of its response to changes in the energy emitted by them. If qualitative and quantitative parameters of this energy are known diagnostician after proper analysis is able to determine the technical condition of the machine. It can be concluded that the technical diagnostics is a test of object response to the impact of energy causing change of its technical condition [9]. As far as the destruction of the object model is concerned we find that the degree of wear of the machine is proportional to the energy dissipated from it.

scholarly journals Influence of Age on the Technical Wear of Tenement Houses

2020 ◽  
Vol 11 (1) ◽  
pp. 297
Author(s):  
Jarosław Konior ◽  
Marek Sawicki ◽  
Mariusz Szóstak
Keyword(s):  
Residential Buildings ◽  
Residential Building ◽  
Numerical Approach ◽  
Technical Condition ◽  
Visual Methods ◽  
Secondary Importance ◽  
Building Maintenance ◽  
Technical Maintenance ◽  
Traditional Construction ◽  
The Impact

The research presented in the article, which includes methods, models, and conclusions, contains synthetic and analytical model solutions concerning the problems of the technical maintenance and wear of residential buildings with a traditional construction. The cause and effect relationships between the occurrence of damage in the elements of tenement houses (treated as proof of their maintenance conditions), and the size of the technical wear of these elements were determined using a representative and purposefully selected sample of 102 residential buildings erected during the second half of the nineteenth and early twentieth centuries in Wroclaw’s “Downtown” district. Quantitative damage analysis, which was carried out using empirical (visual) methods of assessing the technical condition of a building, indicates the type and size of damage to the building’s elements that are characteristic for the relevant maintenance conditions. Research concerning the cause–effect relationships (“damage–technical wear”) in observed states allows for a numerical approach to the impact of building maintenance conditions on the degree of the technical wear of its components. The maintenance and exploitation conditions determine the degree of the technical wear of the elements of an old residential building. The exploitation condition of these buildings is manifested by damage to elements caused by water and moisture penetration, which is especially important for poorly maintained buildings. The article shows that the age of the elements of an old residential building with a traditional construction is of secondary importance in the process of the intensity of losing its serviceability value. It was calculated that no more than 30% of the damage of building components is explained by the passage of time, and it is therefore not age that determines the course of the technical wear of the elements of the analyzed tenement houses.

The Specific Characteristics of Shock and Blast Impacts on Construction Sites

2021 ◽  
pp. 81-88
Author(s):  
A.A. Komarov ◽  
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Potential Hazard ◽  
Construction Sites ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Plane Crash ◽  
Nuclear Plants ◽  
The Impact

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.

The Influence of Diagnostic Signal Measurement Period on Blades Technical Condition Images Determined from Phase Shift Difference

2013 ◽  
Vol 199 ◽  
pp. 67-72 ◽  
Author(s):  
Rafał Grądzki
Keyword(s):  
Phase Shift ◽  
Damage Detection ◽  
Technical Condition ◽  
New Method ◽  
Diagnostic Model ◽  
Inductive Sensor ◽  
Blade Tip ◽  
Space Range ◽  
Measurement Period

In the article, new method of monitoring of rotor machine blades technical condition is presented. This method is based on diagnostic model φT12T01 [ which uses phase shift difference of signal fragments resulting from blade operation y (t) during blade recession from sensor and during approach of blade tip towards the sensor as well as signal of its environment x (t) described using proper distribution. The assumed diagnostic model also indirectly includes actual blade environment x (t) without necessity of its measurement [3,. Contactless inductive sensor constantly measures the signal of operating blade transition below the sensor. However, several difficulties with determination of last sample of blade receding from the sensor with first sample of blade approaching the sensor exist. Additionally the problem occurs with measurement of space between blades. So far, the case was solved by use 90% of this space range (in order to eliminate the overlapping of adjacent blades signals). Hence the problem of assessment of measurement period breadth on obtained models (images) of blades. The possibility of blade damage detection by analysis of less than 90% signal course was tested.

scholarly journals TECHNICAL CONDITION OF CORRUGATED METAL TRANSPORT STRUCTURES

2021 ◽  
pp. 38-50
Author(s):  
J. J. LUCHKO ◽  
V. V. KOVALCHUK
Keyword(s):  
Bearing Capacity ◽  
Technical Condition ◽  
The Body ◽  
Soil Environment ◽  
Metal Structures ◽  
Advantages And Disadvantages ◽  
Methods Of Calculation ◽  
Analysis And Synthesis ◽  
The Impact ◽  
Corrugated Metal

Purpose. The purpose of the work is to establish the real technical condition of transport structures made of corrugated metal structures on the basis of the analysis of scientific and technical sources.And to analyze the experience of operation of metal corrugated structures in the soil environment and to form and generalize the problems of ensuring the reliability and durability of structures made of metal corrugated structures in the conditions of operation on railways and highways of Ukraine. Methodology. To achieve this goal, a review of scientific and technical sources and regulations of different countries on the technical condition of transport facilities in Ukraine was conducted. In particular, data on the distribution of bridges and pipes made of corrugated metal structures by mode of transport are given. It is shown that the development and implementation of new technologies for the repair of existing defective pipes and small bridges, both on the railways and highways of Ukraine is a very important issue. A thorough analysis of the experience of operation of corrugated metal structures in the soil environment in different countries was conducted. Data on the main inadmissible defects of pipes and the reasons of their development are given. CMS' (corrugated metal structures) corrosion and other defects are given. A number of examples of overpass defects, collapse of bridges and structures with MCS in operation are presented. The qualitative indicators of metal corrugated structures, their advantages and disadvantages are also considered, the problems and the analysis of ensuring the reliability and durability of the structures with CMS in the conditions of operation on the railways and highways of Ukraine are formulated. Findings. An analysis of domestic and foreign scientific and technical sources on the technical condition of transport facilities in Ukraine was conducted. In particular, the experience of operation of corrugated metal structures in different countries of the world is studied and generalized. The analysis and synthesis of problems of ensuring the reliability and durability of buildings with CMS in the conditions of operation on the railways and highways of Ukraine. Originality. As a result of the analysis of the technical condition of transport facilities operated on railways and highways of Ukraine, it was found that about 15 % of transport facilities – small and medium bridges and culverts on Ukrainian railways and about 45 % of transport facilities on Ukrainian roads have unacceptable defects and require immediate repair and replacement. Also, it was established on the basis of research that there are no methods for assessing the load-bearing capacity of transport facilities with CMS in the presence in the body of the embankment of the railway or highway metal corrugated structures with a diameter greater than 6 m. It was determined that standards don't include regulations on design and monitoring of CMS on railway tracks. Practical value. On the basis of these data it was possible to offer directions of theoretical and experimental research and methods of calculation, tests of CMS and diagnostics of a technical condition of transport structures with CMS. In particular, the measurement of the impact of the environment on the bearing capacity of the CMS and the measurement of residual deformations of the corrugated metal pipe on the railway track. Execution of the analysis and synthesis of methods of calculation of transport constructions with CMS will lead to improvement of methods of calculation of CMS.

scholarly journals THE MATHEMATICAL MODELLING METHODS APPLYING TO ESTIMATE THE PIPELINES TECHNICAL STATE AND ENVIRONMENT SITUATION

2019 ◽  
pp. 97-103
Author(s):  
A. P. Oliinyk ◽  
G. V. Grigorchuk ◽  
R. M. Govdyak
Keyword(s):  
Boundary Conditions ◽  
Oil And Gas ◽  
Equation System ◽  
Technical Condition ◽  
Original Method ◽  
Two Dimensional ◽  
Navier Stokes Equation ◽  
Emergency Situations ◽  
Negative Impacts ◽  
The Impact

In the context of providing trouble-free operation of oil and gas pipelines and preventing possible negative impacts on the environment, the issues of constructing an integrated mathematical model for assessing the technical condition of pipelines and the impact of emergency situations on the state of the environment in the course of hydrocarbon leakage are considered. The model of the evaluation of the stress-strain state of the pipeline according to the data on the displacement of surface points for the above ground and underground sections is given by constructing the law of motion of the site by known displacements of a certain set of surface points using assumptions about the type of deformation of the sections and reproduction of the deformations and stresses tensors components   on the basis of different models of deformed solid body. The specified model does not require information on the whole complex of forces and loads acting on the investigated object during operation. The flow model has been refined in a pipeline with a violation of its tightness by recording a special type of boundary conditions for a Navier-Stokes equation system in a two-dimensional formulation and developing an original method for its solution on the basis of the finite difference method. In the article the stability conditions of the proposed numerical schemes on basis of the spectral sign of stability are presented. In order to assess possible negative impacts on the environment, a model of propagation of matter at its leakage from the pipeline was developed by solving two-dimensional diffusion equations taking into account the variables and different types of boundary conditions that take into account the number of sources of pollution and their intensity. The results of computations based on computational algorithms implemented by these models and graphic material illustrating these calculations are presented, peculiarities of distribution of harmful substances in the environment near the pipeline are analyzed. Directions of further researches for successful practical realization of the offered models are established.

scholarly journals Modelling the impact of a new tobacco product: review of Philip Morris International’s Population Health Impact Model as applied to the IQOS heated tobacco product

2018 ◽  
Vol 27 (Suppl 1) ◽  
pp. s82-s86 ◽  
Author(s):  
Wendy B Max ◽  
Hai-Yen Sung ◽  
James Lightwood ◽  
Yingning Wang ◽  
Tingting Yao
Keyword(s):  
Population Health ◽  
New Product ◽  
Health Impact ◽  
Tobacco Product ◽  
Dynamic State ◽  
Model Parameters ◽  
Impact Model ◽  
Tobacco Products ◽  
Philip Morris ◽  
The Impact

ObjectivesWe review the Population Health Impact Model (PHIM) developed by Philip Morris International and used in its application to the US Food and Drug Administration (FDA) to market its heated tobacco product (HTP), IQOS, as a modified-risk tobacco product (MRTP). We assess the model against FDA guidelines for MRTP applications and consider more general criteria for evaluating reduced-risk tobacco products.MethodsIn assessing the PHIM against FDA guidelines, we consider two key components of the model: the assumptions implicit in the model (outcomes included, relative harm of the new product vs cigarettes, tobacco-related diseases considered, whether dual or polyuse of the new product is modelled, and what other tobacco products are included) and data used to estimate and validate model parameters (transition rates between non-smoking, cigarette-only smoking, dual use of cigarettes and MRTP, and MRTP-only use; and starting tobacco use prevalence).ResultsThe PHIM is a dynamic state transition model which models the impact of cigarette and MRTP use on mortality from four tobacco-attributable diseases. The PHIM excludes morbidity, underestimates mortality, excludes tobacco products other than cigarettes, does not include FDA-recommended impacts on non-users and underestimates the impact on other population groups.ConclusionThe PHIM underestimates the health impact of HTP products and cannot be used to justify an MRTP claim. An assessment of the impact of a potential MRTP on population health should include a comprehensive measure of health impacts, consideration of all groups impacted, and documented and justifiable assumptions regarding model parameters.

Monitoring of the technical condition of tracks based on machine learning

2019 ◽  
Vol 234 (7) ◽  
pp. 702-708
Author(s):  
Bartosz Firlik ◽  
Maciej Tabaszewski
Keyword(s):  
Machine Learning ◽  
Threshold Value ◽  
Technical Condition ◽  
Learning System ◽  
Mean Square ◽  
Vibration Acceleration ◽  
Vehicle Velocity ◽  
Track Condition ◽  
The Cost ◽  
The Impact

This paper presents the concept of a simple system for the identification of the technical condition of tracks based on a trained learning system in the form of three independent neural networks. The studies conducted showed that basic measurements based on the root mean square of vibration acceleration allow for monitoring the track condition provided that the rail type has been included in the information system. Also, it is necessary to select data based on the threshold value of the vehicle velocity. In higher velocity ranges (above 40 km/h), it is possible to distinguish technical conditions with a permissible error of 5%. Such selection also enables to ignore the impact of rides through switches and crossings. Technical condition monitoring is also possible at lower ride velocities; however, this comes at the cost of reduced accuracy of the analysis.

scholarly journals Research on Meshing Characteristics of Shearer Walking Wheel Based on Rigid-Flexible Coupling

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Lirong Wan ◽  
Dejian Ma ◽  
Xin Zhang
Keyword(s):  
Load Distribution ◽  
Impact Load ◽  
Dynamic State ◽  
Transition Curve ◽  
Force Model ◽  
State Equations ◽  
Flexible Coupling ◽  
Longitudinal Load ◽  
Meshing Characteristics ◽  
The Impact

Frequent failure of the walking wheel seriously restricts the performance of the whole shearer. To reduce the failure rate and improve the working performance of the walking wheel, the meshing characteristics of the tooth pin are researched. The dynamic state equations of the walking wheel and the contact force model of tooth pin meshing are established. The rigid-flexible coupling simulation model of tooth pin meshing is built. The load distribution characteristics of the walking wheel are analyzed, as well as the effects of impact load amplitude and duration. Results show that the curve of the longitudinal load distribution coefficient (Kβ) of the contact area is W-shaped, with a maximum of 1.325 at the moment of a single tooth contact. The end of the transition curve is the most serious position of the longitudinal load imbalance at the tooth root. In addition, on the impact moment, Kβ tends to decrease and maximum stress obviously increases with the increase in impact load under 40%; the material at the contact position will fail under an extra 39% instantaneous impact load. Furthermore, with the impact load of 30%, the influence of load impact duration under 0.5 s on the meshing characteristics of the walking wheel is relatively faint. The results provide some guidance for the design optimization of the walking wheel and provide a reference for improving the reliability of the shearer.

Analysis of Stresses Induced by Dynamic Load Head-Disk Contacts

1999 ◽  
Vol 122 (1) ◽  
pp. 233-237 ◽  
Author(s):  
Ta-Chang Fu ◽  
David B. Bogy
Keyword(s):  
Dynamic Load ◽  
Maximum Stress ◽  
Radius Of Curvature ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Impact Stress ◽  
Dual Channel ◽  
Average Maximum ◽  
The Impact ◽  
Maximum Contact

The dynamic load head-disk contact induced impact stress was studied. A dual channel LDV was used to measure the head-disk relative motion during impact, and an analytical model incorporating the Hertz theory of impact was developed to quantitatively estimate the impact induced contact force and stress based on the LDV-measured results. 70 percent sliders were used in order to compare the results with our previous study. From the estimated maximum contact stresses and the results of our previous study, it was found that when the average maximum stress was 511 MPa, the head-disk interface did not show any damage after 100,000 cycles of repeated head-disk impacts. When the average maximum stress was 880 MPa, however, 100,000 repeated head-disk impacts caused significant wear of the disk’s overcoat even though a single impact did not cause any observable damage. From the analysis it can be seen that a lower head-disk impact velocity and/or a larger radius of curvature at the contacting corner of the slider result in a smaller head-disk impact stress on the disk. Based on the analyses, we estimated the radius of curvature needed for a 50 percent (Nano) slider and a 30 percent (Pico) slider to have at least 100,000 cycles of dynamic load head-disk interface durability. Such radius of curvature can be realized, for example, by edge-blending the sliders. [S0742-4787(00)02901-5]

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