scholarly journals ОПТИМІЗАЦІЯ ВИМІРЮВАЛЬНИХ ЗАСОБІВ НАПРУЖЕНО-ДЕФОРМОВАНОГО СТАНУ ЗА ДОПОМОГОЮ ТЕНЗОДАТЧИКІВ

2019 ◽  
pp. 50-56
Author(s):  
Людмила Володимирівна Кузьмич ◽  
Дмитро Петрович Орнатський ◽  
Володимир Павлович Квасніков
Keyword(s):  
Strain Gauge ◽  
Strain State ◽  
Approximation Error ◽  
Strain Gauges ◽  
Mean Square ◽  
Stress Strain ◽  
Stress Strain State ◽  
Destabilizing Factors ◽  
Mechanical Factors ◽  
The Mean

In the article, the principles of construction, design and mathematical modeling of deformation and stresses of complex technical constructions are developed with the help of strain gauges and strain gauges taking into account destabilizing factors, which allows to significantly reduce the level of errors in relation to existing measurement methods and known analogs.The method of digital compensation provides a more significant reduction in the errors of measuring transducers compared with the method of analog compensation. Features and technical indicators of this method are considered on an example of measuring pressure transducer with foil strain gauges.This method is universal, allows us to adjust not only the errors of the measurement channel nonlinearity and additional errors but also the errors associated with the effect of interferences of the general type due to ground resistance, which induces the connection between the measuring channels of the main and destabilizing factor.The disadvantages of this method include a significant amount of computations, which sharply increases with increasing order of approximating polynomials.The purpose is to develop a method and means of measuring stress-strain state using strain gauge, free from the above - mentioned shortcomings.The main destabilizing factors that limit the measurement accuracy using strain gauge are:- random processes (noises, obstacles, etc.);- changes in parameters of measuring transducers due to aging and physical degradation;- effects of external climatic and mechanical factors (temperature, humidity, etc.).The influence of the main destabilizing factors limiting the accuracy of the measurement of the stress-strain state of complex technical constructions with the help of strain gauges was analyzed, among which the influences of external climatic and mechanical factors are one of the most important ones. Regarding the systematic components, the most important in statistical measurements are the errors of nonlinearity and the temperature component of the error.For the study, two main alloys were taken, which today has the widest use as a material for strain gauges - it is constantan and karma. For these materials, the influence of the range of temperature changes, the spread of the values of temperature error on the mean-square value of the error of approximation by power polynomials was investigated.Using the NUMERY package, the dependence of the approximation error on the order of the approximating polyphony was determined. It is established that the mean square error value in the wide temperature range for both constantan and karma has a weak correlation with the order of a polynomial.

scholarly journals Comparison analysis of using micrometers and strain gauges for measuring deformations and loads in the method of monitoring the stress-strain state

2021 ◽  
Vol 18 (3) ◽  
pp. 71-75
Author(s):  
M. O. Lobovskiy ◽  
◽  
A. L. Tukkiya ◽  
P. A. Pyatkin ◽  
◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Strain Gauge ◽  
Laboratory Tests ◽  
Strain State ◽  
Field Tests ◽  
Strain Gauges ◽  
Construction Site ◽  
Comparison Analysis ◽  
Stress Strain ◽  
Stress Strain State

The micrometer method for measuring deformations and loads in bar elements has proved to be effective not only in laboratory tests, but also in field tests on a real construction site. Having carried out a comparative analysis of the method proposed by the authors for monitoring the stress-strain state (SSS) with the strain gauge method which is widely used at present, the authors have proved that the method for measuring deformations and loads using a micrometer is not inferior in accuracy to the strain gauge method, although it is much cheaper.

scholarly journals Synthesis of Measurement Method of Stressed — Deformed Condition of Complex Structures

2019 ◽  
pp. 12-18
Author(s):  
L. Kuzmych
Keyword(s):  
Strain State ◽  
Theoretical Calculations ◽  
Measuring System ◽  
Strain Gauges ◽  
Complex Structures ◽  
Stress Strain ◽  
Stress Strain State ◽  
Destabilizing Factors ◽  
Remote Measurements ◽  
Time Changes

Nowadays the most common instruments of measuring the stress-strain state of complex structures are strain gauges. As a rule, strain gages are connected to the measuring system according to the bridge scheme, it provides elimination of systematic errors of measurement and compensation of temperature deformations. The principles of constructing, designing and mathematical modeling of deformation and stresses of complex technical constructions with the help of strain gauges taking into account destabilizing factors are developed, which allows to significantly reduce the level of errors in relation to existing methods of measurement and known analogues. The analysis of the main destabilizing factors that limit the accuracy of measurement using strain gauge is carried out, are (Fig. 1—4): the random processes (noises, obstacles, etc.); the time changes of parameters of measuring transducers due to aging and physical degradation; the influence of external climatic and mechanical factors (temperature, humidity, etc.). The temperature error values are set for the most common alloys used for the manufacture of strain gauges, namely: constantan and karma. This work is aimed at finding ways to improve the accuracy of remote measurements and impedance of measuring devices of the stress — strain state, in particular strain gauges and strain gauges, by introducing improved theoretical calculations taking into account destabilizing factors, which makes it possible to reduce the level of errors with respect to known analogs in dozens of times.

scholarly journals Измерение напряженно-деформированного состояния деталей АГТД методом тензометрии

2021 ◽  
pp. 44-51
Author(s):  
Сергей Сергеевич Крыгин ◽  
Юрий Иванович Торба
Keyword(s):  
Strain Gauge ◽  
Electromagnetic Interference ◽  
Strain State ◽  
Total Error ◽  
Current Collector ◽  
Measuring Channel ◽  
Recording Equipment ◽  
Stress Strain ◽  
Advantages And Disadvantages ◽  
Stress Strain State

The subject of study in the article is various methods of measuring the stress-strain state of AGTE parts by the tensometry method. Differences were revealed when measuring the stress-strain state of rotor and stator parts, in different frequency ranges (study of static, static-dynamic and dynamic deformations). Methods for compensating or reducing the influence of external factors on the measurement results, such as temperature changes and electromagnetic interference, are indicated. The aim is to develop recommendations for research of AGTE parts in a test bench in a gradient of varying temperatures and in a complex electromagnetic environment of the engine. A review of the sources of inaccuracies, errors and interference arising during preparation for testing and directly during the measurement of the SDS of AGTE parts is performed. The effects of wiring, cabling, grounding and shielding can not only increase the level of errors, but can also negate the advantages of an expensive and extremely reliable electronic part of the system. The advantages and disadvantages of the most common schemes for connecting strain gages, as well as their areas of application are presented. Possible ways to compensate for imaginary deformations at temperatures outside the range of thermal compensation of primary converters. A list of common strain gauge systems with their advantages and disadvantages is given for each type of parts and frequency ranges of measurements. When strain measurement rotary parts to output the signal from the strain gauge to recording equipment used various current collector. The possibility of using wireless interfaces for communication between the primary converter and the recording equipment is also indicated. The described methods are: ways to compensate for imaginary deformations caused by changes in the temperature of the investigated part and connecting wires. Elimination or minimization of electromagnetic interference on the measuring channel. An estimate is given of the total error in measuring the deformation for a particular object under study for the final loading cycle, the specificity of the bench strain gauge path, the errors of the current collector in bench conditions, and others in the process of static strain gauging.

Investigation of the stress-strain state of lock gates on a strain-gauge model

1988 ◽  
Vol 22 (2) ◽  
pp. 109-113
Author(s):  
V. S. Gavrish ◽  
V. F. Prostak ◽  
V. N. Khimin
Keyword(s):  
Strain Gauge ◽  
Strain State ◽  
Gauge Model ◽  
Stress Strain ◽  
Stress Strain State

КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ ХВОСТО-ВИХ БАЛОК СІТЧАСТОГО ТИПУ З ПОЛІМЕРНИХ КОМПО-ЗИЦІЙНИХ МАТЕРІАЛІВ ВЕРТОЛЬОТІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ

2020 ◽  
pp. 15-30
Author(s):  
А. Г. Гребеников ◽  
И. В. Малков ◽  
В. А. Урбанович ◽  
Н. И. Москаленко ◽  
Д. С. Колодийчик
Keyword(s):  
Finite Element ◽  
Strain State ◽  
Layer Structure ◽  
Metal Structure ◽  
Element Model ◽  
Stress Strain ◽  
Element Analysis ◽  
Mesh Structure ◽  
Stress Strain State ◽  
Mesh Structures

The analysis of the design and technological features of the tail boom (ТB) of a helicopter made of polymer composite materials (PCM) is carried out.Three structural and technological concepts are distinguished - semi-monocoque (reinforced metal structure), monocoque (three-layer structure) and mesh-type structure. The high weight and economic efficiency of mesh structures is shown, which allows them to be used in aerospace engineering. The physicomechanical characteristics of the network structures are estimated and their uniqueness is shown. The use of mesh structures can reduce the weight of the product by a factor of two or more.The stress-strain state (SSS) of the proposed tail boom design is determined. The analysis of methods for calculating the characteristics of the total SSS of conical mesh shells is carried out. The design of the tail boom is presented, the design diagram of the tail boom of the transport category rotorcraft is developed. A finite element model was created using the Siemens NX 7.5 system. The calculation of the stress-strain state (SSS) of the HC of the helicopter was carried out on the basis of the developed structural scheme using the Advanced Simulation module of the Siemens NX 7.5 system. The main zones of probable fatigue failure of tail booms are determined. Finite Element Analysis (FEA) provides a theoretical basis for design decisions.Shown is the effect of the type of technological process selected for the production of the tail boom on the strength of the HB structure. The stability of the characteristics of the PCM tail boom largely depends on the extent to which its design is suitable for the use of mechanized and automated production processes.A method for the manufacture of a helicopter tail boom from PCM by the automated winding method is proposed. A variant of computer modeling of the tail boom of a mesh structure made of PCM is shown.The automated winding technology can be recommended for implementation in the design of the composite tail boom of the Mi-2 and Mi-8 helicopters.

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