SU937998A1 - Device for measuring structure elastic deformation - Google Patents

Description

one

The invention relates to a measurement technique, namely strain gauge strain gauges, and can be used in studies of strain fields on elastic elements of pressure sensors or parts and structural elements.

A device for measuring elastic deformations of structures is known, which contains a set of strain gauges, Q deformations and a multi-channel recorder connected to them based on an electronic computer l.

However, this device requires a large number of sensors and measurement channels and does not provide for high measurement accuracy, since the strain sensors are placed at different points in the field and their signals depend randomly on the installation site on the part. 20

The closest to the invention in technical essence and the achieved effect is a device for measuring elastic deformations of a structure.

containing a set of strain gauge strain sensors, grouped in groups of several sensors with different measurement bases, established symmetrically with respect to the common point of the center of symmetry, and a multichannel recorder t2l connected to the sensors.

However, this device also requires a large number of measurement channels, including sensors, communication lines and recorder channels, and its accuracy is limited due to the impossibility of placing groups of sensors at close distances from each other, which is necessary for detecting the fine structure of the deformation field.

The purpose of the invention is to improve the accuracy and reduce the number of measurement channels.

Claims (2)

The goal is achieved by the fact that in a device for measuring elastic deformations of a structure, containing a set of strain gauge strain gauges and a multi-channel recorder connected to them, the sensors are made with a variable length sensitivity, varying accordingly for each sensor according to its basic function assigned for spatial description nor the field of elastic deformations. FIG. 1 shows the block diagram of the device; in fig. 2 illustrates the implementation of sensors with variable sensitivity in functions of the Fourier trigonometric series 5 in FIG. 3 - the same, according to Walsh-Hadamard function; in fig. 4 is the same according to the Walsh function; Fig 5 is the same in terms of the Haar functions; in fig. b - the same, according to Legendre functions of the first kind; in fig. 7 the same, according to the impulse weighting functions of the filters of low spatial HbDC frequencies; in fig. 8 - by impulse weighting functions of spatial frequency bandpass filters; in fig. 9 By impulse weighting functions of low spatial frequency filters in multi-channel version. The device contains a set of strain gauges 1, placed on the structure by 2 groups of several parallel sensors with the corresponding required basic functions, the values of the local sensitivity UQ, and, Uj. . . .and, and according to for the non-elastic element X, achieved, for example, by profiling the width or thickness of the strain gauges, link 3 and multi-channel 1st recorder 4. The device works as follows. When local deformation occurs in the places where strain gauges 1 are installed on structure 2, the signal from each sensor is like the sum of the signals of elementary low-base strain gauges added with different weights. The output signal from each sensor is, therefore, a value that directly characterizes the coefficients of the terms in the used field decomposition into basis functions. Signals from sensors 1 are recorded via line 3 of the multichannel registrator 4 connection. Choosing a Defined system of basic functions suitable for describing the original function of the elastic deformation field profile of the structure, in each case with 1р / ;; eats vgs both the type of the initial function and assigned task. Thus, for example, for smooth periodic functions (measurement of the deformation field profile of a twisted elastic element), the same accuracy can be achieved with a smaller number of Fourier trigonometric series than with decomposition in the Walsh series and, conversely, for a stepped field profile characteristic For example, for a shifted elastic element of a stepped shape, it is advisable to use the Walsh-Hadamard functions. The choice of the optimal system of functions allows reducing the number of sensor elements and, consequently, simplifying the device. On the other hand, the solution of many problems of logical information processing, where, as a rule, a limited number of deterministic classes of input signals is assumed, is greatly simplified when using a harmonic or other complete standard basis for the description of the signal, emphasizing the informative features of the signal. In particular, when measuring the profile of the deformation floor of an elastic element, the choice of the optimal basis makes it possible to group the class attributes of the measured magnitudes and simplify the measurements. The most important criterion determining the perspectivity of the device is the large value of the threshold sensitivity. Thus, the application of the proposed device allows to increase the accuracy of measurements and to perform spatial filtering of the deformation field profile of the elastic element directly by the sensor with a simplified structural implementation. An apparatus for measuring elastic deformations of a structure, comprising a set of strain gauge strain sensors and a multi-channel recorder connected to them, characterized in that, in order to increase accuracy and reduce the number of measurement channels, the sensors are made with a variable sensitivity that varies accordingly for each sensor. . according to its basic function, intended for the spatial description of the elastic strain field. Sources of information taken into account in the examination 1.Patent of Germany No. 15737OOO, cl. Q O1 B 7/18, 1966. 2. The patent of France No. 2422931, cl. G 01 B 7/18, 1979 (prototype). Fut.3 FIG. . FIG 5 (BUT X FIG. 7 Phie.in I B v A / -V / v A, x.- CheHGHH in. Gh / VSUAR / XA - / Fig.d