SU1651145A1 - Device for static testing mechanical strength of structures - Google Patents

Abstract

The invention relates to testing equipment, in particular to devices for static strength testing of full-scale structures. The purpose of the invention is to improve the accuracy by measuring the voltages immediately after the decay of transients. Each of the loading channels of the structural elements 8 contains the exciter 1 with the executive body 2, the amplifier-conversion unit (B) 6. associated with the body 2, the comparison circuit 5, the output of which is connected to B 6, the setting unit 3 and the sensor (D) 4 forces connected to the inputs of the circuit 5. All channels are connected to the D 7 voltage associated with the structural elements 8. measuring system 9 associated with D 4,7, software B 10 whose outputs are connected with the setting device 3, B 11 emergency protection, the outputs of which are connected to the outputs of circuits 5 and D 4, and the outputs - from the bodies 2, and the analyzer 12 signals D voltage and misalignment in the loading channels, the outputs of which are connected with the command inputs of the system 9 and B 10, 11 Shows an embodiment of the analyzer 12, based on the development of commands to register readings D 4 and 7 and the transition to the next reference point of loading after the coincidence of three consecutive measurements from D 4,7 and schemes 5. At the command B 10, converted by setting devices 3, B 6 and by the executive bodies 2, exciters 1 load the structural elements 8 After completion of the transition the running processes in the design 8 and the loading system, the analyzer 12 issues a command to the system 9 to register stresses and forces and B 10 to go to the next reference point of loading 1 Cp. f-ly, 2 ill. (L S o SL

Description

The invention relates to testing equipment, in particular to devices for static strength testing of full-scale structures.

The purpose of the invention is to improve the accuracy by measuring the voltages immediately after the decay of transients.

Figure 1 shows a block diagram of a device for static testing of structures for strength; FIG. 2 is a block diagram of a voltage sensor signal analyzer; FIG.

elements of the tested design and mismatch in the loading channels.

The device contains loading channels of the test structure with closed control loops, each of which includes an energizer 1 (for example, a power hydraulic cylinder); Executive body 2 (for example, an electro-hydraulic converter); 3 force adjuster, 4 force sensor (for example, strain gauge). control loop feedback: signal comparison circuit 5

N ate

the sensor 4 and the setpoint 3 of the efforts, the output of which (the error signal) is proportional to the deviation of the actual load value from the set one; an amplifier and converter unit 6, which forms a control signal from the error signal (for example, by a proportional-integral-differential law), directed to the input of the actuator 2 (the signal comparison circuit 5 and the amplifier and converter unit b are load regulator). In addition, the device contains common for all loading channels voltage sensors 7 in the elements of the test structure 8 (for example, strain gages). the number of which, in general, does not depend on the number of loading channels; measuring system 9, to the input of which voltage sensors 7 and forces 4 are connected; a software unit 10 controlling the operation of the drivers of the 3 loading channel forces; block 11 emergency protection; analyzer 12 of sensor signals of voltage 7 and mismatch in the loading channels to determine the end of the transient processes in the test structure 8 and the loading system, the inputs associated with the outputs of the voltage sensors 7 and comparison circuits 5, and the outputs with command inputs of the software unit 10, the measuring system 9 and the emergency protection unit 11 (in general, not all 7 voltage sensors can be connected to the analyzer, but only some of them that allow you to control transient conditions with the necessary reliability processes in the test structure) .i

The analyzer 12 with voltage sensors 7, comparison circuits 5 and measuring system 9 forms a closed loop controlling the process of determining the static strength characteristics of the test structure 8 (control system with track control).

As program block 10, a multi-circuit time relay or computer is used. At the same time, along with the control function of the setting devices for 3 efforts, the computer can participate in the solution of other problems associated with the removal, processing, recording and storage of data for the strength static characteristics.

As the measuring system 9 can serve various multichannel two-coordinate recorders, information-measuring systems, etc.

The readings of sensors 4 and 7 can be stored in the computer memory and according to the data obtained as a result of their processing in a computer (in the case of

for example, static processing of data obtained by repeated passing of reference points), the static characteristic is built in the plotter under

computer control, displayed on an alphanumeric display, alphanumeric printing device, etc.

The emergency protection unit 11 is constructed according to standard schemes. In block 11, not only the output of the analyzer 12 is connected, but also other elements (in particular, force sensors 4 and comparison circuits 5 and sensors of damage to the test structure, etc.) that are not shown on the circuit, monitoring as

5 health and normal functioning of the elements of the test apparatus, as well as the condition of the structure under test. FIG. 2 is a block diagram of one embodiment of the analyzer.

0 12, generating a command to register the readings of sensors 4 and 7 and the transition to the next reference point after the coincidence of three consecutive measurements for each of the monitored voltages in

5 of this reference point, produced with a set periodicity at a sufficiently accurate coincidence of the actual loads t: given values in all load channels (i.e., at sufficiently small results of loading in the load channels). The choice of the number of measurements equal to three is due to the fact that this is the minimum number at which the influence of random errors (emissions) during measurements can be avoided. The measuring and logic system of the analyzer 12 with such a number of measurements is relatively simple.

The analyzer 12 is made with a digital circuit for comparing the indications of sequential measurements and includes a generator 13 of a continuous sequence of pulses (a clock generator) determining the frequency of the measurements made (polling rate); block 14, the control of the error signals of each of the loading channels of the tested structure, containing null indicators 15 error signals in channels with the generators of 16 level signals (for example, a logical unit) corresponding to the operation of null indicators 15. and the coincidence circuit 17 null indicator triggering 15; similar blocks 18 control signals

5 sensors 7 voltages, each of which contains registers 19-21. into which digital codes of voltage values, obtained in analog-to-digital converter (ADC) 22 sensors 7 as a result of successive

measurements with sequential rewriting of codes from one register to another according to the commands of the generator 13; calculators 23-25 differences of codes of each of the pairs of registers 19-21; null indicators 26 connected to the output of each of the solvers 23-25; drivers 27 of logic level signals corresponding to triggering null indicators 26; circuit 28 coincidence of the operation of null indicators 26; a coincidence circuit 29, at the output of which, when the 17 control circuits 17, 28 are triggered, signals appear to open the information from the sensors 4, 7 to the measurement inputs of the system 9 and record readings at this reference point and to act on the command the entrance of the program block 10, which provides the transition to the next reference point, with a delay sufficient to complete the registration process of the readings; pulse counter 30 from the moment of receiving the command to go to the reference point to the moment of completion of measurements at this reference point, acting on the emergency protection block 11 via the overflow signal bus when the transient damping duration in the test structure 8 and the loading system increase, indicating its malfunction (bus Reset counter 30 is connected to the output of the coincidence circuit 29).

Fundamentally, it is possible to do without the 17, 28 coincidence circuits in the analyzer, if the drivers 16 and 27 are connected directly to the 29 coincidence circuit made with the corresponding number of inputs.

The analyzer 12 can be performed not only with a digital read comparison circuit, but also with an analog one.

The device works as follows.

The process of determining the static strength characteristics consists in sequential measurement of the loads excited in all channels during the transition from one reference point to another with recording the readings of sensors 4 and 7 at the moments of decay of transients in the test structure 8 itself and in the system of its loading.

Before the device starts working, the program for changing the load in each of the loading channels as a function of time is entered into the program block 10. The program determines the rate of change of loads during the transition from one reference point to another, the values of loads in the reference points, the number of reference points in the working range of load changes, the number of load range passes with statistical processing of measurement results, etc. The duration of exposure at the reference points is determined by during the removal of the characteristics of the duration of transient processes in the structure under test and the loading system (the command to terminate the exposure for each reference point comes from izatora 12).

0When the device is turned on by drivers

3 forces under the action of the program block 10 are given tasks for the loading channels, which begin to load the tested structure 8 with forces corresponding to the first reference point. At the same time, the analyzer 12 starts to reboot. When the reference point is reached, the signals of the setters of the 3 efforts are fixed (frozen). At each clock

0 pulse generator 13 in the register 19 for each of the blocks 18 of the control signals of the sensor 7 voltage is entered the code of the new indication, and the previous reading from the register 19 is written to register 20, and

5 from register 20 to register 21. At the rate set by the hererate 13, the contents of registers 19-21 are read to computers 23-25 and the readings are compared. At the same time in

In block 14, the mismatch is controlled in all loading channels. When coinciding with the accuracy specified by the setting of the null indicators 26, the last three readings recorded in registers 19-20 for

5 of each of the blocks 18 controlling the signals of the sensors 7 and the coincidence of the set and actual values of the loads in the loading channels with the accuracy specified by the setting of the null indicators 15, the signals from the outputs

0 drivers 27,16 are passed to coincidence circuits 28, 17, which then work and provide the operation of the general coincidence circuit 29, issuing commands to enable the recording of the readings of sensors 5 and 7 by measuring system 9 and reset the counter 30. With time delay, sufficient to complete the registration process, a command is also issued to the software block 10 to move to the next reference point. The load on the tested structure 8 is changed again until the value corresponding to the new rep dawn point, etc. The process continues until

5 data will not be received at all fixed points.

If the transient process at one of the track points is delayed due to faults in the loading channels, damage to the test structure 8, etc.

This leads to overflow of counter 30 and the inclusion of block 11, signaling disturbances in the normal course of measurements and stopping (by acting on the executive bodies 2) the testing process (or initiating other anti-emergency operations).

Thus, the invention makes it possible to increase the accuracy of measuring stresses in the elements of the tested structure in the process of removing its strength characteristic while minimizing the time spent on measurements; expand the functionality of the device by ensuring control of the state of the tested structure not only by the parameters of strength static characteristics, but also by the duration of transients in the tested structure and in the loading system; to increase the degree of automation of the measurement process due to the automatic installation of the minimum required step length at the reference point, at which measurements are carried out after the transients in the structure under test and the loading system are attenuated.

Claims (2)

Claim 1. A device for static structural testing of strength, containing several loading channels, each of which includes an exciter with an actuator, an amplifier-converter unit associated with the executive organ, a comparison circuit, the output of which is connected to an amplifier and preobazing unit, for a sensor and a force sensor connected to the inputs of the comparison circuit, and also voltage sensors common for all load channels, designed to be placed on console elements the measuring system associated with the voltage and force sensors, the program block whose outputs are connected to the force adjusters, and the emergency protection block whose inputs are connected to the outputs of the comparison circuits and the force sensors, and . that, in order to increase accuracy by measuring voltages directly after transient decay, it is equipped with a signal analyzer, the inputs of which are connected to voltage sensors and outputs of comparison circuits, and the outputs are connected to command inputs of the measuring system, software unit and alarm unit protection. 2. Device pop. 1, characterized in that the signal analyzer is made in the form of a generator and pulse counter associated with an emergency protection unit, a unit for controlling the error signal for each loading channel, including null indicators associated with the circuits comparisons, and matching schemes of null-indicator triggers. voltage sensor control blocks, each of which contains registers related to the generator and voltage sensors according to the number of compared sensor readings, calculators of codes difference of each of the register pairs, additional null indicators connected to the output of each of the computational difference and the coincidence circuit of these null-indicators, and the general coincidence circuit, the inputs of which are connected to the coincidence circuits of all the control units, and the outputs - to the bus of the pulse counter and command inputs of the measuring system emy and packagers. Oto From 7