SU977993A1 - Device for measuring machine building structure fatigue durability - Google Patents

Description

A deformation detector into an electrical signal, an amplifier, an RMS measurement unit and a first nonlinear conversion unit, a reference signal source, a recorder and a nonlinear conversion unit, is equipped with a control unit, first and second frequency dividers, first and second pulse counters, and a zero body. whose input is connected to the output of the amplifier, and the output through the first frequency divider and pulse counter to the input of the control unit, the second nonlinear conversion unit is made in the form of the first impedance matrix, the input of which is connected to the output of the first non-linear conversion unit, and the operational amplifier, the output of which is connected to the recorder, and the second impedance matrix, connected to the output and input of the operational amplifier, and the control inputs of the impedance matrices are connected to the outputs pulse counters of the same name, reference signal source through the second frequency divider and pulse counter to the control unit, the outputs of which are connected to the control m inputs of frequency dividers and recorder.

° The drawing shows the block diagram of the proposed device with

The device contains serially connected converter 1 deformation into an electrical signal, amplifier 2, unit 3 measuring the rms value, first block k of nonlinear conversion, second block 5 of nonlinear conversion, filled in the form of the first impedance matrix 6 connected to the input of the operational amplifier 7 and the second matrix 8 of the resistances connected to the input and output of the operational amplifier 7 connected to the recorder 9. To determine the number of zero crossings of the output from the transducer output The body 1 serves as a circuit including a null-body 10 connected in series, the input of which is connected to the amplifier 2, and the first frequency divider 11 and the pulse counter 12, the outputs of which are connected to the control unit 13 and the control input of the first resistance matrix 6. For the formation of a signal proportional to the current time, serve as a series connected source -; IIIk 1 of the reference signal (executed,; h; - .. example, in the form of a Uv-gv-erator, to the time) and the second divider 15 -c

and a pulse counter 16, the output of which is connected to the inputs BTopoi-i ms 8 of the resistances and the control unit 13; the outputs of which are prepared. The controllers are equipped to the control inputs of the p-zgis oa | opa 9 and frequency dividers 11 and 15

The device works as follows.

The input of the amplifier 2 from the trans: / invoker 1 receives electrical JSC-i-i

a signal corresponding to the dynamic stresses acting on the structure under test. The signal from the output of the amplifier 2 is fed through the unit of measurement of the rms value to the input of the first block 4 of the nonlinear transformation, at the output of which a signal is generated, proportional YY

national S, where S is the root-mean-square value of stresses, n is an indicator of the degree of endurance curve “

The signal from the output of the block is fed to the input of the second block 5 of the nonlinear conversion, which includes an operational amplifier 7, the transmission coefficient of which is determined by the ratio of the conductivities of the first and second 8 impedance matrices. Signal

Claims (2)

from the output of amplifier 2 is also fed to the input of the null organ 10, at the output of which pulses are formed when the signal passes through zero. Pulses through the first frequency divider 11 are fed to the input of the first pulse counter 12, in which the number of zero crossings is counted. The binary code from the output of counter 12 goes to the control input of the first matrix, 6 and establishes its conductivity proportional to the number of zero crossings of the signal, The conductivity of the second matrix 8 is set proportional to the measurement time by the code from the output of the second pulse counter 16, to the input of which pulses are output from the output of the second frequency divider 15. The input of the divider 15 pulses come from the output of the Source 1 of the reference signal. Thus, the transmission coefficient of the operational amplifier 7 is set proportional to the Moft ratio, where gp is the number of zeros of a process of the same character during time t. The dividers 11 and 15 frequencies are used to match the effective process frequencies and the measurement time with the counter size 12 and 16. The division ratio factors are Lees 11 and 15 are carried out by control block 13, from which output to the corresponding multiplier, equal to the ratio of the division factors of dividers 11 and 15, goes to registrator 9. Counter overflow signals Blocks 12 and 16 are fed to the input of control unit 13, while the output of control unit 13 is fed to the control inputs of dividers 11 and 15 of the lock signal, which prevents the passage of pulses to the inputs of counters 12 and 16 " the value of durability, determined from the relation where T is the measured durability, is the proportionality coefficient. The invention improves the accuracy of determining the fatigue life of structures, reducing the instrumental error of the device. Claims An apparatus for measuring the fatigue life of a machine-building structure, comprising a series-connected strain-to-electrical converter, an amplifier, an RMS measurement unit and a first non-linear conversion unit. the reference signal source, the recorder and the second nonlinear conversion unit, characterized by the tag, which, in order to improve the measurement accuracy, is equipped with a control unit, first and second frequency dividers, first and second, pulse counters and null organ, whose input is connected to the output of the amplifier and the output through the first frequency divider and pulse counter to the input of the control unit, the second nonlinear conversion unit is made in the form of serially connected first resistance matrix, the output of which is connected to the output ervogo nonlinear conversion unit, and an operational amplifier whose output is connected to the recorder, as well as secondary. a matrix of resistances connected to the output and input of the operational amplifier, the control inputs of the resistance matrices connected to the outputs of the same pulse counters, the source of the disputed signals connected via the second frequency divider and the pulse counter to the control unit whose outputs are connected to the control inputs of the frequency divider and the registrar. Sources of information taken into account in examination 1 of the USSR Author's Certificate tf, class, 01 N 3/06, 1977. 2. USSR author's certificate N, Clo G 01 N 3/06, 1978. (pototip).