SU382964A1 - DEVICE FOR DETERMINATION OF DYNAMIC MODULE OF FIBER AND FILM SHIFT - Google Patents

Description

one

The invention relates to the study of the physico-mechanical properties of fibers and filaments.

The PT device is known for determining the dynamic shear modulus of fibers and radiation, including a generator of probing pulses, an emitter and sensor of ultrasonic torsional vibrations, directional guides, a broadband amplifier, a pulse former, a trigger and a measuring block with a digital or analog output.

However, the known device does not allow measurements of the dynamic shear modulus of anisotroic fibers and filaments.

This is due to the fact that when a transverse (torsional) wave is excited in an anisotropic body, myogomodal elastic oscillations occur, containing both torsional, longitudinal and flexural modes propagating with different group velocities. The existing sensors of torsional collisions are largely sensitive to longitudinal and bending vibrations; therefore, their output voltage, besides the signal of the torsional mode, contains signals of the longitudinal and bending modes superimposed on it.

This leads to the fact that the accuracy of measurements of the velocity of propagation of torsional oscillations by a known device is underestimated and cannot be reliably determined when studying anisotropic fibers and filaments,

since the signals of the longitudinal and torsional modes have similar amplitudes.

The purpose of the invention is to provide an opportunity to study anisotropic fibers and yarns with increased accuracy.

This is achieved by the fact that the proposed device is equipped with a longitudinal vibration sensor, a signal correction unit and a summing unit. The output of the longitudinal vibration sensor is connected to the input of the correction unit, and the output of the correction unit and the output of the torsional vibration sensor are connected to the inputs of the summing unit.

The drawing shows the block diagram of the proposed ycTpoiiCTBa.

The device consists of a generator / probe pulses, radiator 2 high-frequency torsional vibrations, sensor 5 ultrasonic Torsional vibrations, sensor 4 longitudinal vibrations, block 5 of the correction signal of the sensor longitudinal vibrations, summing unit 6, amplifier 7, unit forming the pulses S. trigger 9, from. measuring system st 5a 10, thread guides // n 2.

The device works as follows. From the generator / probe pulses, short electrical impulses of a fixed frequency are transmitted to the emitter, excited in the test image3

CE / J is an elastic torsional pulse of damped harmonic oscillations of an ultrasonic frequency corresponding to its own frequency of the radiator.

At the same time, a delayed pulse is applied from the generator to the input of trigger 9, which changes its initial state. The elastic wave, pro- duced by the scanned pattern, is simultaneously received by sensors 3 and 4 of torsional and longitudinal vibrations. The signal from the sensor of longitudinal oscillations is fed to the input of the corrective unit 5, which is indicative of AMPLT-phase correction by the sigual of the Irodol mode of the torsional vibration sensor. A correspondingly formed from block 5 is simultaneously supplied with a multimode. Signal of torsional vibration sensor 3 to the input of summing unit 6, in which the longitudinal mode signal of the torsional vibration sensor is mutually compensated with a lateral vibration signal of the longitudinal vibration sensor.

The torsional vibration sensor signal selected in this way, corresponding to the torsional mode of the ultrasonic elastic PMD, is fed to the input of the amplifier 7, and then to the shaping unit 6, where it is converted into a standard pulse with an edge

With a red front, overturning trigger U 1 initial positel1 e.

The signal from the trigger is applied to and to: 5meter1 / O device, which does not convert; The trigger pulse duration is equal to the passage time of an elastic round switch in a test image, into a digital or aiial output signal corresponding to the propagation time of a torsional wave or its velocity.

Subject invention

An apparatus for determining the dynamic shear modulus of fibers and filaments contained

probe pulse generator, ultrasonic torsional oscillation emitter and sensor, thread guides, amplifier, Impulse former, trigger, measuring unit, characterized in that, in order to enable anisotropic fibers and utensils to be studied with increased accuracy, it is equipped with a sensor and natural vibrations, correction unit and total block; the output of the longitudinal vibration sensor is connected to the input of the correction unit, and the output of the correction unit and the output of the torsional vibration sensor are connected to the inputs of the summation unit.