RU2366922C1 - Machine for explosion test of soil samples - Google Patents

Abstract

FIELD: physics, tests.

SUBSTANCE: invention is related to testing equipment. Machine comprises loading device with movable and fixed grips of tested sample, electric detector connected to movable grip and loading drive. Electric detector is arranged as inductive, is electrically connected to electronic unit introduced in machine and intended for generation and measurement of sample rupture force, which is in its turn connected to loading drive, which creates linear-growing force of loading prior to the moment of sample rupture.

EFFECT: improved accuracy and provision of possibility to use suggested machine for detection of rupture force in low-strength materials.

2 cl, 3 dwg

Description

The invention relates to testing equipment, and in particular to machines for tensile testing of materials of low strength, mainly soil samples.

To assess the mechanical properties of materials of low strength, it is necessary to accurately measure the value of the force applied to the sample and clearly record the moment of rupture of the sample. In known tensile testing machines, the most accurate devices for measuring the movement of a moving gripper use mounted electric sensors of small displacements, up to 200 mm, with strain gauge, transformer, capacitive and inductive transducers. However, the use of the aforementioned electric sensors in these machines leads to an increased laboriousness of operation, since the sensors are reinstalled manually by periodically setting their movable elements to the zero position.

A known machine for mechanical testing of materials, in particular tensile, containing a loading device with movable and fixed grips of the test sample, a device for measuring the movement of a movable gripper, which is used as an electric sensor, rigidly connected with a movable gripper, and a loading drive. The electric sensor is made in the form of a housing-coil placed in a pipe mounted on a bed, and a movable core placed inside the coil and mounted on a movable grip. The coil is electrically connected to the measuring unit. During the working course of the movable gripper, the core, that is, the movable element of the sensor, moves relative to the housing, that is, the stationary element of the sensor, from the set zero position and gives a signal about the amount of movement (Testing technique. Reference: in 2 books / Ed. Prof. V.V. Klyueva. - M.: Mechanical Engineering, 1982. - Book 1. - P.86, 107-116, Book 2. - P.387-445).

The disadvantage of this machine is the low accuracy of assessing the mechanical properties of materials at small displacements due to the need to adjust the zero of the electrical sensor during measurement.

The closest analogue to the proposed invention by technical essence is a servo-hydraulic testing machine for mechanical testing of materials, namely, tensile tests, containing a loading device with upper movable and lower stationary grips of the test sample, an electric displacement sensor, rigidly connected by a movable element with a movable gripper through the actuator mechanism for returning the movable element of the electric displacement sensor to the initial zero position and with load drive. The actuator returns the movable element of the electric displacement sensor to its initial - zero - position in the form of a rack gear comprising a gear reducer with an electric motor and a gear rack rigidly connected to the movable element. The loading drive has a servo-hydraulic loading and control system for loading parameters, including a pump unit, which is connected to a servo valve with electrical feedback for movement with an electric displacement sensor, and with a servo valve connected to the lower fixed clamp (patent RU 2158911, IPC ⁷ G01N 3 / 08).

The main disadvantages of a servo-hydraulic testing machine for mechanical testing of materials are the low accuracy of evaluating the mechanical properties of materials due to the use of a complex servo-hydraulic loading system and control of loading parameters, as well as the inability to use the tensile strength for samples of materials of low strength, namely soil, since it fixes the parameters deformation, not rupture of the test sample.

The objective of the invention is to increase the accuracy of the assessment of the mechanical properties of materials and to ensure the possibility of using the proposed machine to determine the tensile strength of materials of low strength, namely soil samples.

The problem is solved in that in the machine for testing soil samples for tearing, containing a loading device with movable and fixed grips of the test sample, an electric sensor associated with a movable gripper and a loading drive, according to the invention, the electric sensor is made inductive, electrically connected to the input to the machine an electronic unit designed to form and measure the bursting force of the sample, which in turn is connected to a load drive, creating a linearly increasing force loading until the sample ruptures.

In addition, to minimize the friction forces, the machine for testing soil samples for breaking is additionally equipped with rolling bearings, which are equipped with a movable gripper.

The possibility of using the proposed machine for determining the tensile strength of materials of low strength is explained by the fact that the introduction of an electronic unit designed to generate and measure the tensile strength of the sample and controlling the load drive allows you to create a linearly growing load force up to the moment of fracture of the material, which is necessary during testing to rupture of soil samples for which fixing the deformation parameters during tensile tests is not possible due to their mechanical properties.

The increase in the accuracy of assessing the mechanical properties of materials is explained by the fact that the moment of rupture of the soil sample is recorded in the absence of measurement error using an inductive electric sensor, regardless of its initial coordinates.

The proposed invention is illustrated in the drawing, where Fig.1 schematically shows a machine for testing soil samples for breaking, side view; figure 2 is the same, a top view; and figure 3 is a functional diagram of an electronic unit intended for the formation and measurement of the tensile strength of the soil sample.

The machine for testing soil samples for tearing contains a loading device, including a bed 1, with an adjustment device 2 to ensure its horizontalness, a movable grip 3 of the test soil sample equipped with rolling bearings 4, and a stationary grip 5 of the tested soil sample, as well as an electrically controlled drive 6 loading, creating a linearly increasing loading force up to the moment of rupture of the sample, mounted on the frame 1 parallel to the power axis of the machine, an electric inductive sensor 7 fixing p rupture of the sample.

The inductive sensor 7 is mechanically connected to the movable gripper 3 and the load drive 6, and electrically to the electronic unit 8, which is used to form and measure the tensile strength of the sample. The electronic unit 8, in turn, is connected to the load drive 6.

The electronic unit 8 contains an automaton 9 with a finite number of states: reset - loading - fixing the force of the gap; an integrator 10 controlled by an automaton 9; the repeater 11, which is switched off by the automaton 9, provides a linearly increasing voltage, its fixation and discharge; a converting signal of the integrator 10 into the loading force through the loading drive 6; a signal converter 12 from the sensor 7; latch 13 of the initial position of the soil sample; a comparison circuit 14, fixing the break of the soil sample when comparing the initial position of the soil sample from the latch 13 and the current signal of the sensor 7 from the Converter 12.

The signal Converter 12 is made in the form of a synchronous detector.

The first output of the machine 9 controls the integrator 10, the second output - the repeater 11, the third output - the lock initial level 13. The output of the integrator 10 is connected to the input of the repeater 11, the output of which is connected to the load drive 6. The output of the signal converter 12 from the sensor 7 is connected to the input of the latch 13 and to the first input of the comparison circuit 14, the second input of which is connected to the output of the latch 13. The output of the comparison circuit 14 is connected to the input of the automaton 9.

The proposed machine for testing soil samples for breaking works as follows. After installing the soil sample in the movable 3 and fixed 5 grippers, the machine is immediately ready to test the sample with the fixation of the zero value at the same time with the lock 13. The electrically controlled loading drive 6 creates a linearly increasing force until the sample ruptures. The moment of rupture is accurately recorded by the inductive sensor 7 for fixing the rupture of the sample, and using the automaton 9, the integrator 10 remembers the force acting at the moment of the rupture, and the repeater 11 controlled by the automaton 9 removes the loading force from the movable gripper 3 after the rupture.

Thus, the use of the proposed machine for testing soil samples at break allows you to expand the range and improve the accuracy of measurements.

Claims (2)

1. A machine for testing soil samples for tearing, comprising a loading device with movable and fixed grips of the test sample, an electric sensor associated with a movable gripper and a loading drive, characterized in that the electric sensor is made inductive, electrically connected to the electronic unit introduced into the machine, intended for the formation and measurement of the tensile strength of the sample, which in turn is connected to a loading drive, which creates a linearly increasing loading force until the moment the sample breaks . 2. The machine according to claim 1, characterized in that it is additionally equipped with rolling bearings, which are equipped with a movable gripper.

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