RU2339927C1 - Device for alternating decaying load tests - Google Patents

Abstract

FIELD: mechanics, physics.

SUBSTANCE: device designed to carry out alternating decaying load tests incorporates a pressure chamber with a bore accommodating a piston reciprocating in the aforesaid chamber and held on its initial position, a compressed air source communicating with the said chamber via a controlled valve. Note that the said pressure chamber represents a closed design with the aforesaid piston housing an object to be tested being arranged on the controlled valve side. Note also that the piston is furnished with a retainer to be broken at a preset air pressure.

EFFECT: wide frequency range, chances of simulating alternating decaying loads approximating to actual loads.

1 dwg

Description

The invention relates to testing equipment, namely, bench equipment designed for the study of automation system devices for resistance to shock pulses, causing fading reciprocating movement of their supporting structures.

A known bench for testing products for alternating loads, containing a base with rails installed in the guides of a movable platform for mounting the test product, located on opposite sides of the platform and interacting with it, a hammer and a movable buffer mass, an elastic element fastened to the buffer mass from the platform side with a platform, and a device for accelerating the striker (see A.S. No. 690352, IPC ⁶ G01M 7/00, 1979, "Stand for testing products for alternating loads", published in BI No. 37 dated 10/05/79).

However, such a stand does not allow to obtain an oscillatory process with a given amplitude, frequency and the required damping decrement of these oscillations.

The closest in technical essence to the claimed device is a stand for testing products for impact, taken as a prototype, containing a pressure chamber, freely mounted in it firing pin, and in the chamber there are holes for pressure relief from the chamber for a given movement of the firing pin, table for fixing the subject object, equipped with a hard place impacting the striker, and means for holding the striker in its original position (see AS No. 813159, IPC ⁶ G01M 7/00, 1979 "Stand for testing products on impact", published in BI No. 10 from 03/15/81 g.).

This device does not allow to obtain an oscillatory process, and therefore, to provide alternating load on the test object.

The problem to be solved is the creation of a device for testing products under the influence of alternating decaying load, which imitates real conditions with the greatest accuracy.

EFFECT: obtaining an oscillatory process of loading products, creating alternating decaying loads that are as close as possible to those actually existing in a fairly wide frequency range.

The technical result is achieved in that the device for testing products for alternating decaying loads contains a pressure chamber with holes in which a piston is held in its original position with the possibility of reciprocating movement in this chamber, a source of compressed gas connected to the pressure chamber through a controlled valve. What is new is that the pressure chamber is closed, and the piston with the test object placed in it is mounted on the side of the controlled valve.

Due to the fact that the pressure chamber is closed, the piston receives the possibility of oscillatory movements after an impulse action from the source of compressed gas through a controlled valve. The holes in the pressure chamber provide the ability to control the attenuation intensity of these oscillatory movements, i.e. the attenuation decrement, and the placement of the test object directly in the piston, which is installed on the side of the controlled valve, allows this object to be able to perform reciprocating movements with the piston, while obtaining the required loads.

The drawing shows a diagram of a device for testing products for alternating damping loads.

The device comprises a piston 1 with a cavity 2 in which the test object 3 is placed, a closed pressure chamber 4 with holes 5, as well as a source of compressed gas 6, a controlled valve 7 and a holder 8 of the piston 1 in the initial position.

A device for testing products for alternating damping loads works as follows.

Compressed gas from the source 6 enters through a controlled valve 7 into the pressure chamber 4, in the so-called pre-piston space. After the force of air pressure on the piston 1 reaches a value at which the tensile strength of the holder 8 occurs, the latter collapses and the piston 1 with the test object 3 installed in it begins to move along the pressure chamber 4 with acceleration, changing according to a law close to sinusoidal. At the same time, at a certain point in time, the piston 1 blocks the openings 5 and from that moment the energy of movement of the piston 1 begins to accumulate in the compressible gas enclosed between the piston bottom 1 and the lower closing part of the pressure chamber 4, and this gas simultaneously plays the role of a braking device. Under the action of elastic forces enclosed in compressed gas between the bottom of the piston 1 and the lower closing part of the pressure chamber 4 (valve 7 should already be closed by this moment), the piston 1 begins to move in the opposite direction, trying to occupy a position close to the original, and compressing in this case, the remaining gas in the volume between the top of the piston 1 and the upper closing part of the pressure chamber 4. After reaching a pressure in this volume of a certain value (just like at the previous time in the volume between the bottom of the piston 1 and the lower circuit the other part of the pressure chamber), the piston 1 again begins to move in the forward direction. Thus, free oscillations of the piston arise, the amplitude of which gradually decreases, due to a gradual decrease in the amount of gas on both sides of the piston, and the cycle will continue until the alternating pressure is still possible, first in the volume between the piston bottom 1 and the lower closing part pressure chamber, and then between the top of the piston 1 and the upper trailing part of this chamber, etc. In this case, a multi-cycle alternating decaying loading of the test product 3 located in the cavity 2 of the piston 1 is reproduced. The amplitude and frequency of loading are changed by varying the parameters: tensile strength of the holder 8, mass of the piston 1 together with the test product 3 and the length of the pressure chamber. The damping decrement of these oscillations in a fairly wide range is regulated by changing the parameters of the holes 5.

Thus, the parameters of the holder 8, piston 1 together with the test object 3, as well as the pressure chamber 4 and the holes 5 allow a wide variation of the parameters of the reciprocating movement of the piston with the test object installed in it, thereby realizing almost the entire possible spectrum of alternating decaying loads. At the same time, due to the simplicity and rigidity of the structure, stability and reliability of its operation is ensured.

Computer simulation of the loading process (without taking into account the influence of the hole parameters) allows us to assume that the expected nature of the process is fully consistent with what is required and has ample opportunity to adjust all the most important parameters of alternating loading necessary to ensure completely objective testing of products for alternating decaying loads.

Claims (1)

A device for testing products for alternating damping loads, containing a pressure chamber with holes, in which a piston is held in its original position with the possibility of reciprocating movement in it, a source of compressed gas connected to the pressure chamber through a controlled valve, characterized in that the pressure chamber made closed, and the piston with the test object placed in it is installed on the side of the controlled valve, while the piston is equipped with a holder made with the possibility of violation at a predetermined air pressure force.