UA60875A - Device for generating dynamic loads - Google Patents

Abstract

The proposed device for generating dynamic loads contains a sectioned cylindrical element, in which lower section a plunger chamber with a plunger and a gunpowder pressure accumulator are installed, and shock-absorbers. The lower section of the cylindrical element is designed as a telescopic construction, which provides the possibility of the displacement of the lower section relative to the adjacent section as well as the possibility to interact with the shock-absorbers.

Description

Description of the invention

The invention relates to testing equipment, and more specifically to shock test stands and 2 can be used for testing objects under the action of dynamic loads in the form of linear accelerations.

A dynamic load generator is known, which contains a cylinder, a piston with a seal, forming a piston chamber with the bottom of the cylinder, and powder pressure accumulators connected to the piston chamber (see patent

of Ukraine Mo54188A, IPC 501M7/00, 2002). The well-known dynamic load exciter is intended for testing objects under the action of linear accelerations with a constant value, for which a constant pressure is maintained in the piston chamber 70. Working pressure is created by powder pressure accumulators (PATs), which are ignited sequentially.

But during the ignition of the powder charge of each PAT (especially the first) and with a small volume of the piston chamber, a high pressure peak is created, the value of which significantly exceeds the working pressure (see the book

V. I. Feodosyev and G. B. Sinyarev "Introduction to rocket technology", M., "Oborongiz", 1960, p. 219, fig. 5.21, graph 12 IP). As a result, the loads acting on the test object exceed the calculated ones and will lead to its destruction, which is undesirable.

Reducing the pressure peak is achieved by significantly increasing the initial volume of the piston chamber, which is filled with air. But there is a large amount of oxygen in the large volume of air in the piston chamber. During the ignition of the first PAT, combustion products enter the piston chamber, along with which particles of solid fuel that have not burned are carried out. As a result of this, unsteady processes of afterburning of the specified particles of solid fuel in the oxygen of the air take place in the piston chamber. This leads to a significant increase in pressure and deviation of the value of the dynamic load from the calculated one. In addition, during the combustion of the powder charge, combustion products are created, which include CO, H 5 , С and others (see the book by Y.M. Shapiro, G.Yu.

Mazing, N.E. Prudnikov "Theory of a rocket engine on solid fuel", M., "Voenizdat", 1966, p.32). In the volume 22 of the piston chamber, which is increasing, conditions are created (high temperature, pressure, a certain ratio of the mixture of the specified combustion products with air oxygen), in which their rapid afterburning occurs, that is, the phenomenon of an explosion occurs. As a result of this, the value of the dynamic load increases sharply (up to 2 times), that is, the impact phenomenon occurs, as a result of which the object being tested is destroyed.

The cylinder is made in the form of separate sections, which are connected using a device according to the patent of Ukraine under the application Mo2002075462 of July 3, 2002, IPC P16835/04. rch-

The disadvantage of the well-known dynamic load exciter is its low operational qualities, such as: - a large volume of the piston chamber to ensure the ignition of the first PAT, which significantly increases the size and weight of the exciter; o - the presence of afterburning of solid fuel particles and combustion products in the piston chamber during ignition

From the first PAT, which leads to the destruction of the object being tested. at

The closest to the proposed technical solution is the dynamic load exciter selected as a prototype, which is described in the author. St. USSR Mo1419286, IPC z01M7/00, 1987. The specified dynamic load generator contains a sectional cylinder, on the lower section of which a piston and a bottom with PATs are installed to form a piston chamber, and an elastic membrane and a collector are attached to the piston. The presence of an elastic Z 70 membrane eliminates the process of afterburning of solid fuel particles and combustion products by removing air from the piston chamber through the collector, as a result of which the accuracy of dynamic load reproduction increases. Shock absorbers in the form of hydraulic cylinders are used to ensure piston braking. St. USSR Mob 90351, IPC 501М7/00, 1979 Or.

The disadvantage of the well-known dynamic load generator is its poor performance due to the presence of an elastic membrane, because it quickly burns out and requires a time-consuming operation to replace it. aw! The invention is based on the task of creating an improved dynamic load exciter, which would ensure an increase in its operational qualities by introducing new elements and technical solutions into it, such as: - and 20 - the lower section of the cylinder is made telescopic with the possibility of movement along its adjacent section, which allows to ensure a sufficient volume of the piston chamber before the ignition of the second PAT due to the use of pressure energy of the combustion products of the first PAT; - the piston is installed on the adjacent section of the cylinder, which makes it possible to exclude uncalculated movement of the piston with the object in the process of moving the lower section; 29 - the piston and the bottom are located equidistantly, which allows to minimize the volume of the piston chamber and in. the amount of oxygen she has; - the lower section of the cylinder is made with the possibility of interaction with shock absorbers, which makes it possible to exclude the deformation of the lower section of the cylinder and ensure its multiple use.

The task is solved in such a way that in the proposed dynamic load exciter, 60, which contains a sectional cylinder, on the lower section of which a piston and a bottom with powder pressure accumulators are installed to form a piston chamber, and shock absorbers, in it the lower section of the cylinder is made telescopic with the ability to move along of its adjacent section and interaction with shock absorbers, and the piston is installed on the adjacent section of the cylinder, while the piston and the bottom are equidistant.

To explain the proposed invention, drawings and its detailed description are attached. The drawings show:

- in Fig. 1 - a general view of the driver of the dynamic load (before the ignition of the first PAT); - in Fig. 2 - a general view of the driver of the dynamic load (before the ignition of the second PAT).

The proposed dynamic load exciter consists of a cylinder 1 with a bottom 2, a piston 3 formed by a bottom 2 and a piston from the piston chamber 4 and connected to the piston chamber 4 PAT 5 and the main PAT 6. The bottom 2 is installed on the lower section 7 of cylinder 1, and the piston C is installed on the frame 8 of the adjacent section 9 of the cylinder 1. The cylinder 1 is fixed with a pin 10, and the lower section 7 interacts with the hydraulic cylinders 11 of the shock absorbers and the hydraulic cylinders 12 of the drive, which are evenly located around the lower section 7. To transfer the dynamic load that is formed to the test object 13 serves as a 7/0 platform 14, which is mounted on the piston 3. A transverse (radial) support 15 is installed on the test object 13 or platform 14.

The work of the dynamic load exciter is carried out as follows.

PATs 5 and 6 are mounted on the bottom 2 of cylinder 1, the powder charges of which have the specified consumption characteristics (Fig. 1). Due to the fact that the bottom 2 and the piston C are equidistant, the piston chamber 4 has a small volume /5 With a small amount of air oxygen.

Then they ignite PAT 5 blowing with little consumption of combustion products. Combustion products enter the piston chamber 4 and create intermediate pressure, under the influence of which the lower section 7 with the bottom 2 goes down and is braked by the hydraulic cylinders 11 (Fig. 2). Due to the fact that there is a small amount of oxygen in the piston chamber 4, as a result of the afterburning process, the pressure in the piston chamber 4 changes little.

Then the main PAT 6 is ignited with a large consumption of combustion products. Combustion products enter the large volume of the piston chamber 4 and create working pressure, under the influence of which the piston C with the platform 14 and the object 13 moves up with a constant amount of acceleration.

After the tests, the piston C is lowered onto the frame 8, and the lower section 7 is lifted up with the help of hydraulic cylinders 12.

In order to exclude a sharp increase in pressure in the piston chamber 4 during the ignition of each of the burners b5 and b and smooth acceleration of the test object 13 to the calculated acceleration value, the volume of the piston chamber 4 " is selected from the following half-ratio: mio x02-04, where mi - working volume at the moment of ignition of the i-th PAT, m; at

From seg - the initial weight consumption of combustion products of the i-th PATAa, kgf/s. in.

For tests of heavy objects with an overload, the value of which exceeds 4-6 units, the following ratio should be observed: o

Rem Okh 40- VO, (Se) where P is the total weight of the test object and the piston, ts.

The proposed dynamic load exciter can provide testing of the propulsion unit compartment according to Ukrainian patent Mo49724A, IPC 864(01/00, g42815/00, 2002), which has a weight of 5 tons and a diameter of Zm.

Thus, the proposed dynamic load exciter, which has a simple and reliable design, allows you to eliminate the distortion of the dynamic pulse that is formed and increase the reliability of the test results.

Claims (1)

;" The formula of the invention (22) Dynamic load generator containing a sectional cylinder, on the lower section of which a piston and a bottom with powder pressure accumulators are installed to form a piston chamber, and shock absorbers, which is distinguished by the fact that the lower section of the cylinder is made telescopic with the ability to move along 5p of its adjacent section and interaction with shock absorbers, and the piston is installed on the adjacent section of the cylinder, while the piston and the bottom are equidistant. sl R 60 b5