RU1810666C - Power absorber - Google Patents

Abstract

Usage: in mechanical engineering for the absorption of kinetic energy during intensive dynamic loading of structures. SUMMARY OF THE INVENTION: An energy absorber comprises a deformable element in the form of a hollow cylinder with annular protrusions on the outer surface uniformly spaced along its length and at the ends. The distance between the annular protrusions is selected from the relation: IK 2,4vRh, where R is the internal radius of the cylinder, h is the wall thickness, and the width and height of the protrusions are chosen to be (1.5-2) h. In addition, the outer surface of the hollow cylinder is made curved with a radius of curvature equal to the distance between the annular protrusions. 1 s.p. 3 ill.

Description

The invention relates to devices designed to absorb kinetic energy under intense dynamic loading of structures. The invention can be used in the development of vehicles with the purpose of protecting them from shock in collisions with an obstacle, in the design of earthquake-resistant structures, as well as in other branches of engineering that are directly related to systems of protection against intense shock loads.

A plastic shock absorber (prototype) is known, comprising a guide rod and a deformable element in the form of a hollow cylinder with evenly spaced annular protrusions on the outer surface 2. The energy is absorbed in it by plastic buckling of the supporting cylinder wall outside. . Such a process is ensured by the fact that the guide rod prevents the development of dents inward, to the center of curvature of the hollow cylinder. In this case, an undesirable effect occurs - friction of an uncontrolled nature between the moving rod and the bulged wall of the cylinder during the operation of the shock absorber, which violates the stability of the device’s performance (force-stroke diagram of the shock absorber), thereby reducing the efficiency of kinetic energy absorption. With a sufficiently thin supporting wall, the bulging of the cylinder is characterized by a non-axisymmetric waveform. In this case, the force-displacement diagram has a drop section after reaching the maximum load, which does not provide the necessary energy consumption of the shock absorber.

The aim of the invention is to remedy these drawbacks - simplifying the design of the energy absorber, reducing overall dimensions and weight, maximizing energy absorption.

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Figure 1 and figure 2 shows the proposed energy absorbers of two types.

In Fig. 3, a load-displacement diagram is presented in the form of a P-A dependence. The energy absorber in the form of a hollow cylinder 1 contains annular protrusions 2 on the outer surface, evenly spaced along its length and at the ends. The distance IK between protrusions 2 is selected from the ratio: U: e2,4vRFr where R is the internal radius of the cylinder, h is the wall thickness. The width o and the height from the protrusions are chosen equal: (1.5-2) l.

The annular protrusions installed in these places prevent the formation of asymmetric dents in a wide range of shock load amplitudes, including a small level of amplitudes when the cylinder wall is sufficiently thin. Due to this, a constant level of braking load is ensured in the ecritical stage of deformation of the hollow cylinder.

Energy absorption with a curved wall (Fig. 2) is made with a radius of curvature p equal to the distance (1k1 between the annular protrusions).

The energy absorbing device is turned on when the loading object strikes the end of the hollow cylinder I. In the process of loading with the force P, the energy absorber goes through three stages in turn: elastic deformation se due to iocrmic compression of the hollow cylinder (direct ascending section on the P-A dependence curve , FIG. 3), the loss of stability of the cylinder wall at a critical value of the axial force P (end of the ascending section — the beginning of the horizontal section 3 of the curve of the dependence P-A in FIG. 3), plastic deformation with axisymmetric bulging out in a supercritical stage

(horizontal section 3 in FIG. 3). The damping ability of the energy absorber is provided in the last two stages, when the axial force reaches a critical value P (response threshold).

The proposed ratio for the location of the protrusions (annular stiffeners) determine the nodal sections

sinusoidal axisymmetric

bulging and thereby provides

the formation of outer annular bulges in the supporting wall of the cylinder, which finds expression in the development of plastic

buckling at a constant load level.

The energy absorber is installed in

the space between the protected object and the loading device, for example

in the bumper supports of vehicles.

Formula of the invention

Claims (2)

1. An energy absorber containing a deformable element in the form of a hollow cylinder with annular protrusions on the outer surface uniformly spaced along its length and at the ends, characterized in that, with the aim of absorbing anergy and simplifying the design, the distance is 1k between the annular protrusions selected from the ratio iKs2,4VRh, where R is the internal radius of the cylinder; h is the wall thickness and the width and height of the protrusions are selected equal to (1.5-2) h. 2. The energy absorber according to claim 1, about t l and chayu and s; the fact that the outer surface hollow cylinder is made curved with a radius of curvature equal to distance between annular protrusions. f A & ЈS.3 I l