SU1567904A1 - Resonator for vibration-testing machine - Google Patents

Abstract

The invention relates to a vibration test technique and extends the operational capabilities of a resonator by increasing the range of control of the asymmetry factor of the oscillation cycle. A resonator made in the form of a beam with a central branch and side branches symmetrically located relative to the longitudinal axis of the beam is equipped with a device for deforming the side branches. This device contains two inserts between the central and side branches of the insert 6, 7, one end of each of which contacts the side edge of the central branch, screws 9, 10 screwed into inserts, which contact the ends with the side edges of the central branch, and supports 11, 12 located on the side branches x between the corresponding screw and the point of contact of the liner with the side face. The bending stiffness of each liner in the plane of deformation of the side branch is higher than that of the side branch. Due to the change in the angular position of the liners and the efforts of deforming the side branches, the coefficient of asymmetry of the cycle can be adjusted in the range from -1 to 0. 5 ill., 1 tab.

Description

Fig.Z

The invention relates to a testing technique, in particular, to vibration testing of products, in particular to resonators for shakers, providing an asymmetric oscillation cycle with an adjustable cycle asymmetry factor.

The purpose of the invention is to expand the operational capabilities by increasing the range of control of the asymmetry coefficients of the oscillation cycle

FIG. 1 shows a resonator, top view; FIG. 2 - the same, side view; in fig. 3 is a section A-A in FIG. 1, FIG. 4 is a diagram of the forces acting in the contact of the inclined insert with the support when the central branch of the beam moves down, in FIG. 5 the same, when the central branch of the beam moves up.

The resonator contains a beam with three parallel branches: the central branch 1, on which the product under test (not shown) is installed, and the side branches 2 and 3 symmetrically located relative to the longitudinal axis of the resonator. The ends of the beam have support lugs 4 with holes 5 for bolts, Serves for mounting the beam on the shaker table (not shown) To create an asymmetric oscillation cycle, the resonator is equipped with a device for deforming the side branches 2 and 3 This device includes two located between the central and lateral The branches of the liner 6 and 7, each of which has an end 8 at the end, which is in contact with the side face of the central branch 1, coaxial screws 9 and 10, which are screwed respectively into the inserts 6, 7 and are in contact with the ends with the side edges of the branch 1, and supports 11, 12 for inserts 6, 7, each of which is located on the side branch 2 (3) between the screw and the point of contact of the stop 8 with the side face of the central branch 1 V side

five

outgoing branches x 2, 3, windows 13, 14 are made through which screws 9, 10 freely pass, and in each of the side faces of the central branch 1 there is a conical recess for the stop 8. The dimensions of the cross section of the beam branches and liners are chosen so that The flexural vibrations of each of the side branches 2 and 3 lie in the resonance region of the flexural vibrations of the central branch 1, and the flexural rigidity of each liner 6 (7) in the plane of deformation of the side branch is higher than that of the side branch 2 (3).

The resonator works as follows

When resonant oscillations of the central branch 1 of the beam relative to the lateral branches 2, 3, it is affected by the force Fv of inertia, the force FTf of friction and the force Fs of elasticity of the side branches, depending on the tightening force of screws 9, 10. The forces Fs have different values in the extreme lower and top polo 0 bride x center branch 1

When the angular position of the liners 6, 7 (i.e., angle a in Figs. 4 and 5) changes, the valve component Fg of the elastic force Fg and the resultant force Fv, F and FЈ change, affecting the deflection of the work branch 1 Equivalent force FI in the lower position F of Fu-2Fj is 2FTf -cosa, and the resultant force FI in the upper position of F2 F is -2Ff-2Frp -cosa (where a is the angle between the side of the liner and the vertical).

The asymmetry factor g of the oscillation cycle is determined by the ratio and can be adjusted from -1 to 0 by varying the deformation forces of the side branches 2, 3 and the angle a. When on the central branch 1, a series of unipolar acceleration pulses is reproduced with an interval between them equal to half the pulse following period.

The calculation of r for some values of a is given in the table below.

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0

The results listed in the table were obtained with the following resonator parameters Material - steel 45, friction coefficient 0.1, maximum acceleration on the working branch with a symmetrical cycle 500 g, width and height of the section of the central branch 60 and 20 mm, respectively, the length of the side branches, width and the height of their sections is 170, 3 and 22 mm, respectively, the mass of the device with the test product, installed on the central branch of 1 kg, the displacement of the supports of the inserts relative to the stops 2 mm.

Claims (1)

Invention Formula A resonator for a vibrostand containing a beam having supporting protrusions at the ends, serving to install it on a vibrostand, and made with three parallel branches so that the natural frequency of bending vibrations of each of the side branches located symmetrically with respect to the longitudinal axis of the beam lies in the resonant region bending vibrations of the central branch, and a device for deforming the lateral branches of the beam, including two coaxially installed screws, the ends of which are in contact with the lateral faces of the central branch of the beam, characterized in that, in order to expand operational capabilities by increasing the range of control of the asymmetry factor of the oscillation cycle, it is equipped with two beams located between the central and lateral branches and the contacting ends with lateral faces of the central branch with inserts into which screws are screwed, and two supports for inserts, each of which is located on the side branch between the screw and the contact point of the insert with the side edge of the central branch, while the flexural rigidity of the insert in the plane of deformation of the side branch is higher than that of side branch. FIG. one Fig l FIG. five I 4 / FIG. Z