SU1413478A1 - Apparatus for cyclic loading of specimens - Google Patents

Abstract

This invention relates to a mechanical testing technique by cyclic loading of specimens. The purpose of the invention is to improve the dynamic characteristics by reducing the mass and moment of inertia of the vibration exciter, as well as expanding the functionality by loading with cyclic torsion and bending with adjustable axial force. Sample 11 is dispersed perpendicularly to the axis of shaft 6 of vibration exciter 5 in the middle between the rotational planes of unbalance 7 and 8, Grip 2 is connected to shaft 6, during rotation of which the sample is loaded with 1-fold twisting and bending moments and a cycle axial force. When the shaft interacts with double-sided adjustable lugs 12 and 13, the axial force is completely or partially perceived by them. When the axial load is completely removed from the sample by lugs 12 and 13, the sample is loaded with cyclic bending and twisting g moments of about 1 Goa L-ly, 2 or more. (L

Description

Fig.G

The invention relates to a mechanical test technique, in particular to devices for cyclic loading of specimens.

The purpose of the invention is to improve the dynamic characteristics by reducing the mass and moment of inertia of the vibration exciter, as well as expanding the functionality by providing loading with cyclic torsion and bending with a controlled non-cyclic axial force o

Fig, 1 shows a diagram of the device; in fig. 2 shows a loading pattern of a sample; The device comprises a pair of coaxial grippers 1 and 2, one of which is connected to the base 4 via a dynamometer 3; and the other with a single-shaft debalance exciter 5. The latter is a shaft 6, on which unbalances 7 and 8 are placed, the centers of gravity of which are in the same plane with the axis of the shaft 6. In this case, the unbalances 7 and 8 can be located on either side shaft (phase shift TG) and one (phase shift. O), Levers 9 and 10 unbalances 7 and 8 perpendicular to shaft axis 6. Sample 11 is connected by gripper 2 with vibration exciter 5 and is installed perpendicular to shaft axis 6 symmetrically with respect to the planes of rotation of the unbalances 7 and 8, Adjustable two The external stops 12 and 13 are connected to the exciter 5 and are installed parallel and symmetrically about the axis of the sample 11,

The device works as follows.

During the rotation of the unbalances 7 and 8, a circular force P is applied, applied in the XY plane at the point O, and the circular moment M in the plane of the shaft axis 6 and the unbalances 7 and 8.

The circular force P loads the sample by harmonically varying cantilever bending in the XY plane:

20

35

The circular moment M loads the sample with harmonically varying steep - we seek moment

 M, amrwHl + - cos6Jt (2)

 m;,

and creates a bending moment in the X plane:

M, am. +) sin6Jt,

m

perceived by adjustable stops 12 and 13.

Sample 11 is loaded with in phase harmonically varying bending (1) and twisting (2) moments:

M

M

.... bm.2w4l + -) coswt;

I5G1. jj

, n am. 2W (1+ -) costJt. P m,

(3)

Depending on (3) in parentheses, the upper sign corresponds to the position

25 unbalances in opposite directions (phase shift 1), and the lower sign in one direction (phase shift 0). If t and unbalances

 arranged in one direction

Sn (phase shift 0), then cyclic loading is performed only by bending. If m.j t and unbalances are located in opposite directions (phase shift u), then torsional cyclic loading is performed.

When the axial load is fully perceived by the lugs 12 and 13, it performs-d0 with loading only by bending with torsion.

Claims (1)

1. A device for cyclic loading of samples, containing a base, a single-shaft unbalance exciter in the form of two parallel levers fixed to ONE shaft perpendicular to its axis with unbalance and two coaxial grips, the first is gripped by a dynamometer with the base, and the second with a shaft of a vibration exciter, characterized in that, in order to improve the dynamic characteristics by reducing the mass and moment of inertia of the vibration exciter, the axis of the grips is perpendicular to the axis of the shaft, and the second gripper is located at the same distance from the axis of the levers. 2, the device according to claim 1, characterized in that, in order to extend the functionality by providing loading with cyclic torsion and bending with an adjustable magnitude cyclic axial force, it is equipped with two parallel axes of the grippers with adjustable double-sided stops designed to interact with the shaft of the vibration exciter. th)