SU1631352A1 - Fatigue testing of structures in centrifugal field - Google Patents

Abstract

The invention relates to testing, in particular to devices for fatigue testing in a field of centrifugal forces. The purpose of the invention is to increase the reliability of determining the fatigue characteristics of turbomachine disks by approximating the cycle parameters to operational ones. Engine 1 rotates structure 3, transmitting movement through shafts 11 and 15, connected by a planetary mechanism 4. Wheel 6 is connected to shaft 11, and wheel 7 is connected to a planetary mechanism 4. Wheels 6 and 7 are connected by a full turn crank-and-crank mechanism backstage, which allows rotation with a cyclic change in the rotation speed with a wide variation of the cycle parameters, 3 sludge. with $ (L

Description

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The invention relates to devices for fatigue testing of structures in the field of centrifugal forces.

The purpose of the invention is to increase the reliability of determining the fatigue characteristics of turbomachine disks by approximating the cycle parameters to operational ones.

Figure 1 shows the device; figure 2 is a view of And figure 1; Figure 3 shows the time variation of the loading frequency.

The device comprises a drive motor 1, a base in the form of a housing 2, an object of testing — a structure 3 installed in a gripping device (not shown), a planetary mechanism 4, and gear wheels 5-10, mounted respectively on shafts 1 1 15. Shaft 11 is the first (input) drive shaft of rotation, and the shaft 15 - the second (output) drive shaft. At a distance r from the axis on the wheel 6, a pin 16 is fastened, which fits into the groove 17 of the wheel 7. The axles of the wheels 6 and 7 are shifted to the value. The number of teeth of the wheels 5-10 are respectively Zf - Z.

The device works as follows. /

The gear wheel 5, which rotates together with the shaft 11 at a constant angular velocity of the engine gearbox, is engaged with the gear wheel 6, which takes part of the power flow. At a distance r from the axis on the wheel 6, the pin 16 is fixed, aligned with the radial through groove in the wheel 7 (type A). The wheels 6 and 7, whose axes are displaced by the value of t, together with the finger 5, form a device with a harmonically varying gear ratio — a crank-and-rocker mechanism with a full turn of the link (g $). The angular velocity of the wheels 6 and 7, respectively, are equal to

Z

C0g dv const;

m ri cos (() W Lg l-hnZ; -2mcos (CO, t)

where m

i 1.

Thereafter, a flow with a harmonically variable transmission ratio through the gears 10 and the planetary gear 4 is connected at the output shaft 15 with the main flow. The angular velocity of the test object, mounted on the shaft 15, can be expressed by the following function of time

UOB with ° Aw

{

1 + z

7 1-со со8 (CODY - Zi Z3 z. In Z a

t)

Z2 / Z4 Z 6

1 + m2 -2m costto 1 t).

The parameters of the cycle (Fig. 3) can be determined by the following relationship m.

2ft Z2.

WITH

Max

ABOUT

 WITH

 AB

ZX ... z.v,

Z2-Z4-Z6

z,

and

™.) J.

(1 +

Change -, 0) AL and m, you can adjust

g

 A &

five

0

five

To cycle parameters in a wide range.

The device can be provided for smooth regulation of the angular velocity of the engine within 50 - 500 rad / s and the parameter m in the range of 0.05-0.4.

Due to the application of the proposed device, it is possible to realize a loading cycle of less than 2 s, which corresponds to the operating conditions of diets of turbomachines. In addition, the durability of an electric motor operating in this case at a constant speed is increased.

Claims (1)

Invention Formula A device for fatigue testing of structures in the field of centrifugal forces, comprising a base, an engine mounted thereon, a rotation device associated with it, a gripping device associated with the latter, and a device for cycling the rotation speed of the gripping device. devices that differ, in order to increase the reliability of determining the fatigue characteristics of turbomachine disks by approximating the cycle parameters to operational ones, the rotational drive is made in the form of two shafts connected by means of a planetary mechanism, the first of which is connected to the engine and the second with gripping device but) (J.  Food (J  lshn and the device for cycling the rotational speed of the gripping device is made in the form of wheel sets mounted on the basis of two non-axial, connected by means of a full-turn crank mechanism, the first of which is connected to the first rotational drive shaft and planetary mechanism. sixteen FIG. 2 Fig.Z