SU1455277A1 - Installation for testing specimens in cyclic loading - Google Patents

Abstract

This invention relates to fatigue testing of specimens. The purpose of the invention is to enhance the functionality by providing bending with torsion with changing the components of the load during the test by changing the relative orientation of the shafts. Sample 3 set in coaxial grippers. The drive d the rotation of the depressions 5 and 6 with equal static moments, loading the sample with bending load and torque. During the testing process or before its beginning yrori displacement between shafts 8 and 9, the bending and torsion components change. 2 Il.

Description

yy

SL SL

ND 1

/

Phi.1

The invention relates to tests, in particular to installations for fatigue testing of specimens for bending and

torsion.

The purpose of the invention is the expansion of rational possibilities due to the curvature of the liver with torsion with a change in the process of testing the composition of the load by changing the ratio Q

shaft orientation.

Figure 1 presents the setup; figure 2 is a diagram of the orientation of the unbalance.

The installation for testing samples 15 under cyclic loading contains an engine 1, coaxial grippers and a two-chamber double-balancer vibration exciter 2, with which one of the grips for sample 3 is connected. The installation is equipped with an angular displacement mechanism 4 for changing the orientation of unbalances 5 and 6, which are installed with the possibility of rotation in the plane, perpendicular to the p-25 axis of the grippers. The input shaft 7 of the mechanism 4 is connected to the engine 1, and the output shafts 8 and 9 - with the shafts 10 and

11vibrovozbuditel 2.

Mechanism 4 consists of two identical parts. FIG. 1 shows only one part of the mechanism 4 with the output shaft 8 (the other identical part of the mechanism 4 with the output shaft 9 is not shown in FIG. 1) .., g

Mechanism 4 contains two hollow shafts

12 with gears 13, connected by a parasitic gear

14, clutch 15, return spring 16 with plunger 17 to move the plug 18 40 with clutch 25 from the cam profile 19. Spring 20 allows the sample 3 to be loaded with a static torque that is measured by a dynamometer 21. Second gripper ,. A coaxial gripper, 1 45 tu of the vibration exciter, is connected to the base 22 via a dynamometer 21.

The installation works as follows.

Sample 3 is set in grips and unbalances 5 and 6 are rotated in the same direction with the same angular velocity. When the coupling 15 is axially displaced, the relative angular displacement of the hollow 55 shaft 12 and the input shaft 7 is displaced by an angle O - L / 2 in different directions of both parts of the mechanism 4. The coupling 15 is moved by the plunger 17 from

A rotating profile cam 19, allowing one or another periodic law of load variation during testing. The return spring 16 moves the plug 18 with the coupling 15 in the opposite direction. The rotation of the imbalance 5 and 6 is transmitted by the output shafts 8 and 9. The change is ugg; The displacement between shafts 8 and 9 allows the ratio between the torsional and flexural components of the load to change both before and during the test.

With a relative displacement of the shafts 8 and 9 by an angle d, rotating in one direction, the bending force, the torque, M, is determined from the following relations

Izg

2P cos „/ 2,

M “R.a sin eJo / 2 sin (wt ol2)

where P is the centrifugal force of the rotating

vibrator mass, kg; “C is the angular displacement of masses; a is the distance between the axes of the rotating unbalances, cm; W - circular frequency of rotation

masses, 1 / s; t - time, s.

These hangings show that the test sample is acted on a constant magnitude rotating vector with angular velocity w and a harmonic variable with angular velocity w angular velocity

MKPV in particular, the following types of loading are implemented (about 0; 2P; μR About circular bending along a symmetrical cycle; and P

U (c R.a -cos ou t

Jfsr t

variable torsion on a symmetric cycle; clg 2j

RIEG M „p-1Ж P, asin () - circular bend with variable torsion

Claims (1)

Invention Formula A unit for testing samples under cyclic loading, containing a base, coaxial grippers for a sample, one of which is connected to the base, and a two-chamber two-balance vibration exciter associated with the second gripper, the debalans of which have equal static moments, and are installed with the possibility of rotation in one plane, perpendicular to the axis of the grips, characterized 14552774 so that, in order to expand; - - - .., .-, t c iiuiu a4 shirenil. functionality due to the provision of bending with torsion with a change in the process of testing the composition relative to the orientation of the shafts, equipped with an angular spacing mechanism. Editor I. Casard Compiled by D. Pospelov Tehred M. Didyk Proofreader L. Pilipenko Order 7450/51 Circulation 788 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, st. Project, 4 relative orientation of the shafts, it is equipped with a mechanism of angular displacements of the shafts. Subscription