SU1686302A1 - Method for determining stresses on a preset land taking into account transverse strain sensitivity of strain gauge resistors - Google Patents

Abstract

The invention relates to the technique of grinding deformations and stresses and is intended to be used in experimental studies of the strength of various types of machines and engineering structures. The aim of the invention is to improve the accuracy of measurements of g count of the influence of transverse strain gages of strain gages. The method of determining stresses consists in orientation of two h-resistors on the object at angles taking into account the transverse strain gages of strain gages.

Description

The invention relates to a technique for measuring strain and stress (strain gauge) and is intended for use in experimental studies of the strength of various types of machines and engineering structures.

The aim of the invention is to improve the measurement accuracy by taking into account the influence of the transverse strain sensitivity of the resistance strain gages.

As is known, the relative elongation in a given direction on the surface of an object is determined by the formula

Ј, FfcCOS V + e / sin f + f vsm (P coscfi (1)

where F, and е „- relative deformations by

os m X and Y,

e, v is the shear strain, cf, is the angle between the axis of the tensorisoregore and the axis A.

The strain gauge signal is proportional to the relative increment of its resistance

J ± R

which is subject to the transverse

stress sensitivity can be written i ak:

R

T

St-, -l-Sn 1nf-, 1, S (F, -r-.SF ,,, i,

Jinn

 1G

the same as -y, -. (3)

l

ide S - strain sensitivity (longitudinal): е, - relative elongation along the axis

strain gauge;

S w, i - transverse strain sensitivity. e ", is the relative elongation in the direction perpendicular to the axis of the tenor resistor

The sum e, + 5р „1 can be considered as some effective elongation.

F, i, e, + Sem. (four)

On the other hand, it is t-.F and some

are used when processing measurement results

.- $ Ј) - .. L ,,,

(five)

OS

oo oo oo tc

It is expressed by the formula (I) and tm by that / HI form ω, but with the value ft, m, - (| 1-f-90- (since tm is the elongation in the direction perpendicular to the axis of the strain resistor) and expressions in (4), let’s shake

 I ,, + --Sin) - | -t, / (birrq: 1- | -ScosJ (f,

 ,,; (1 SKlTKj COM),. (6)

Deformations i- ,. е „and (ГД1 / are connected with stresses а ,, гт„ and ТГц by Hooke's law

n, and G - rp,

(7)

 -

U i,

b

 ups 1 not IKK tnnnye

flpeui ib (7) to (b). GET

", -Ј ((1 - fiS) cos-h :, - (c-5) sm2 (f, aI- | -r.i - u S MT (- i u -Sk os j

- I - 5 sini) (.PMJ t, (8

B

Units to the m fn f (, ("for which the coefficient n (S) at m" turns to zero, i e until ten fopeuiLTOpa does not appear a, i, in which -tariHincM according to (8)

0

five

G

 + SL.

 - F) -g- z-r ill; 2 (5, i I-jiS)

The proposed method allows one to take into account the influence of the total vitality strainer, which improves the accuracy of the extraction results, and to reduce by 1 3 the number of required strain gauges, connecting cables and measuring equipment, which reduces the cost of mounting strain gauges and strain gauges. and connecting wires, the manufacture and operation of measuring apia;) atura, which reduces the labor costs for the preparation and testing of tests and the processing of experimental data

Claims (1)

Invention Formula The method of determining the stresses at a given site, taking into account the transverse strain gauges of the strain gauges, consists in gluing the strain gauges on the object, loading the object by measuring strain, using strain gauges and calculating the stresses, characterized in that, in order to improve the accuracy of measurements by counting the stresses and calculating the stresses, characterized in that, in order to improve the accuracy of measurements by counting the stresses and calculating the stresses, characterized in that, in order to improve the accuracy of measurements by measuring strain, transverse strain sensitivity of strain gauges, use two istor tensor, which when gluing orient under the mly them on the object 4f, arctgVf 1 us i9i t h 1 UI J × 1 (J KO |) HH vpaBHlHUH (9) AKPM pborah, sticking (| x And (f (ten) two general logic codes for i i i with i | x and (| D are the steps in the it.i forms (IDi to the characteristic axis of the object is clearly defined in the form (S) and which and P (.1 T, The call is paBiKH.ie (8) m (and i | -1 | and deciding on ist icthem, but inn 1no a, and t, the most forms for it pt U K NIN Oh, and T ,, /. L K.) to the characteristic axis of the object, and after the measurements of the eformation, the sought-for vectors of the normal a are calculated, and the tangent t ,,, of the stresses on the area perpendicular to the characteristic axis E. V71 : - f and f 2  + t. l 40  i - 1  + i-5) i 1-c5) five where | l - Punch coefficients,  - the ratio of the transverse strain gauge coefficient of 5 „PL to the coefficient of tensity of gravity S, Ј and 6 are the elastic moduli, (i.t-j values of deformations, respectively, in the direction of the characteristic axis and the imprint of it