Měření zbytkové napjatosti metodou uvolňování sloupku: Analýza kalibračních koeficientů pro metodu přírůstku deformace

Ring-Core Residual Stress Measurement: Analysis of Calibration Coefficients for Incremental Strain Method

journal article - other

en

Correctly determined and properly used calibration coefficients for a residual stress measurement by ring-core method (RCM) are essential. Knowledge of their dependence on the disposition of residual state of stress cross the depth of metallic material gives results correspond of theirs appropriate application. In this article, incremental strain method (ISM) is used for determination of the calibration coefficients K1 and K2 under uniaxial and biaxial state of stress conditions. Finite element method (FEM) has been used in order to calculate relieved residual strains on the top of the core. Calculated calibration coefficients are plotted on graphs in dependence on the drilled depth and character of the residual stress state. Appropriate polynomial functions have been interposed by these points. We conclude that values of calibration coefficients K1 and K2 determined by the incremental strain method can be used only for homogenous residual states of stress. Examination of linearly varying state of stress indicates inaccurate results increasing with the depth of drilled groove.

Článek se zabývá analýzou kalibračních koeficientů pro pro vyhodnocení homogenního pole napjatosti po hloubce odvrtaného materiálu. Koeficienty jsou určeny pro metodu přírůstku deformace, pomocí které lze stanovyt velikosti a směry halvních zbytkových napětí.

Correctly determined and properly used calibration coefficients for a residual stress measurement by ring-core method (RCM) are essential. Knowledge of their dependence on the disposition of residual state of stress cross the depth of metallic material gives results correspond of theirs appropriate application. In this article, incremental strain method (ISM) is used for determination of the calibration coefficients K1 and K2 under uniaxial and biaxial state of stress conditions. Finite element method (FEM) has been used in order to calculate relieved residual strains on the top of the core. Calculated calibration coefficients are plotted on graphs in dependence on the drilled depth and character of the residual stress state. Appropriate polynomial functions have been interposed by these points. We conclude that values of calibration coefficients K1 and K2 determined by the incremental strain method can be used only for homogenous residual states of stress. Examination of linearly varying state of stress indicates inaccurate results increasing with the depth of drilled groove.

kalibrační koeficienty, metoda přírůstku deformace, zbytkové napětí, metoda uvolňování sloupku, tenzometrická růžice

calibration coefficient, incremental strain method, residual stress, ring-core method, strain gauge

2011

31.01.2011

1801-1217

Bulletin of Applied Mechanics

6

24

77–82

5