| 摘要 |
The application of the orifice relaxation method using existing 3-band rosettes requires a perfect centring of the orifice and the precise determination of its radius. Eccentricities of as little as 1 mm may give rise to errors of 40% in the maximum principal tension. With the new 6-band rosettes (Fig. 1) or the 5-band variant (Fig. 2), equivalent centring deformations are calculated that are sufficiently approximate for division, by 5 or 3 respectively, of the corresponding errors in the 3-band rosettes. Moreover, using the computational method and the software developed for this purpose, the new rosettes enable the principal tensions and their direction to be determined with practically zero error in eccentric orifices, without the need to measure eccentricity parameters. With 6-band rosettes determination of the radius of the orifice is omitted.
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