Určení zbytkové napjatosti metodou vrtání otvoru pomocí příčinkové funkce

The residual stress determination by the hole drilling method by means of the influence function

conference paper

en

The hole drilling method is widely used for residual stresses measurement. The evaluation of the inhomogeneous residual stresses through the depth can be performed by the integral method or power series method. The calibration coefficients are necessary to determinate by the finite element method for each method separately. The determination of the calibration coefficients takes usually much time. The generally view of the residual stress determination gives the influence function. The problem of the influence function solved Beghini (2000). The calibration coefficients for the integral method and for the power series method and for an arbitrary new method can be determined by the influence function. The base of the integral method consists in the approximation of the residual stress by a piecewise constant function. The base of the power series method consists in the approximation of the residual stress by a polynomial function. The new method would be consisted in an approximation of an arbitrary function. In this paper the influence function is determined for the strain gauge rosette RY 61 S. Then the influence function is used for the residual stress determination. Further the calibration coefficient of the integral method was compared with the calibration coefficients determined by the influence function which was provided with kindness by M. Beghini from University of Pisa, Italy.

Metoda vrtání otvoru je široce užívaná pro měření zbytkové napjatosti. K vlastnímu výpočtu zbytkových napětí existuje několik procedur. Nejznámějšími procedurami jsou integrální metoda a metoda mocninných řad. Před vlastním použitím jednotlivé metody je nutno určit její kalibrační koeficienty nejlépe metodou konečných prvků, což je obvykle značně časově náročné. Obecný pohled na výpočet zbytkových napětí metodou vrtání otvoru za dodržení základních předpokladů přináší zavedení příčinkové funkce. Pomocí této příčinkové funkce mohou být jednoduše stanoveny kalibrační koeficienty jak pro integrální metodu, pro metodu mocninných řad, tak i pro libovolnou "novou" metodu. Tato nová metoda by spočívala v aproximaci zbytkových napětí libovolnou funkcí, nejen po částech konstantní funkcí – jak je tomu u integrální metody – nebo mocninou funkcí – jak je tomu u metody mocninných řad. V tomto příspěvku je stanovena příčinková funkce a je použita pro určení zbytkové napjatosti.

The hole drilling method is widely used for residual stresses measurement. The evaluation of the inhomogeneous residual stresses through the depth can be performed by the integral method or power series method. The calibration coefficients are necessary to determinate by the finite element method for each method separately. The determination of the calibration coefficients takes usually much time. The generally view of the residual stress determination gives the influence function. The problem of the influence function solved Beghini (2000). The calibration coefficients for the integral method and for the power series method and for an arbitrary new method can be determined by the influence function. The base of the integral method consists in the approximation of the residual stress by a piecewise constant function. The base of the power series method consists in the approximation of the residual stress by a polynomial function. The new method would be consisted in an approximation of an arbitrary function. In this paper the influence function is determined for the strain gauge rosette RY 61 S. Then the influence function is used for the residual stress determination. Further the calibration coefficient of the integral method was compared with the calibration coefficients determined by the influence function which was provided with kindness by M. Beghini from University of Pisa, Italy.

residual stress, hole drilling method, influence function, integral method, power series method

2006

15.05.2006

Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, Prague

Svratka, Czech Republic

80-86246-27-2

Engineering Mechanics 2006

13