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91.
92.
Claudio Scavia 《Meccanica》1991,26(1):27-32
The application of the displacement discontinuity numerical technique to the solution of some problems of fracture mechanics is demonstrated in the hypothesis of homogeneous and elastic material. The fracture is supposed to be free from traction and is represented by a set of constant displacement discontinuity elements, except for two parabolic elements, located at each crack tip, in order to simulate the singularity of the solution near the crack tips. On the basis of the stress and displacement field determined by the displacement discontinuity method, the stress intensity factors for mode I and II are computed according to the method of the displacements. Three examples are provided to verify the validity of the formulation.
Sommario Lo scopo del presente lavore è di illustrare l'applicazione del metodo numerico della Displacement Discontinuity alla soluzione di alcuni problemi di meccanica della frattura, nell'ipotesi di materiale omogeneo ed elastico. La frattura è supposta aperta ed è rappresentata da una linea di elementi a discontinuità di spostamento costante, con l'eccezione di due speciali elementi parabolici, ubicati agli apici, al fine di simulare la singolarita' del campo tensionale. Sulla base del campo degli sforzi e degli spostamenti cosi determinati, vengono ricavati i fattori di concentrazione degli sforzi in modo I e II mediante il metodo degli spostamenti. Vengono inoltre riportati tre esempi di calcolo, effettuati al fine di verificare la validità del procedimento proposto.相似文献
93.
A system of boundary integral equations that allows evaluating the displacement and stress fields for an interfacial crack
under harmonic loading is presented. Expressions for the integral kernels are obtained. A numerical solution for a penny-shaped
crack between steel and aluminum half-spaces under normally incident compression-rarefaction wave is given
__________
Translated from Prikladnaya Mekhanika, Vol. 43, No. 8, pp. 47–56, July 2007. 相似文献
94.
Brahim El Khalil Hachi Said Rechak Mohamed Haboussi Mbarek Taghite 《Comptes Rendus Mecanique》2006,334(1):83-90
A method improving the evaluation of the stress intensity factor by hybridization of two weight functions is presented and applied to embedded elliptical cracks under various loadings. The hybridization consists in using one or the other function in the zone of the crack where it is the most efficient. The delimitation of the two zones is achieved after optimizing the axes ratio and the curvature radius of the crack. During this optimization we seek to reduce the effects of the singularities present in the weight functions as well as to take better into account the influence of the ellipse curvature. To cite this article: B. El Khalil Hachi et al., C. R. Mecanique 334 (2006). 相似文献
95.
Stress intensity factors and crack deviation conditions in a brittle anisotropic solid 总被引:1,自引:0,他引:1
S. A. Nazarov 《Journal of Applied Mechanics and Technical Physics》2005,46(3):386-394
For arbitrary anisotropy in the linear manifold of singular solutions generating square-root singularities of the crack tip
stress, a special basis is introduced that possesses the same properties as in the isotropic case and provides simple integral
representations for the attributes of the energy fracture criterion, in particular, the conditions of crack deviation from
a straight path.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 3, pp. 98–107, May–June, 2005. 相似文献
96.
97.
疲劳裂纹扩展门槛值的研究进展 总被引:6,自引:0,他引:6
Ⅰ.引言 大量的研究和疲劳裂纹扩展的试验表明,对于存在一定尺寸裂纹及缺陷的材料或构件,只有当裂纹尖端的应力强度因子达到或超过某一值时,裂纹才会在交变应力的作用下扩展。当裂纹尖端的应力强度因子小于这一值时,裂纹在交变应力作用下不发生扩展。这个应力强度因子值,就是界限应力强度因予幅值△K_(th),在疲劳研究中称为裂纹扩展的门槛值。 门槛值△K_(th)和疲劳裂纹扩展速率da/dN一样,是反映带裂纹或缺陷构件抗疲劳性能的 相似文献
98.
A general method based on complex variable theory is proposed to determine the magnetic and elastic fields of a piezomagnetic
body. This method is used to derive the basic relations for complex potentials in the two-dimensional problem of magnetoelasticity,
their general representations for a multiply connected domain, expressions for stresses, displacements, vectors of magnetic
field intensity and magnetic flux density, and magnetic field potential. A closed-form solution is obtained for a body with
an elliptic (circular) hole or crack subjected at infinity to the action of a constant magnetoelastic field. Numerical results
for a piezomagnetic plate with a circular hole are presented
__________
Translated from Prikladnaya Mekhanika, Vol. 41, No. 10, pp. 64–74, October 2005. 相似文献
99.
Considered is a Yoffe crack in an infinite strip of functionally grated material (FGM) subjected to antiplane shear. The shear moduli in two directions of FGM are assumed to be of exponential form. The dynamic stress intensity factor and strain energy density factor at the crack tip are obtained by using integral transforms and dual-integral equations. The numerical results show that the decrease of the strain energy density factor varies with the shear moduli gradient, and the increase of the strain energy density factor varies with the increase of the moving crack speed. The ratio of shear moduli in material vertical orientation has a great influence on the strain energy density factor. 相似文献
100.