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Study of crack growing through an interface of two different materials based on analysis of crack profile in the vicinity of crack tip
Bareš, Pavel
Paper describes a numerical study of a crack penetrating the interface between two different elastic materials. The stability conditions of a crack terminating at the interface are formulated. The method introduces herein for these purposes is based on the assumption that the crack will start to propagate through the interface into the second material M2 when the shape of the crack face in the immediate vicinity of the crack tip will correspond to that in the same sample but made of purely homogeneous material M2. The numerical calculations are performed on the sample with surface protective layer under the small scale yielding conditions. The resulting critical stresses are compared with those obtained by other approaches. All results are in qualitative agreement. This method should be applicable in cases of larger crack-tip plastic deformations as well, where so far known methods are not able. All numerical calculations are performed by finite element method (system ANSYS).
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Crack stability analysis of the crack in surface protective layers based on crack mouth opening displacement
Bareš, Pavel
Paper deals with stability analysis of a crack in a coating on a substrate. It is considered that the crack is perpendicularly oriented to the interface between the coating and the substrate and the crack tip lies directly on the material interface. The simple method based on crack mouth opening displacement parameter CMOD is proposed here for a critical stress calculation in the case of through coating crack in very thin coatings. The method is then applied herein on the model example and the critical stresses for different material combinations of the coating and the substrate are calculated. Note that under these stresses the crack will start propagate across the interface to the substrate. All calculations are performed by a finite element method FEM in the system ANSYS.
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Tři způsoby interpolace na konečných prvcích
Šolín, Pavel ; Segeth, Karel
Interpolation on finite elements usually occurs in a Hilbert space setting, which means that interpolation techniques involving orthogonal projection are an alternative for the traditional Lagrange nodal interpolation schemes. In addition to the Lagrange interpolation, this paper discusses the global orthogonal projection and the projection-based interpolation. These techniques are compared from the point of view of quality, efficiency, sensitivity to input parameters and other aspects.
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Programy a algoritmy numerické matematiky 12
This book contains more than 30 papers presented at the seminar Programs and Algorithms of Numerical Mathematics held in Dolní Maxov, Czech Republic, June 6-11, 2004. The contributions deal mostly with the finite element method and its applications. Other subjects, as spline construction, numerical linear algebra algorithms, or optimization, for example, are also covered.
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