Posouzení šíření trhliny přes rozhraní dvou různých materiálů na základě analýzy profilu trhliny v blízkosti jejího kořene

Study of crack growing through an interface between two different materials based on analysis of crack profile in the vicinity of crack tip

conference paper

Czech

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 (under the critical stress). 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. The first of them is based on the comparison of average normal stress value in front of the crack tip with the characteristic critical value and the second is based on the comparison of the crack tip plastic zone sizes in the bimaterial and in the homogenous material. All results are in qualitative agreement and then herein reported method seems to be another useful method for critical stresses determination in bimaterial systems. 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).

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 (under the critical stress). 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. The first of them is based on the comparison of average normal stress value in front of the crack tip with the characteristic critical value and the second is based on the comparison of the crack tip plastic zone sizes in the bimaterial and in the homogenous material. All results are in qualitative agreement and then herein reported method seems to be another useful method for critical stresses determination in bimaterial systems. 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).

fracture machanics, bimaterial, crack stability, crack opening

BAREŠ, P.

2005

29. 3. 2005

Ústav machaniky těles, mechatroniky a biomechaniky, Fakulta strojního inženýrství, Vysoké učení technické v Brně

Hrotovice

80-214-2373-0

Aplikovaná Mechanika 2005

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