Vliv časově závislých materiálových na chování trhliny s vrcholem na materiálovém rozhraní

Effect of the time dependent material properties on the crack behaviour in the interface of two polymeric materials

článek v časopise - ostatní, Jost

en

Crack penetration through the bimaterial interface of two polymers is investigated umerically. Due to the practical importance of the problem, a crack in a three-layer pipe consisting of a main and two, inner and outer, protective layers is analyzed in this paper. The prime aim is to formulate the conditions under which the crack stays arrested at the interface between the protective layer and the main pipe or penetrates into the interface and causes failure of the main pipe and consequently of the entire pipe system. The crack tip stress field is described by using a generalized stress intensity factor for cases where the crack touches the interface and the stress singularity exponent differs from 1/2. In the case of short-term applications, the stress state on the interface is given simply by a combination of the elastic properties of materials of the main pipe and the protective layers. In long-term applications, the time-dependent properties of the materials can significantly influence the stress state of the interface and can lead to considerable changes in failure conditions. The results presented here may contribute to a more accurate estimation of the residual lifetime of multilayer pipes.

V této práci je studován vliv časově závislých materiálových vlastností na šíření trhliny z materiálového rozhraní u třívrstvé polymerní trubky. Cílem práce je stanovení podmínek kdy se trhlina nebude šířit nebo kdy dojde k šíření trhliny z rozhraní dvou materiálů.

Crack penetration through the bimaterial interface of two polymers is investigated umerically. Due to the practical importance of the problem, a crack in a three-layer pipe consisting of a main and two, inner and outer, protective layers is analyzed in this paper. The prime aim is to formulate the conditions under which the crack stays arrested at the interface between the protective layer and the main pipe or penetrates into the interface and causes failure of the main pipe and consequently of the entire pipe system. The crack tip stress field is described by using a generalized stress intensity factor for cases where the crack touches the interface and the stress singularity exponent differs from 1/2. In the case of short-term applications, the stress state on the interface is given simply by a combination of the elastic properties of materials of the main pipe and the protective layers. In long-term applications, the time-dependent properties of the materials can significantly influence the stress state of the interface and can lead to considerable changes in failure conditions. The results presented here may contribute to a more accurate estimation of the residual lifetime of multilayer pipes.

vícevrstvé polymerní trubky, bimateriálové rozhraní, kritérium stability, kritické napětí, časově závislé materiálové vlastnosti

multilayer plastic pipes, bimaterial interface, stability criteria, critical stress, time-depended material properties

2011

19.05.2011

0191-5665

MECHANICS OF COMPOSITE MATERIALS

47

2

203–210

8