Vliv rozdílné teplotní roztažnosti vláken a matrice na porušení kompozitů tvořených křehkou matricí.

Effect of thermal expansion mismatches of matrix and fibres on microcracking of brittle matrix composites

článek ve sborníku ve WoS nebo Scopus

en

There is investigated a crack problem for an array of collinear microcracks in composite matrix. Inclusions are situated in between the neighbouring microcracks tips and exhibit different elastic properties than matrix. The problem is solved using the technique of distributed dislocations. Stress intensity factor is calculated for various cracks/inclusions geometries and elastic moduli mismatches. The process by which a fibre-reinforced cross-ply ceramic composite is damaged and eventually fails under tension is very complex. After an initial elastic response, the damage starts with matrix cracking in 90 plies. These microcracks spread as 3D tunnelling cracks from small flaws located in the matrix of the 90 plies. Driving force for steady-state tunnelling, Gss, can be calculated using plane-strain elasticity solutions for the energy release rate G at the edge of plane-strain crack.

Je vyšetřován problém interakce kolineárních trhlin a inkluzí v křehké matrici. Problém je řešen pomocí techniky spojitě rozložených dislokací. Součinitel intenzity napětí je vypočten pro různá uspořádání mikrotrhlin a inkluzí a pro různé kombinace elastických konstant. Podrobně je zkoumán vliv teplotních napětí. Je diskutováno tunelování periodicky rozmístěných mikrotrhlin v lamelách kompositu orientovaných pod uhlem 90 vzhledem ke směru vnějšího tahového zatížení. Je stanovena velikost hnací síly Gss pro stacionární stav tunelujících mikrotrhlin.

There is investigated a crack problem for an array of collinear microcracks in composite matrix. Inclusions are situated in between the neighbouring microcracks tips and exhibit different elastic properties than matrix. The problem is solved using the technique of distributed dislocations. Stress intensity factor is calculated for various cracks/inclusions geometries and elastic moduli mismatches. The process by which a fibre-reinforced cross-ply ceramic composite is damaged and eventually fails under tension is very complex. After an initial elastic response, the damage starts with matrix cracking in 90 plies. These microcracks spread as 3D tunnelling cracks from small flaws located in the matrix of the 90 plies. Driving force for steady-state tunnelling, Gss, can be calculated using plane-strain elasticity solutions for the energy release rate G at the edge of plane-strain crack.

particle composites; continuously distributed dislocations; cracks-inclusions interactions, thermal expansion; crack tunnelling

2005

29.03.2005

ÚMTMB FSI v Brně

Brno

80-214-2373-0

Aplikovaná mechanika 2005

85–86

2