ON THE CHALLENGING FEM ON THE CHALLENGING FEM APPLICATION FIELDS IN THE APPLICATION FIELDS IN THE FRACTURE MECHANICS FRACTURE MECHANICS Institute of Institute of Physics of Physics of Materials, AS of Materials, AS of CR, Brno, Czech CR, Brno, Czech Republic Republic Vladislav Kozák Vladislav Kozák
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ON THE CHALLENGING FEM APPLICATION FIELDS IN THE FRACTURE MECHANICS
ON THE CHALLENGING FEM APPLICATION FIELDS IN THE FRACTURE MECHANICS. Institute of Physics of Materials, AS of CR, Brno, Czech Republic. Vladislav Kozák. Outline. 1. Introduction 2. Local approach -Beremin 3. GTN model 4. Cohesive-zone modelling 5. Summary. 1.Introduction FTTD. - PowerPoint PPT Presentation
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ON THE CHALLENGING FEM ON THE CHALLENGING FEM APPLICATION FIELDS IN THE APPLICATION FIELDS IN THE
FRACTURE MECHANICSFRACTURE MECHANICS
Institute of Physics of Institute of Physics of Materials, AS of CR, Materials, AS of CR, Brno, Czech RepublicBrno, Czech Republic
Vladislav KozákVladislav Kozák
OutlineOutline
1. 1. Introduction Introduction
2. Local approach -Beremin2. Local approach -Beremin
Three different approaches to the Three different approaches to the damage modellingdamage modelling
no damage evaluation, elasto-plastic no damage evaluation, elasto-plastic constitutive equation, process zone is small, K, constitutive equation, process zone is small, K, J, C*J, C*
separation of surfaces is admitted, material separation of surfaces is admitted, material outside is described conventionally, the outside is described conventionally, the process zone is some surface region, fracture process zone is some surface region, fracture criterion is cohesive lawcriterion is cohesive law
softening behaviour is introduced into the softening behaviour is introduced into the constitutive model, e.g. accumulation of constitutive model, e.g. accumulation of damage, described by additional internal damage, described by additional internal variables, GTNvariables, GTN
Plastic zone ahead the crack Plastic zone ahead the crack tiptip
conditioncondition SSYSSY
conditionconditionelasto-plasticelasto-plastic
conditionconditionLSYLSY
regionregion::
large deformationlarge deformationJ-J-integralintegral conception conception K faktor K faktor conception conceptionnon defined only by non defined only by one parameterone parameter
2. 2. Local approach - BereminLocal approach - Beremin
· Beremin· Beremin model model 1. averaging stresses over 1. averaging stresses over
FPZFPZ 2. probability of fracture2. probability of fracture
· Extension to Fracture · Extension to Fracture MechanicsMechanics
1. direct toughness 1. direct toughness prediction for SSYprediction for SSY
The coincidence of the results of the numerical modelling and the The coincidence of the results of the numerical modelling and the experiment is generally the basic criterion.experiment is generally the basic criterion.