Microindentation Test Modelling in the Silicon Nitride Ceramics

0435046 - ÚFM 2015 RIV DE eng O - Others
Kozák, Vladislav - Chlup, Zdeněk
Microindentation Test Modelling in the Silicon Nitride Ceramics.
2014
EU Projects: European Commission(XE) 263476 - ROLICER
Institutional support: RVO:68081723
Keywords : Silicon nitride * Cohesive zone model * FEM
Subject RIV: JL - Materials Fatigue, Friction Mechanics

Silicon nitride based ceramics have received considerable attention during the last decades due to their very good room and high-temperature properties. Such ceramics are acknowledged as first choice for application of modern hybrid bearing applications. The influence of crack bridging by the elongated grains present in the microstructure on the strength and toughness is well known phenomenon from the side of experimental observation. The modelling of this complex microstructure by classical continuum mechanic approach usually do not provide sufficient results. The prediction of the crack propagation through interface elements based on the fracture mechanics approach and cohesive zone model was investigated. The cohesive models seem to be especially attractive for practical applications in case of silicon nitride based ceramics. The behaviour of such materials was studied by two types of elements using cohesive models. The former is the element for the classical continuum and the latter is the connecting cohesive element. The new element type within the standard finite element package Abaqus has been developed and was written via the UEL procedure. The shape of the traction separation law for experimental materials was estimated from the macroscopic mechanical tests, J–R curve was predicted and stability of the bridging law was tested within this work. The shape of the bridging law was verified using the micro-indentation test, where the maximum crack length not exceeded 200e-6 m. The scope of the bridging effect was verified using the standard XFEM implemented in Abaqus and will be demonstrated within this contribution.
Permanent Link: http://hdl.handle.net/11104/0239592