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E u r o S c i C o n C o n f e r e n c e o n
Nanotechnology &
Smart Materials
Nano Research & Applications
ISSN 2471-9838
O c t o b e r 0 4 - 0 6 , 2 0 1 8
Am s t e r d a m , N e t h e r l a n d s
Nanotechnology & Smart Materials 2018
Page 75
Ceramic materials often involve complex constitutive models apt to describe
material mechanical behaviour required for accurate numerical simulations.
These models can use either micro-mechanical approaches to address crystalline
scale or phenomenological approaches by studying the response of representative
volume of material. When proper model is selected, the accuracy of simulations
rests on quantification of parameters (i.e. material properties) entering into
governing equations. The assessment of these properties is done on the basis
of experiments. For complex models governed by large number of parameters,
such calibration is rather challenging. If the selected experiment be too simple, the
parameter quantification results in fitting the response of single experiment, not in
the assessment or material representative properties. Systematic way of resolving
this difficulty is through the application of inverse analysis, centered on the
minimization of discrepancy function designed to quantify the difference between
measured quantities and their computed counter parts. Designed discrepancy
function thus depends on elevated number of sought parameters, so the inverse
problem is typically ill-posed requiring the application of various regularization
techniques, with measured quantities carefully selected to ascertain good
sensitivity to the parameters. Within this lecture, some methodological novelties
related to the above outlined problem will be presented with reference to two
engineering problems. The first one concerns the calibration of phenomenological
models used to simulate ceramic powder compaction. It will be shown that through
inverse analysis identification of parameters can be performed using only data
collected from compaction test. The second problem concerns thermally induced
micro-cracking observed in porous ceramics employed for diesel particulate
filters. A micro mechanical model is developed and numerically implemented to
simulate crack initiation and healing, typically observed within these materials
when subjected to thermal cycling. By incorporating the developed model with
inverse analysis inter-granular fracture toughness of considered ceramic material
can be assessed
Biography
Vladimir Buljak has completed his PhD in 2009 from Politecni-
co di Milano. Upon completion of his PhD, he spent additional
two years as Postdoc within the same institution up to 2011.
After that, he moved to the University of Belgrade, Mechanical
Engineering Faculty, as an Assistant Professor at the Depart-
ment of Strength of materials from 2016. He became an As-
sociate Professor at the same institution. He is Professor In
Charge as Visiting Professor for the course Theory of plasticity
at Politecnico di Milano since 2015. He was Visiting Scientist
at University of Trento in 2014 and German Federal institute
for materials research and testing - BAM at Berlin in 2016. He
was Scientist In Charge for University of Belgrade for European
FP7-INT project CERMAT2, dealing with advanced ceramic ma-
terials. He has published one book and more than 20 papers in
reputed journals.
Assessment of representative material
properties of ceramic materials through
inverse analysis
Vladimir Buljak
University of Belgrade, Serbia
Vladimir Buljak, Nano Res Appl Volume:4
DOI: 10.21767/2471-9838-C6-024