Skip to Main content Skip to Navigation
Theses

Détermination des propriétés mécaniques de céramiques poreuses par essais de microindentation instrumentée sphérique

Abstract : The objective of this study is to develop a methodology to characterize the mechanical behaviour of porous inorganic materials. Spherical instrumented indentation tests were used to determine the mechanical properties of a model material, gypsum, with two different porosities (30 and 60% vol.). Classical analytical methods, initially developed for nano-indentation, were used to extract the hardness and the elastic modulus of both materials, as well as stress-strain indentation curves. A methodology has been detailed in order to apply spherical indentation test to study high porous ceramics. To complete this analytical analysis, a numerical approach is used to identify an elastoplastic constitutive law for the material model. A 2D axisymmetric finite element model was developed to simulate spherical indentation tests. An inverse identification module, MIC2M, was then used to identify parameters associated to Drücker-Prager criterion (cohesion, friction and dilatancy) by minimizing the error between the experimental and the simulated indentation curves. These parameters were validated through the numerical simulation of a Vickers indentation test. Uniaxial compression and oedometer tests were also carried out on cylindrical samples to estimate the accuracy of the identified parameters. The mechanisms occurring during indentation were investigated using RX tomography and SEM. A large densified zone was noted below the indented area, with extensive gypsum crystal fracture. No macroscopic brittle crack could be observed confirming the differences between the mechanical behaviour of high porous ceramics and dense ceramics. The methodology developed in this study was applied to calcium phosphate cements, widely used for bone substitution. In-vitro degradation tests were performed on cylindrical samples of cements during 2 months into a refreshed Phosphate Buffered Saline solution. The micro-indentation method was enabled to follow mechanical properties of degraded samples and was discriminant enough to monitor the degradation process and its kinetics. Results showed a good correlation between evolutions of mechanical and physico-chemical properties of the cement investigated by X-ray diffraction and SEM. Thus, after initial cement dissolution, precipitation of more stable phosphate calcium phases implied an increase of the mechanical properties during aging. This method seems to be a promising tool for monitoring biomedical explants properties and, more generally, high porous ceramics.
Document type :
Theses
Complete list of metadata

Cited literature [200 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00961208
Contributor : ABES STAR :  Contact
Submitted on : Wednesday, March 19, 2014 - 3:53:35 PM
Last modification on : Friday, September 30, 2022 - 11:40:09 AM
Long-term archiving on: : Thursday, June 19, 2014 - 12:21:14 PM

File

these.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-00961208, version 1

Citation

Phillipe Clément. Détermination des propriétés mécaniques de céramiques poreuses par essais de microindentation instrumentée sphérique. Autre. INSA de Lyon, 2013. Français. ⟨NNT : 2013ISAL0030⟩. ⟨tel-00961208⟩

Share

Metrics

Record views

1372

Files downloads

11480