Quantification of the pile-up effect for improving inverse mechanical analysis by means of nanoindentation

This paper deals with the identification of elastic-plastic material properties by means of nanoindentation. A dimensional analysis leads to the identification of a specific parameter based on the estimation of the pile-up effect. This parameter may be used in an inverse analysis. Theoretical aspects and experimental issues are discussed

Parametric identification of elastic-plastic constitutive laws using spherical indentation

In this paper we present a methodology to characterize elastic-plastic constitutive law of metallic materials using spherical indentation tests and parametric identification coupled with finite elements model simulation. This procedure was applied to identify aluminium, copper and titanium mechanical properties and the identified models show difference that do not exceed 10% with experimental uniaxial tensile tests results. A sensitivity study according to a 2^k Design of Experience (DoE) was achieved to determine which data that can be extracted from pile-up is the most relevant to use in order to enhance the identification procedure. It appears that the maximum pile-up height seems to be the best suited for this purpose

Validation of mechanical damage monitoring on aluminium freestanding thin films using electrical measurements

This paper describes a new technique allowing the monitoring of damage in metallic freestanding thin films during micro-tensile test by using electrical characterization. After a presentation of the set-up, results obtained on aluminium thin coatings by using two calculation methods for damage variable are presented and commented

A comparative study of microscratch and microtensile adhesion tests for nickel coatings on various substrates

The present paper first focuses on discussing application ranges for the scratch test and the microtensile test. For that purpose, both have been implemented on the same nickel coating plated on several substrates, in particular a PCB, which are expected to have different adhesion behaviors. Afterward, correlations are highlighted between these two types of adhesion tests

Micro Tensile Tests on Aluminium Thin Films: Tensile Device and In Situ Observations

International audienc

Micro Tensile Tests on Aluminium Thin Films: Tensile Device and In Situ Observations

International audienc

Nanoindentation experiments with small tip radii: an experimental method

International audienc

Methodology to Analyze Failure Mechanisms of Ohmic Contacts on MEMS Switches

International audienceThis paper demonstrates the efficiency of a new methodology using a commercial nanoindenter coupling with electrical measurement on test vehicles specially designed to investigate the micro contact reliability. This study examines the response of gold contacts with 5 μm² square bumps under various levels of current flowing through contact asperities. Contact temperature rising is observed leading to shifts of the mechanical properties of contact material, modifications of the contact topology and a diminution of the time dependence creep effect. The data provides a better understanding of micro-scale contact physics especially failure mechanisms due to the heating of the contact on MEMS switches

Two channel EUV mirror for solar missions: design, performances and stability

PosterInternational audienc