Measuring elastic–plastic properties of thin films on elastic–plastic substrates by sharp indentation

2009 ◽  
Vol 41 (3) ◽  
pp. 308-318 ◽  
Author(s):  
Yanguo Liao ◽  
Yichun Zhou ◽  
Yongli Huang ◽  
Limei Jiang
Keyword(s):  
Thin Films ◽  
Plastic Properties ◽  
Plastic Substrates ◽  
Elastic Plastic ◽  
Sharp Indentation

scholarly journals Analysis of the multi-cracking mechanism of brittle thin films on elastic-plastic substrates

2019 ◽  
Vol 180-181 ◽  
pp. 176-188 ◽  
Author(s):  
I. Ben Cheikh ◽  
G. Parry ◽  
D. Dalmas ◽  
R. Estevez ◽  
J. Marthelot
Keyword(s):  
Thin Films ◽  
Plastic Substrates ◽  
Elastic Plastic ◽  
Cracking Mechanism

EFFECTS OF PLASTIC ANISOTROPY AND HARDENING ON INDENTATION MODULUS OF THIN FILMS

2010 ◽  
Vol 24 (01n02) ◽  
pp. 247-255
Author(s):  
SALMON M. KALKHORAN ◽  
NUWONG CHOLLACOOP ◽  
ANDREW GOULDSTONE
Keyword(s):  
Thin Films ◽  
Plastic Anisotropy ◽  
Grain Structure ◽  
Plastic Behavior ◽  
Indentation Modulus ◽  
Plastic Substrates ◽  
Elastic Plastic ◽  
Nickel Thin Films ◽  
Columnar Grain ◽  
Steel Substrates

In this study we have modeled the Berkovich indentation response of elastic-plastic thin films on elastic-plastic substrates, the modulus of film and substrate being equivalent, using FEM. The stimulus for this investigation was experimental indentation data of rapidly quenched nickel thin films on stainless steel substrates, for which depth-dependent, significantly low (>50% decrease) moduli were extracted via the Oliver-Pharr method. This was notable because both film and substrate had the same elastic modulus. Previous studies showed that differences in plastic behavior could elicit such a modulus drop, for extremely hard films on substrates. In this study, we performed further FEM models to explore the modulus decrease, using aspects of continuum plastic behavior that could be hypothesized from microstructural observations. Specifically, we used plastic anisotropy and significant delayed hardening that would be expected from the nano-scale, highly columnar grain structure as input, and results showed a significant modulus decrease for reasonable values of hardness.

New sharp indentation method of measuring the elastic–plastic properties of compliant and soft materials using the substrate effect

2006 ◽  
Vol 21 (12) ◽  
pp. 3134-3151 ◽  
Author(s):  
Manhong Zhao ◽  
Xi Chen ◽  
Nagahisa Ogasawara ◽  
Anghel Constantin Razvan ◽  
Norimasa Chiba ◽  
...  
Keyword(s):  
Finite Thickness ◽  
Indentation Test ◽  
Soft Materials ◽  
Substrate Effect ◽  
Plastic Properties ◽  
Application Range ◽  
Elastic Plastic ◽  
Elastoplastic Properties ◽  
Uniqueness Of The Solution ◽  
Sharp Indentation

We propose a new theory with the potential for measuring the elastoplastic properties of compliant and soft materials using one sharp indentation test. The method makes use of the substrate effect, which is usually intended to be avoided during indentation tests. For indentation on a compliant and soft specimen of finite thickness bonded to a stiff and hard testing platform (or a compliant/soft thin film deposited on a stiff/hard substrate), the presence of the substrate significantly enhances the loading curvature which, theoretically, enables the determination of the material power-law elastic-plastic properties by using just one conical indentation test. Extensive finite element simulations are carried out to correlate the indentation characteristics with material properties. Based on these relationships, an effective reverse analysis algorithm is established to extract the material elastoplastic properties. By utilizing the substrate effect, the new technique has the potential to identify plastic materials with indistinguishable indentation behaviors in bulk forms. The error sensitivity and uniqueness of the solution are carefully investigated. Validity and application range of the proposed theory are discussed. In the limit where the substrate is taken to be rigid, the fundamental research is one of the first steps toward understanding the substrate effect during indentation on thin films deposited on deformable substrates.

scholarly journals Finite Pure Plane Strain Bending of Inhomogeneous Anisotropic Sheets

Symmetry ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 145
Author(s):  
Sergei Alexandrov ◽  
Elena Lyamina ◽  
Yeong-Maw Hwang
Keyword(s):  
Plane Strain ◽  
Yield Criterion ◽  
Large Strains ◽  
Rigid Plastic ◽  
Plastic Properties ◽  
Elastic Plastic ◽  
Starting Point ◽  
The Difference ◽  
Inside Radius ◽  
Elastic Unloading

The present paper concerns the general solution for finite plane strain pure bending of incompressible, orthotropic sheets. In contrast to available solutions, the new solution is valid for inhomogeneous distributions of plastic properties. The solution is semi-analytic. A numerical treatment is only necessary for solving transcendent equations and evaluating ordinary integrals. The solution’s starting point is a transformation between Eulerian and Lagrangian coordinates that is valid for a wide class of constitutive equations. The symmetric distribution relative to the center line of the sheet is separately treated where it is advantageous. It is shown that this type of symmetry simplifies the solution. Hill’s quadratic yield criterion is adopted. Both elastic/plastic and rigid/plastic solutions are derived. Elastic unloading is also considered, and it is shown that reverse plastic yielding occurs at a relatively large inside radius. An illustrative example uses real experimental data. The distribution of plastic properties is symmetric in this example. It is shown that the difference between the elastic/plastic and rigid/plastic solutions is negligible, except at the very beginning of the process. However, the rigid/plastic solution is much simpler and, therefore, can be recommended for practical use at large strains, including calculating the residual stresses.

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