Determination of an effective zero-point and extraction of indentation stress–strain curves without the continuous stiffness measurement signal

2009 ◽  
Vol 60 (6) ◽  
pp. 439-442 ◽  
Author(s):  
S PATHAK ◽  
J SHAFFER ◽  
S KALIDINDI
Keyword(s):  
Zero Point ◽  
Stress Strain ◽  
Stiffness Measurement ◽  
Measurement Signal ◽  
Continuous Stiffness Measurement

Determination of the effective zero point of contact for spherical nanoindentation

2008 ◽  
Vol 23 (1) ◽  
pp. 204-209 ◽  
Author(s):  
Alexander J. Moseson ◽  
Sandip Basu ◽  
Michel W. Barsoum
Keyword(s):  
Accurate Determination ◽  
Zero Point ◽  
Sample Surface ◽  
Fused Silica ◽  
Contact Radius ◽  
Stiffness Measurement ◽  
Continuous Stiffness Measurement ◽  
First Contact ◽  
Versus Strain

Accurate determination of the “zero point,” the first contact between an indenter tip and sample surface, has to date remained elusive. In this article, we outline a relatively simple, objective procedure by which an effective zero point can be determined accurately and reproducibly using a nanoindenter equipped with a continuous stiffness measurement option and a spherical tip. The method relies on applying a data shift, which ensures that curves of stiffness versus contact radius are linear and go through the origin. The method was applied to fused silica, sapphire single crystals, and polycrystalline iron with various indenter sizes to a zero-point resolution of ≈2 nm. Errors of even a few nanometers can drastically alter plots and calculations that use the data, including curves of stress versus strain.

scholarly journals Relationship of Stiffness-Based Indentation Properties Using Continuous-Stiffness-Measurement Method

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 97 ◽  
Author(s):  
Wai Yeong Huen ◽  
Hyuk Lee ◽  
Vanissorn Vimonsatit ◽  
Priyan Mendis
Keyword(s):  
Elastic Modulus ◽  
Measurement Method ◽  
Computational Simulation ◽  
Accurate Solution ◽  
New Approach ◽  
Stiffness Measurement ◽  
Pile Up ◽  
Continuous Stiffness Measurement ◽  
Relationship Of

The determination of elastic modulus (E) and hardness (H) relies on the accuracy of the contact area under the indenter tip, but this parameter cannot be explicitly measured during the nanoindentation process. This work presents a new approach that can derive the elastic modulus (E) and contact depth (hc) based on measured experiment stiffness using the continuous-stiffness-measurement (CSM) method. To achieve this, an inverse algorithm is proposed by incorporating a set of stiffness-based relationship functions that are derived from combining the dimensional analysis approach and computational simulation. This proposed solution considers both the sink-in and pile-up contact profiles; therefore, it provides a more accurate solution when compared to a conventional method that only considers the sink-in contact profile. While the proposed solution is sensitive to Poisson’s ratio (ν) and the equivalent indentation conical angle (θ), it is not affected by material plasticity, including yield strength (σy) and work hardening (n) for the investigated range of 0.001 < σy/E < 0.5. The proposed stiffness-based approach can be used to consistently derive elastic modulus and hardness by using stiffness and the load-and-unload curve measured by the continuous-stiffness-measurement (CSM) method.

scholarly journals Determination of stress-strain state of the wooden church log walls with software package

2016 ◽  
Vol 86 ◽  
pp. 02019 ◽  
Author(s):  
Anastasia Chulkova ◽  
Sergey Lukichev ◽  
Marina Romanovich
Keyword(s):  
Software Package ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State

Determination of the stress-strain state of anisotropic thermosensitive cylinders

1999 ◽  
Vol 97 (1) ◽  
pp. 3826-3829
Author(s):  
Ya. M. Grigorenko ◽  
A. T. Vasilenko
Keyword(s):  
Strain State ◽  
Stress Strain ◽  
Stress Strain State
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