scholarly journals Numerical Simulation of the Depth-Sensing Indentation Test with Knoop Indenter

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 885 ◽  
Author(s):  
Maria Simões ◽  
Jorge Antunes ◽  
José Fernandes ◽  
Nataliya Sakharova
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Indentation Test ◽  
Depth Sensing ◽  
Element Mesh ◽  
Reliable Determination ◽  
Numerical Studies ◽  
Knoop Indentation ◽  
Knoop Indenter

Depth-sensing indentation (DSI) technique allows easy and reliable determination of two mechanical properties of materials: hardness and Young’s modulus. Most of the studies are focusing on the Vickers, Berkovich, and conical indenter geometries. In case of Knoop indenter, the existing experimental and numerical studies are scarce. The goal of the current study is to contribute for the understanding of the mechanical phenomena that occur in the material under Knoop indention, enhancing and facilitating the analysis of its results obtained in DSI tests. For this purpose, a finite element code, DD3IMP, was used to numerically simulate the Knoop indentation test. A finite element mesh was developed and optimized in order to attain accurate values of the mechanical properties. Also, a careful modeling of the Knoop indenter was performed to take into account the geometry and size of the imperfection (offset) of the indenter tip, as in real cases.

Methods of correction for analysis of depth-sensing indentation test data for spherical indenters

2001 ◽  
Vol 16 (8) ◽  
pp. 2244-2250 ◽  
Author(s):  
A. C. Fischer-Cripps ◽  
A. Bendeli ◽  
T. J. Bell ◽  
J. S. Field ◽  
A. K. Jamting
Keyword(s):  
Mechanical Properties ◽  
Indentation Test ◽  
Depth Sensing ◽  
Test Parameters ◽  
Initial Penetration ◽  
Recorded Data ◽  
Potential Methods ◽  
Indenter Shape ◽  
Data Analysis Methods

Depth-sensing indentation testing has proven extremely useful in the determination of mechanical properties of thin films and small volumes of material. However, the validity of the results obtained depend largely on the corrections made to the experimentally recorded data to account for initial penetration depth, nonuniformities in indenter shape, and compliance of the loading frame. The present work examines each of these issues and presents potential methods of correction for them. The present work also highlights limitations inherent in the data analysis methods and the significance of these in terms of experimental test parameters.

EFFECT OF MECHANICAL PROPERTIES OF THE SUBSTRATE TISSUES ON THE DETERMINATION OF ELASTIC MODULUS OF THE SCLERA USING INDENTATION TEST

2016 ◽  
Vol 16 (07) ◽  
pp. 1650085
Author(s):  
XIUQING QIAN ◽  
KUNYA ZHANG ◽  
ZHICHENG LIU
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Elastic Moduli ◽  
Indentation Depth ◽  
Vitreous Body ◽  
Indentation Test ◽  
Posterior Pole

The sclera is an important connective tissue that protects the sensitive layers within the eyeball. Identifying the mechanical properties of the sclera near the posterior pole is necessary to analyze the deformation of the sclera and stresses changing in the optic nerve head tissues. We propose a method to determine the mechanical properties of the sclera using dimensional analysis, finite element method and the indentation test. The elastic moduli of the sclera for different indentation depths and positions were identified. We found that the elastic moduli of the sclera varied with indentation depth. This was due to the effect of the mechanical properties of the substrate tissues inside the sclera. The elastic modulus of the choroid had the biggest effect on the determination of elastic modulus of the sclera, whereas that of the vitreous body could be ignored when the ratio of the indentation depth to the thickness of the sclera was less than 0.5. The effects of mechanical properties of the substrate tissues become more pronounced at greater indentation depths.

scholarly journals Analysis of depth-sensing indentation tests with a Knoop indenter

2001 ◽  
Vol 16 (6) ◽  
pp. 1660-1667 ◽  
Author(s):  
L. Riester ◽  
T. J. Bell ◽  
A. C. Fischer-Cripps
Keyword(s):  
Elastic Modulus ◽  
Elastic Recovery ◽  
Indentation Test ◽  
New Method ◽  
Short Axis ◽  
Depth Sensing ◽  
Specimen Material ◽  
Indentation Tests ◽  
Conventional Methods ◽  
Knoop Indenter

The present work shows how data obtained in a depth-sensing indentation test using a Knoop indenter may be analyzed to provide elastic modulus and hardness of the specimen material. The method takes into account the elastic recovery along the direction of the short axis of the residual impression as the indenter is removed. If elastic recovery is not accounted for, the elastic modulus and hardness are overestimated by an amount that depends on the ratio of E/H of the specimen material. The new method of analysis expresses the elastic recovery of the short diagonal of the residual impression into an equivalent face angle for one side of the Knoop indenter. Conventional methods of analysis using this corrected angle provide results for modulus and hardness that are consistent with those obtained with other types of indenters.

scholarly journals The creation of a computational model of corrugated beams using the author’s program “GOPRO”

2018 ◽  
Vol 251 ◽  
pp. 04007 ◽  
Author(s):  
Vadim Alpatov ◽  
Alexey Lukin ◽  
Irina Laguta
Keyword(s):  
Finite Element ◽  
Computational Model ◽  
Cross Section ◽  
Geometrical Shape ◽  
File Format ◽  
Element Mesh ◽  
Automated Generation ◽  
Numerical Studies ◽  
Geometrical Scheme ◽  
The Web

The program «Gofro» is intended for the automated generation of data on the geometrical scheme of the beam with corrugated or plane web for further use in design complexes. The program has got a window interface, and it consists of one module for the input of feed da-ta, for calculation and for the display of its results in txt file format. The program offers a possibility to choose the outline of the structure, the profile of the web, the type of cross-section, and to set other parameters of the structure. When building up the model with the help of the author program «Gofro» and GMSH preprocessor for the automatic genera-tion of finite element mesh, the correctness of geometrical shape of elements is monitored by the algorithms that are input in the preprocessor. The author compares the time re-quired to create the models using the author program and GMSH preprocessor and using the standard resources of «Lira» software system. The authors performed numerical studies of various I-beams created in the program «GOPRO».

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