Evaluation of tensile strength of Al7075-SiC nanocomposite compacted by gas gun using spherical indentation test and neural networks

2016 ◽  
Vol 27 (4) ◽  
pp. 1821-1827 ◽  
Author(s):  
A. Atrian ◽  
G.H. Majzoobi ◽  
S.H. Nourbakhsh ◽  
S.A. Galehdari ◽  
R. Masoudi Nejad
Keyword(s):  
Neural Networks ◽  
Tensile Strength ◽  
Indentation Test ◽  
Spherical Indentation ◽  
Gas Gun

Modeling tensile strength and suture retention of polycaprolactone electrospun nanofibrous scaffolds by artificial neural networks

2021 ◽  
Vol 26 ◽  
pp. 102115
Author(s):  
B.S. Reddy ◽  
Kim Hong In ◽  
Bharat B. Panigrahi ◽  
Uma Maheswera Reddy Paturi ◽  
K.K. Cho ◽  
...  
Keyword(s):  
Neural Networks ◽  
Tensile Strength ◽  
Artificial Neural Networks ◽  
Nanofibrous Scaffolds ◽  
Artificial Neural

Can indentation technique measure unique elastoplastic properties?

2009 ◽  
Vol 24 (3) ◽  
pp. 784-800 ◽  
Author(s):  
Ling Liu ◽  
Nagahisa Ogasawara ◽  
Norimasa Chiba ◽  
Xi Chen
Keyword(s):  
Critical Strain ◽  
Indentation Test ◽  
Strain Curve ◽  
Spherical Indentation ◽  
Plastic Behavior ◽  
Displacement Curve ◽  
Application Range ◽  
Indentation Technique ◽  
Elastoplastic Properties ◽  
Force Displacement

Indentation is widely used to extract material elastoplastic properties from measured force-displacement curves. Many previous studies argued or implied that such a measurement is unique and the whole material stress-strain curve can be measured. Here we show that first, for a given indenter geometry, the indentation test cannot effectively probe material plastic behavior beyond a critical strain, and thus the solution of the reverse analysis of the indentation force-displacement curve is nonunique beyond such a critical strain. Secondly, even within the critical strain, pairs of mystical materials can exist that have essentially identical indentation responses (with differences below the resolution of published indentation techniques) even when the indenter angle is varied over a large range. Thus, fundamental elastoplastic behaviors, such as the yield stress and work hardening properties (functions), cannot be uniquely determined from the force-displacement curves of indentation analyses (including both plural sharp indentation and deep spherical indentation). Explicit algorithms of deriving the mystical materials are established, and we qualitatively correlate the sharp and spherical indentation analyses through the use of critical strain. The theoretical study in this paper addresses important questions of the application range, limitations, and uniqueness of the indentation test, as well as providing useful guidelines to properly use the indentation technique to measure material constitutive properties.

Identification of Hardening Parameters of Metals From Spherical Indentation Tests

2001 ◽  
Vol 123 (3) ◽  
pp. 245-250 ◽  
Author(s):  
S. Kucharski ◽  
Z. Mro´z
Keyword(s):  
Indentation Test ◽  
Strain Curve ◽  
Load Level ◽  
Spherical Indentation ◽  
Indentation Tests ◽  
Geometric Sequence ◽  
Loading And Unloading ◽  
Plastic Hardening ◽  
Hardening Curve ◽  
Two Parameters

The identification method of hardening parameters specifying stress-strain curve is proposed by applying spherical indentation test and measuring the penetration depth during loading and unloading. The loading program is composed of a geometric sequence of loading and partial unloading steps from which the variation of permanent penetration with load level is determined. This data is used for specification of two parameters k and m occurring in the plastic hardening curve εp=σ/k1/m, where εp denotes the plastic strain.

Advances in measuring mechanical properties of soil in relation to soil health

2021 ◽  
pp. 215-240
Author(s):  
Muhammad Naveed ◽  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Soil Health ◽  
Indentation Test ◽  
Mechanical Tests ◽  
Confined Compression ◽  
Microstructural Stability ◽  
Rigorous Testing ◽  
The Stability ◽  
Properties Of Soil

Although mechanical properties of soil are fast and easy to measure, they have not been used as indicators of soil health apart from cone penetration resistance. The confined compression test is traditionally used for the prediction of soil compaction risks. Other mechanical tests such as soil rheometry, miniature indentation test, and tensile strength are used for assessing the impact of certain amendments on the stability of the soil. Rheological techniques are appropriate to investigate microstructural stability of soil on a particle-particle scale. Miniature indentation test is very useful to perform when mechanical properties of soil are required to measure at the mm scale. Measurement of the tensile strength of soil has an advantage as it eliminates the effect of water content. There is clearly a need for more practical and rigorous testing on comparing different mechanical properties of the soil to test how they perform relative to each other.

Determining engineering stress–strain curve directly from the load–depth curve of spherical indentation test

2010 ◽  
Vol 25 (12) ◽  
pp. 2297-2307 ◽  
Author(s):  
Baoxing Xu ◽  
Xi Chen
Keyword(s):  
Indentation Test ◽  
Strain Curve ◽  
Spherical Indentation ◽  
Displacement Curve ◽  
Large Set ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Constraint Factors ◽  
Engineering Stress ◽  
Depth Curve

The engineering stress–strain curve is one of the most convenient characterizations of the constitutive behavior of materials that can be obtained directly from uniaxial experiments. We propose that the engineering stress–strain curve may also be directly converted from the load–depth curve of a deep spherical indentation test via new phenomenological formulations of the effective indentation strain and stress. From extensive forward analyses, explicit relationships are established between the indentation constraint factors and material elastoplastic parameters, and verified numerically by a large set of engineering materials as well as experimentally by parallel laboratory tests and data available in the literature. An iterative reverse analysis procedure is proposed such that the uniaxial engineering stress–strain curve of an unknown material (assuming that its elastic modulus is obtained in advance via a separate shallow spherical indentation test or other established methods) can be deduced phenomenologically and approximately from the load–displacement curve of a deep spherical indentation test.

Poroelastic Indentation Analysis for Hydrated Biological Tissues

2006 ◽  
Vol 975 ◽  
Author(s):  
Michelle L. Oyen ◽  
Amanpreet K. Bembey ◽  
Andrew J. Bushby
Keyword(s):  
Indentation Test ◽  
Biological Tissues ◽  
Time Dependent ◽  
Spherical Indentation ◽  
Indentation Creep ◽  
Polar Solvents ◽  
Viscoelastic Analysis ◽  
Wide Range ◽  
Indentation Problem

ABSTRACTIndentation techniques are employed for the measurement of mechanical properties of a wide range of materials. In particular, techniques focused at small length-scales, such as nanoindentation and AFM indentation, allow for local characterization of material properties in heterogeneous materials including natural tissues and biomimetic materials. Typical elastic analysis for spherical indentation is applicable in the absence of time-dependent deformation, but is inappropriate for materials with time-dependent responses. Recent analyses for the viscoelastic indentation problem, based on elastic-viscoelastic correspondence, have begun to address the issue of time-dependent deformation during an indentation test. The viscoelastic analysis has been shown to fit experimental indentation data well, and has been demonstrated as useful for characterization of viscoelasticity in polymeric materials and in hydrated mineralized tissues. However, a viscoelastic analysis is not necessarily sufficient for multi-phase materials with fluid flow. In the current work, a poroelastic analysis—based on fluid motion through a porous elastic network—is used to examine spherical indentation creep responses of hydrated biological materials. Both analytical and finite element approaches are considered for the poroelastic Hertzian indentation problem. Modeling results are compared with experimental data from nanoindentation of hydrated bone immersed in water and polar solvents (ethanol, methanol, acetone). Baseline (water-immersed) bone responses are characterized using the poroelastic model and numerical results are compared with altered hydration states due to polar solvents.

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