Comment on the determination of mechanical properties from the energy dissipated during indentation

2005 ◽  
Vol 20 (5) ◽  
pp. 1090-1092 ◽  
Author(s):  
Jürgen Malzbender
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Total Energy ◽  
Energy Dissipated

Based on a comparison of relationships between the energy dissipated during indentation and the ratio of hardness to elastic modulus, a procedure is outlined to determine hardness and elastic modulus from the ratio of the elastic to total energy dissipated during an indentation cycle for non-ideal indenters.

Comments on “Comment on the determination of mechanical properties from the energy dissipated during indentation” by J. Malzbender [J. Mater. Res. 20, 1090 (2005)]

2006 ◽  
Vol 21 (1) ◽  
pp. 302-305 ◽  
Author(s):  
J. Alkorta ◽  
J.M. Martínez–Esnaola ◽  
J. Gil Sevillano ◽  
Jürgen Malzbender
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Penetration Curve ◽  
Accurate Analysis ◽  
Indentation Curve ◽  
Energy Dissipated

Based on a comparison of relationships between energy dissipated during indentation and the ratio of hardness to reduced elastic modulus, Malzbender has recently proposed a procedure to determine both hardness and elastic modulus from a single loading–unloading indentation curve. However, a more accurate analysis of this relationship shows that, in fact, it suffers from the same limitations as the well-known Oliver and Pharr's method; i.e., in general, the true projected imprint area has to be measured in addition to the load–penetration curve or at least two such curves obtained with different indenter geometries are to be used to unequivocally determine the hardness and the elastic modulus of a material.

Characterization of the Mechanical Properties of Spring Materials

1974 ◽  
Vol 96 (3) ◽  
pp. 839-844 ◽  
Author(s):  
G. F. Weissmann ◽  
B. C. Wonsiewicz
Keyword(s):  
Mechanical Properties ◽  
Quality Control ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Energy Dissipation ◽  
Yield Strength ◽  
Tensile Testing ◽  
Control Applications

Spring materials are purchased under specifications which impose limits on the tensile strength but do not control the crucial properties, i.e., resistance to plastic flow and stiffness. Present techniques for characterizing spring material are discussed in detail. A novel test is described which is quick, inexpensive, and reliable and holds promise for both research and quality control applications. The test is based on a dynamic determination of energy dissipation in a sample stressed in bending or torsion, the usual modes of deformation for most springs. Stiffness and permissible deformations are determined directly and the elastic modulus and yield strength can be calculated easily. The results obtained in this way compare favorably with those determined by tensile testing. An example is given which illustrates the operation of the test and the calculation of results. Since the entire test from sample preparation to calculation of results requires about five minutes, and since the apparatus should be relatively inexpensive, the test ought to find application in many areas where testing is not practical at the present time.

scholarly journals Determination of Thermo-Mechanical Properties of Recycled Polyurethane From Glycolysis Polyol

2021 ◽  
Vol 11 (4) ◽  
pp. 75-87
Author(s):  
James Njuguna ◽  
Peter Muchiri ◽  
Nancy Karuri ◽  
Fredrick Madaraka Mwema ◽  
Michael T. Herzog ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Glass Transition ◽  
Elastic Modulus ◽  
Transition Temperature ◽  
Hardness Test ◽  
Raw Material ◽  
Glass Transition Temperatures ◽  
D Values

This study aimed to determine the possible changes in thermo-mechanical properties between recycled polyurethane with benchmark polyurethane. The glycolysis polyol was used as a raw material for recycled polyurethane production. The glass transition temperature of the recycled polyurethane was determined using DSC. Tensile strength, elastic modulus, toughness, and hardness test of the recycled polyurethane were conducted at 24°C, 40°C, and 60°C. The glass transition temperatures for the recycled and the benchmark polyurethane occurred at 43°C and 50.4°C, respectively. Tensile strength for recycled polyurethane was lower than that of benchmark polyurethane by 29-43%. Recycled polyurethane recorded lower toughness than petroleum-based pure polyurethane by 13-16%. However, recycled polyurethane recorded high shored D values than the benchmark polyurethane by 9-29%. This study reveals that recycled polyol could be used as feedstock for polyurethane production with applications tailored to its mechanical properties.

Errors associated with depth-sensing microindentation tests

1995 ◽  
Vol 10 (6) ◽  
pp. 1491-1501 ◽  
Author(s):  
J. Menčík ◽  
M.V. Swain
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Thermal Drift ◽  
Measuring Instrument ◽  
Material Characteristic ◽  
Depth Sensing ◽  
Characteristic Features ◽  
Indenter Geometry

In the determination of mechanical properties by ultra-microindentation, various errors can appear. This paper analyzes various sources of errors in estimation of elastic modulus and hardness. These errors arise from uncertainties of the indenter geometry and properties, as well as measuring instrument limitations and errors, such as the minimum detectable load, compliance, and noise of the system. Other sources of errors are thermal drift, shape of the impression, and scatter of properties of the tested material. Characteristic features and the magnitude of individual kinds of errors are discussed, together with formulas and recommended methods for their reduction.

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.

Determination of the Elastic Modulus of Hydroxyapatite Doped with Magnezium through Nondestructive Testing

2013 ◽  
Vol 814 ◽  
pp. 115-122 ◽  
Author(s):  
Oana Suciu ◽  
Liviu Bereteu ◽  
Gheorghe Drăgănescu ◽  
Teodora Ioanovici
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Chemical Element ◽  
Elasticity Modulus ◽  
Implant Surface ◽  
Vibration Signals ◽  
Normal Bone ◽  
Determination Methods ◽  
Normal Bone Tissue

In this paper there are presented determination methods of longitudinal elasticity modulus based on processing and analysis of vibration signals which are the results of an impulse from a small rigid ball applied on some samples of hydroxyapatite with discoid form. Hydroxyapatite is a bioactive bioceramics used, usually in implants, rods and screws covering, in order to allow human tissue to adhere to implant surface. In order to improve mechanical properties of hydroxyapatite it is doped with magnesium. This chemical element exists in normal bone tissue; it doesnt create any compatibility problem and has a stabilizing role in heat treatments stopping undesirable phase transformations.

Indenter Tip Dependence in the Determination of Elastic Modulus in Polymers

2013 ◽  
Author(s):  
Seyed Hamid Reza Sanei ◽  
F. Alisafaei ◽  
Chung-Souk Han
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Elastic Modulus ◽  
Indentation Depth ◽  
Length Scale ◽  
Berkovich Indenter ◽  
Thin Wires ◽  
Length Scale Dependent Deformation ◽  
Nanoindentation Experiment

The two most common outputs of nanoindentation experiment are hardness and elastic modulus. Length scale dependent deformation in polymers has however been observed in different experiments such as microbeam bending, torsional thin wires and indentation testing which may affect the mechanical testing. Unlike in metals where the size dependency is attributed to necessary geometry dislocations, the origin of length scale dependent deformation in polymers is not well understood. In this study, elastic modulus of polydimethylsiloxane (PDMS) is determined using both Berkovich and spherical tips. Observing different trends for elastic modulus upon the change of indentation depth using these two different tips brings up the question which tip should be used to get the real mechanical properties of PDMS which is discussed here. Surface roughness, surface effects and the imperfection of the Berkovich indenter tip are negligible at the studied length scale.

Energy dissipated during spherical indentation

2004 ◽  
Vol 19 (6) ◽  
pp. 1605-1607 ◽  
Author(s):  
Jürgen Malzbender
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Strain Hardening ◽  
Contact Area ◽  
Indentation Depth ◽  
Dissipated Energy ◽  
Spherical Indentation ◽  
Scaling Relationships ◽  
Energy Dissipated

A relationship is derived for spherical indentation relating the dissipated energy to the ratio of hardness to elastic modulus and the ratio of indentation depth to radius. The result agrees with recent findings obtained on the basis of scaling relationships in combination with finite element simulations. Furthermore, relationships are given for hardness, elastic modulus and contact area, which permit a determination of these properties independent of the strain hardening characteristics and independent of pileup and sink-in.

Sign in / Sign up

Export Citation Format

Share Document