scholarly journals The Effects of Creep on Elastic Modulus Measurement Using Nanoindentation

2000 ◽  
Vol 649 ◽  
Author(s):  
G. Feng ◽  
A.H.W. Ngan
Keyword(s):  
Elastic Modulus ◽  
Elastic Deformation ◽  
Elastic Moduli ◽  
Holding Time ◽  
Time Dependent ◽  
Nanoindentation Test ◽  
Modification Method ◽  
Unloading Rate ◽  
Modulus Measurement

ABSTRACTDuring the unloading segment of nanoindentation, time dependent displacement (TDD) accompanies elastic deformation. Consequently the modulus calculated by the Oliver-Pharr scheme can be overestimated. In this paper we present evidences for the influence of the measured modulus by TDD. A modification method is also presented to correct for the effects of TDD by extrapolating the TDD law in the holding process to the beginning of the unloading process. Using this method, the appropriate holding time and unloading rate can be estimated for nanoindentation test to minimise the effects of TDD. The elastic moduli of three materials computed by the modification method are compared with the results without considering the TDD effects.

Mechanical properties and creep behavior of lyocell fibers by nanoindentation and nano-tensile testing

Holzforschung ◽  
2007 ◽  
Vol 61 (3) ◽  
pp. 254-260 ◽  
Author(s):  
Seung-Hwan Lee ◽  
Siqun Wang ◽  
George M. Pharr ◽  
Matthew Kant ◽  
Dayakar Penumadu
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Tensile Testing ◽  
Holding Time ◽  
Time Dependent ◽  
Nanoindentation Test ◽  
Creep Equation ◽  
Mean Values ◽  
Significant Difference ◽  
Lyocell Fibers

Abstract Mechanical and time-dependent mechanical properties of lyocell fibers have been investigated as a function of depth at a nano-scale level in longitudinal and transverse directions. The nanoindentation technique was applied and extended to continuous stiffness measurement. Lyo10 and Lyo13 lyocell fibers were investigated. The individual fiber properties were measured using a nano-tensile testing system to obtain reference data for mechanical properties. The hardness and elastic modulus obtained from nanoindentation test are described using two different approaches. The first uses mean values for a depth of 150–300 nm, while the second uses unloading values at the final indentation depth. There is no significant difference between modulus values inferred from nanoindentation and those obtained from single fiber tensile testing. Hardness and elastic modulus values were higher in the longitudinal direction than those in the transverse direction and Lyo13 values were higher than those for Lyo10 in both directions. The time-dependent mechanical properties were also investigated as a function of the holding time. Increasing the holding time led to an increase in indentation displacement and a decrease in hardness. Stress exponents were calculated from the linear relationship between contact stress and contact strain using a power-law creep equation.

scholarly journals Elastic Modulus, Thermal Expansion, and Pyrolysis Shrinkage of Norway Spruce Under High Temperature

2021 ◽  
Author(s):  
Tito Adibaskoro ◽  
Michalina Makowska ◽  
Aleksi Rinta-Paavola ◽  
Stefania Fortino ◽  
Simo Hostikka
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Elastic Modulus ◽  
Norway Spruce ◽  
Elastic Moduli ◽  
Elevated Temperatures ◽  
Ambient Air ◽  
Time Dependent ◽  
Temperature History ◽  
Direction Parallel

AbstractThe orthotropic and temperature-dependent nature of the mechanical properties of wood is well recognized. However, past studies of mechanical properties at elevated temperatures are either limited to temperatures below 200 °C or focus only on the direction parallel to grain. The effect of time-dependent pyrolysis during measurement is often neglected. This paper presents a novel method for determining elastic modulus at high temperatures and thermal expansion coefficient in different orthotropic directions via Dynamic Mechanical-Thermal Analyser (DMTA). The method allows for drying, drying verification, and measurement in one chamber, eliminating the possibility of moisture reabsorption from ambient air. The repeatable measurements can be carried out in temperatures up to 325°C, adequate for observing time-dependent pyrolysis during measurement. Results of the measurements of Norway Spruce provide data of its mechanical response at temperature range previously not explored widely, as well as in the orthotropic direction. Time-dependent behaviour was observed in the thermal expansion and shrinkage experiment, where above 250°C the amount of shrinkage depends on heating rate. At such temperature, elastic moduli measurement also shows time dependence, where longer heating at certain temperature slightly increases the measured elastic modulus. Additionally, bilinear regression of the relationship between elastic moduli and temperature shows quantitatively good fit. Numerical simulation of the DMTA temperature history and wood chemical components mass losses show the onset of shrinkage and onset of hemicellulose mass loss occurring at around the same time, while decomposition of cellulose correlate with the sudden loss of elastic moduli.

Elastic and Anelastic Behavior of Materials in Small Dimensions

MRS Bulletin ◽  
2002 ◽  
Vol 27 (1) ◽  
pp. 26-29 ◽  
Author(s):  
Shefford P. Baker ◽  
Richard P. Vinci ◽  
Tomás Arias
Keyword(s):  
Elastic Deformation ◽  
Elastic Moduli ◽  
Time Dependent ◽  
Elastic Behavior ◽  
Small Deviations ◽  
Reversible Deformation ◽  
Special Cases ◽  
Bond Stretching ◽  
Anelastic Behavior ◽  
Bulk Behavior

AbstractUnder certain circumstances, decreasing the dimensions of a material may lead to elastic or anelastic properties that diverge from bulk behavior. A distinction is made between elastic deformation, for which bond rearrangements are not required, and anelastic behavior, which involves reversible deformation due to defect motion. Elastic deformation (due to bond stretching) remains structure-insensitive down to near-atomic length scales, and only small deviations are expected (of the order of 10%). More significant deviations can be observed in special cases, which are described in the article. However, elastic moduli that are much lower than expected are sometimes seen, even in careful experiments. It now appears that this behavior may be explainable by time-dependent anelastic relaxation mechanisms. In contrast to purely elastic behavior, anelastic behavior is very sensitive to microstructure and is found to be common and often significant when things become small.

Evolution of Crystallographic Texture and Mechanical Properties during Annealing of Nanocrystalline Fe-50%Ni Alloy Foil

2007 ◽  
Vol 345-346 ◽  
pp. 781-784
Author(s):  
Jong Kweon Kim ◽  
Shi Hoon Choi ◽  
Yong Bum Park
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Crystallographic Texture ◽  
Elastic Moduli ◽  
Nanoindentation Test ◽  
Strong Decrease ◽  
Alloy Foil ◽  
Ni Alloy ◽  
Self Consistent ◽  
Good Agreement

The crystallographic texture and mechanical properties were investigated in a nanocrystalline Fe-50%Ni alloy fabricated by using an electrodeposition method. The as-deposited texture was characterized by strong <100>//ND and weak <111>//ND fibre components, and the occurrence of grain growth resulted in the strong development of the <111>//ND fibre components with the minor <100>//ND fibre components. The elastic modulus and hardness were measured by means of a nanoindentation test. The annealing led the specimen to an increase in the elastic modulus and a strong decrease in the hardness. The elastic modului measured were compared with the theoretic predictions based on an elastic self-consistent (ESC) polycrystal model. The theoretical values of the elastic moduli through the thickness direction in the sample were in a good agreement with the experimental results.

scholarly journals A harmless thin film elastic modulus measurement method through bending the nonlinear sliding cantilever beam

Measurement ◽  
2021 ◽  
Vol 175 ◽  
pp. 108984
Author(s):  
Jianhua Tang ◽  
Lezhang Liu ◽  
Li Jiang ◽  
Hui Huang ◽  
Qiongyao Wang
Keyword(s):  
Thin Film ◽  
Elastic Modulus ◽  
Cantilever Beam ◽  
Measurement Method ◽  
Modulus Measurement

scholarly journals Elastic modulus measurement of ultrathin layer using gas cluster ion beam

2021 ◽  
Vol 15 (6) ◽  
pp. JAMDSM0076-JAMDSM0076
Author(s):  
Hiroshi TANI ◽  
Renguo LU ◽  
Shinji KOGANEZAWA ◽  
Norio TAGAWA
Keyword(s):  
Elastic Modulus ◽  
Ion Beam ◽  
Cluster Ion ◽  
Modulus Measurement ◽  
Gas Cluster Ion Beam ◽  
Ultrathin Layer

scholarly journals Elastic modulus measurement of thermoplastic composites through modal analysis

2021 ◽  
Vol 1189 (1) ◽  
pp. 012020
Author(s):  
B Harshavardhan ◽  
R Ravishankar ◽  
B Suresha ◽  
U Arun C Dixit
Keyword(s):  
Elastic Modulus ◽  
Modal Analysis ◽  
Thermoplastic Composites ◽  
Modulus Measurement

scholarly journals Evaluation Method of Granite Multiscale Mechanical Properties Based on Nanoindentation Technology

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Man Lei ◽  
Fa-ning Dang ◽  
Haibin Xue ◽  
Mingming He
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Uniaxial Compression ◽  
Compression Test ◽  
Evaluation Method ◽  
Poisson Ratio ◽  
Nanoindentation Test ◽  
Uniaxial Compression Test ◽  
Displacement Curve ◽  
Mineral Contents

In order to study the mechanical properties of granite at the micro- and nanoscale, the load-displacement curve, residual indentation information, and component information of the quartz, feldspar, and mica in granite were obtained using a nanoindentation test, a scanning electron microscope (SEM), and X-ray diffraction (XRD). The elastic modulus and the hardness of each component of the granite were obtained through statistical analysis. Treating rock as a composite material, the relation between the macro- and microscopic mechanical properties of rock was established through the theory of micromechanical homogenization. The transition from micromechanical parameters to macromechanical parameters was realized. The equivalent elastic modulus and Poisson’s ratio of the granite were obtained by the Self-consistent method, the Dilute method, and the Mori-Tanaka method. Compared with the elastic modulus and the Poisson ratio of granites measured by a uniaxial compression test and the available data, the applicability of the three methods were analyzed. The results show that the elastic modulus and hardness of the quartz in the granite is the largest, the feldspar is the second, the mica is the smallest. The main mineral contents in granite were analyzed using the semiquantitative method by XRD and the rock slice identification test. The elastic modulus and the Poisson ratio of granite calculated by three linear homogenization methods are consistent with those of the uniaxial compression test. After comparing the calculation results of the three methods, it is found that the Mori-Tanaka method is more suitable for studying the mechanical properties of rock materials. This method has an important theoretical significance and practical value for studying the quantitative relationship between macro- and micromechanical indexes of brittle materials. The research results provide a new method and an important reference for studying the macro-, micro-, and nanomechanical properties of rock.

Consistent red luminescence in π-conjugated polymers with tuneable elastic moduli over five orders of magnitude

2020 ◽  
Vol 7 (5) ◽  
pp. 1421-1426 ◽  
Author(s):  
Zhenfeng Guo ◽  
Akira Shinohara ◽  
Chengjun Pan ◽  
Florian J. Stadler ◽  
Zhonghua Liu ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Conjugated Polymers ◽  
Elastic Moduli ◽  
Luminescent Properties ◽  
Side Chains ◽  
Wide Range ◽  
Alkyl Side Chains ◽  
Red Luminescence

Bulky but flexible alkyl side chains enable π-conjugated polymers to possess wide-range elastic modulus tuneability, yet consistent red luminescent properties.

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