PS0003-167 Measurement of the longitudinal elastic modulus of wood by the indentation test using a ball indenter

2015 ◽  
Vol 2015 (0) ◽  
pp. _PS0003-16-_PS0003-16
Author(s):  
Tetsuya HIGASHI ◽  
Tomoaki TSUJI
Keyword(s):  
Elastic Modulus ◽  
Indentation Test ◽  
Longitudinal Elastic Modulus

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 An Upper Bound of Longitudinal Elastic Modulus for Unidirectional Fibrous Composites as Obtained from Strength of Materials Approach

2018 ◽  
Author(s):  
John Venetis ◽  
Emilio Sideridis
Keyword(s):  
Elastic Modulus ◽  
Upper Bound ◽  
Theoretical Models ◽  
The Novel ◽  
Fibrous Composites ◽  
Strength Of Materials ◽  
Fiber Concentration ◽  
Longitudinal Elastic Modulus ◽  
The Matrix ◽  
Specific Variation

In this paper, an upper bound of the longitudinal elastic modulus of  unidirectional   fibrous composites is proposed according to strength of materials approach, on the premise that the fiber is much stiffer than the matrix. In the mathematical derivations, the concept of boundary interphase between fiber and matrix was also taken into account and the main objective of this work is the attainment of an upper bound for the interphase stiffness with respect to fiber concentration by volume. The novel element here is that the authors have not taken into consideration any specific variation law to approximate the interphase modulus. The theoretical results arising from the proposed formula were compared with those obtained from some reliable theoretical models as well as with experimental data found in the literature, and a satisfactory agreement was observed.

Use of combined elastic modulus in depth-sensing indentation with a conical indenter

2003 ◽  
Vol 18 (5) ◽  
pp. 1043-1045 ◽  
Author(s):  
A. C. Fischer-Cripps
Keyword(s):  
Elastic Modulus ◽  
Test Data ◽  
Data Use ◽  
Indentation Test ◽  
Indentation Testing ◽  
Depth Sensing ◽  
Conical Indenter ◽  
Displacement Response ◽  
Conventional Methods ◽  
Elastic Unloading

Conventional methods of analysis for depth-sensing indentation test data use the slope of the elastic unloading portion of the load–displacement response in conjunction with the elastic equations of contact for a rigid cone. It is common practice to incorporate the combined modulus of the indenter and specimen in these equations although the validity of this practice never appears to have been verified. This work demonstrates the validity of using the combined elastic modulus in depth-sensing indentation testing in conjunction with the elastic equations of contact for a conical indenter.

Out-of-Plane Longitudinal Elastic Modulus of Supported Polymer Thin Films

2009 ◽  
Vol 42 (18) ◽  
pp. 7164-7167 ◽  
Author(s):  
N. Gomopoulos ◽  
W. Cheng ◽  
M. Efremov ◽  
P. F. Nealey ◽  
G. Fytas
Keyword(s):  
Thin Films ◽  
Elastic Modulus ◽  
Polymer Thin Films ◽  
Longitudinal Elastic Modulus ◽  
Out Of Plane

Study of the Ion Nitrided Layer on Ti-6Al-4V Substrate

2009 ◽  
Vol 79-82 ◽  
pp. 695-698
Author(s):  
Xiu Yan Li ◽  
Jiao Rong Ye ◽  
Bin Tang
Keyword(s):  
Elastic Modulus ◽  
Titanium Alloys ◽  
Indentation Depth ◽  
Substrate Surface ◽  
Nitrided Layer ◽  
Flux Ratio ◽  
Indentation Test ◽  
Hard Coatings ◽  
Ion Nitriding ◽  
Nano Indentation

Titanium alloys are often material of choice for aerospace, chemical and biomedical industries, because of their unusual corrosion resistance, high mechanical strength and low density. However titanium alloys have very poor wear resistance. Hard coatings can be formed on the surface of titanium alloys to improve their tribological property. In this work ion nitriding without hydrogen technique was used to treat Ti-6Al-4V alloy and the nitrided layer was formed on the substrate surface. The fundamental coating properties, such as the phase, component, hardness and elastic modulus were investigated. At the ion-nitriding condition of flux ratio N2/Ar=1:1, pressure 40 pa and substrate temperature 900°C, the nitrided layer was formed. The layer consists of Ti2N and TiN compound. The content of element nitrogen in the nitrided layer gradiently decreases from the the surface to the substrate direction. For a better understanding of the hardness of the nitrided layer, the nano indentation test and microhardness test are both used. The results show that the average values of hardness and elastic modulus for the surface of the nitrided layer are 17.36GPa and 328.81GPa, about 6 times and 3 times respectively as those of Ti-6Al-4V substrate. The hardness of the nitrided layer decreases from the surface to the substrate direction, which corresponding to the content change of element nitrogen. For the result of nano indentation test, when the indentation depth is more than 400nm, the values of hardness and elastic modulus both decrease with the increase of the indentation depth. It is because of the influence of the soft Ti-6Al-4V substrate.

scholarly journals Assessment of the arterial stiffness in patients with acute ischemic stroke using longitudinal elasticity modulus measurements obtained with Shear Wave Elastography.

2016 ◽  
Vol 18 (2) ◽  
pp. 182 ◽  
Author(s):  
Zhaojun Li ◽  
Lianfang Du ◽  
Feng Wang ◽  
Xianghong Luo
Keyword(s):  
Ischemic Stroke ◽  
Elastic Modulus ◽  
Arterial Stiffness ◽  
Shear Wave ◽  
Arterial Wall ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Shear Wave Elastography ◽  
Bilateral Carotid ◽  
Longitudinal Elastic Modulus

Aim: Arterial wall elasticity including the circumferential and longitudinal modulus is a measure of sub-clinical cardiovascular disease; the circumferential modulus is increased in acute ischemic stroke (AIS). There are still no reports of non-invasive measurement of longitudinal elastic modulus of arterial wall and its prospect of clinical application. In this study, the longitudinal elastic modulus of the arterial wall was assessed using real-time shear wave elastography in patients with AIS. The technique’s feasibility and its related factors were studied initially. Materials and methods: In this study 179 patients with AIS and 168 age- and sex-matched controls were examined. The pulse wave velocity (PWV) of the bilateral carotid arteries was measured using radio frequency ultrasound technology. The 20 areas of superficial walls of bilateral carotid artery were analyzed by real-time shear wave elastography (SWE), and the average values of longitudinal average elastic modulus (MEmean), maximum elastic modulus (MEmax), minimum elastic modulus (MEmin), and elastic modulus standard deviation (MESD) were measured. Results: The PWV, MEmean, MEmax and MESD of the carotid artery in patients with AIS were greater than those in the control group. Age, systolic blood pressure, PWV, and low-density lipoprotein were positively related to MEmean and MEmax (r=0.221and r=0.248, r=0.174 and r=0.176, r=0.776 and r=0.716, r=0.173 and r=0.200, p<0.05) and were independent risk factors for MEmean and MEmax。ROC curves for detection of ischemic stroke as decided by PWV, MEmean and MEmax. The area under the curves were 0.55±0.03 (p≤0.05), 0.59±0.03 (p≤0.05) and 0.60±0.03 (p=0.023), respectively. The optimal PWV, MEmean and MEmax cutoff values for the detection of ischemic stroke were 9.66 m/s, 55.4 kPa and 65.4 kPa, with 69%, 73% and 73% sensitivity and 89%, 53% and 51% specificity, respectively. Conclusions: SWE could measure non-invasively the longitudinal elastic modulus of the arterial wall and evaluate the arterial stiffness. It was equivalent to the PWV which showed circular elastic modulus of arterial wall on evaluating AIS. Age, systolic blood pressure, pulse wave velocity, and low-density lipoprotein were independent risk factors for longitudinal elastic modulus. SWE may be effective in the assessment of arterial stiffness and offer a potential clinical benefit.

scholarly journals Evaluation of Synergic Potential of rGO/SiO2 as Hybrid Filler for BisGMA/TEGDMA Dental Composites

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3025
Author(s):  
Ali Alrahlah ◽  
Rawaiz Khan ◽  
Abdel-Basit Al-Odayni ◽  
Waseem Sharaf Saeed ◽  
Leonel S. Bautista ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Elastic Modulus ◽  
Rheological Properties ◽  
Indentation Test ◽  
Control Group ◽  
Indentation Hardness ◽  
Hybrid Filler ◽  
Nano Indentation ◽  
Base Composite ◽  
Surface Modified

Graphene and graphene oxide based nanomaterials have attained immense significance in research because of their matchless physiochemical characteristics. Although potential biomedical applications of graphene have been extensively studied, however, dentistry related applications were rarely explored. This study aimed to investigate the effect of various percentages of surface modified reduce graphene oxide (S-rGO) in combination with SiO2 nanoparticles (bulk filler) on numerous physio-mechanical characteristics of acrylate-based (BisGMA/TEGDMA: 1:1 by wt.) composites. BisGMA/TEGDMA reinforced with 30 wt.% surface modified fumed-silica (S-A200) was considered as control group (base composite). Various concentrations (0, 0.5, 1, 2, 4 wt.%) of S-rGO were incorporated into the base composite via solution casting and high-speed mixing. The obtained composites were characterized for rheological properties before curing by using Rheometer (Anton Paar, USA) in the oscillatory mode under a frequency sweep over a range of angular frequency of 0.1–100 rad/s at 25 °C. The degree of conversion (DC) was measured by using Fourier transform infrared spectroscopy (FTIR). A Nano-indentation test was carried out to obtain nano-hardness and elastic modulus. The surface roughness was measured by optical microscope (Bruker®), 3D non-contact surface profilometer. The structural and morphological properties were studied by using Scanning Electron Microscopy (SEM). The mean and standard deviation were calculated and a simple mean comparisons test was performed for comparison using SPSS. The results revealed that the addition of a tiny proportion of S-rGO considerably increased the nano-indentation hardness, elastic modulus and DC. Conversely, a gradual reduction in viscosity was observed with increasing S-rGO concentration. The study demonstrates that a small fraction of S-rGO in combination with SiO2 could enhance physical, mechanical and rheological properties of acrylate based composites. Thus S-rGO/SiO2 combination could be used as a potential hybrid filler for dental nanocomposites.

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