scholarly journals A Focus on Dynamic Modulus: Effects of External and Internal Morphological Features

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 40
Author(s):  
Maria Richetta ◽  
Alessandra Varone
Keyword(s):  
Young’S Modulus ◽  
Dynamic Modulus ◽  
Young's Modulus ◽  
Morphological Features ◽  
Elastic Behavior ◽  
Sintered Steels ◽  
Geometrical Features ◽  
Interconnected Pores ◽  
Low Porosity

The present work examines the effects of external and internal morphological features on the dynamic elastic modulus and its measure. It consists of two parts. The first part considers the effect of geometrical features of probes and shows the key role of roughness as source of a systematic error leading to the underestimation of the Young’s modulus. The second one is focused on the effect of porosity. Several models which consider the porosity as an ideal regular microstructure and the relative equations describing the Young’s modulus vs. porosity have been reviewed and critically discussed. The values of the relative modulus Er predicted by different models are similar for materials with low porosity (p < 0.2) and isolated pores whereas they strongly diverge if p > 0.2 and interconnected pores are present. Moreover, such models fail to describe the elastic behavior of materials correctly also with low porosity (p ≈ 0.1) such as sintered steels in the case of pores with a preferred orientation and an irregular shape.

scholarly journals Microtubules regulate cardiomyocyte transversal Young’s modulus

2020 ◽  
Vol 117 (6) ◽  
pp. 2764-2766 ◽  
Author(s):  
Pamela Swiatlowska ◽  
Jose L. Sanchez-Alonso ◽  
Peter T. Wright ◽  
Pavel Novak ◽  
Julia Gorelik
Keyword(s):  
Young’S Modulus ◽  
Mechanical Loading ◽  
Posttranslational Modifications ◽  
Young's Modulus ◽  
Cardiac Mechanics ◽  
Ion Conductance ◽  
Loading And Unloading ◽  
Microtubular Network ◽  
Significant Attention

The field of cardiomyocyte mechanobiology is gaining significant attention, due to accumulating evidence concerning the significant role of cellular mechanical effects on the integrated function of the heart. To date, the protein titin has been demonstrated as a major contributor to the cardiomyocytes Young’s modulus (YM). The microtubular network represents another potential regulator of cardiac mechanics. However, the contribution of microtubules (MTs) to the membrane YM is still understudied and has not been interrogated in the context of myocardial infarction (MI) or mechanical loading and unloading. Using nanoscale mechanoscanning ion conductance microscopy, we demonstrate that MTs contribute to cardiomyocyte transverse YM in healthy and pathological states with different mechanical loading. Specifically, we show that posttranslational modifications of MTs have differing effects on cardiomyocyte YM: Acetylation provides flexibility, whereas detyrosination imparts rigidity. Further studies demonstrate that there is no correlation between the total protein amount of acetylated and detyrosinated MT. Yet, in the polymerized-only populations, an increased level of acetylation results in a decline of detyrosinated MTs in an MI model.

scholarly journals Short-term angiotensin II treatment regulates cardiac nanomechanics via microtubule modifications

Nanoscale ◽  
2020 ◽  
Vol 12 (30) ◽  
pp. 16315-16329
Author(s):  
Pamela Swiatlowska ◽  
Jose L. Sanchez-Alonso ◽  
Catherine Mansfield ◽  
Denis Scaini ◽  
Yuri Korchev ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Short Term ◽  
Nanoscale Level

MechanoSICM is used to understand the role of angiotensin II on transverse Young's modulus at the nanoscale level.

scholarly journals Role of Corneal Epithelium in Riboflavin/Ultraviolet-A Mediated Corneal Cross-Linking Treatment in Rabbit Eyes

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Xiangchen Tao ◽  
Haiqun Yu ◽  
Yong Zhang ◽  
Zhiwei Li ◽  
Vishal Jhanji ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Corneal Epithelium ◽  
Young's Modulus ◽  
Biomechanical Properties ◽  
Cross Linking ◽  
Control Group ◽  
Ultraviolet A ◽  
Uva Irradiation ◽  
Maximal Stress

Purpose. To evaluate the role of corneal epithelium in riboflavin/ultraviolet-A (UVA) mediated corneal collagen cross-linking treatment.Methods. Fifty New Zealand rabbits were divided into 5 groups: UVA treatment with or without corneal epithelium, UVA+riboflavin treatment with or without corneal epithelium, and control without any treatment. All rabbits were sacrificed after irradiation and subsequently 4 mm × 10 mm corneal strips were harvested for biomechanical evaluation.Results. UVA irradiation alone did not enhance the maximal stress and Young’s modulus of corneal specimens with (3.15 ± 0.56 mpa, 1.00 ± 0.09 mpa) or without (3.53 ± 0.85 mpa, 0.94 ± 0.21 mpa) the corneal epithelium, compared to specimens in the control group (4.30 ± 0.68 mpa, 1.03 ± 0.24 mpa). However, UVA irradiation combined with riboflavin significantly increased the maximal stress and Young’s modulus of corneal specimens with (5.27 ± 1.09 mpa, 1.23 ± 0.23 mpa,P<0.05) or without (7.16 ± 1.88 mpa, 1.42 ± 0.16 mpa,P<0.05) corneal epithelium when compared to the control group. The maximal stress and Young’s modulus of cornea in UVA+riboflavin and “epithelium-off” group were 35.9% and 15.4% higher compared to the UVA+riboflavin and “epithelium-on” group, respectively (P<0.05).Conclusions. Our study shows that UVA+riboflavin treatment significantly affects the biomechanical properties of the cornea with and without epithelial removal. However, corneas without epithelium seem to benefit more compared to corneas with the epithelium.

Micromechanical Characterization of Gasb by Microbeam Deflecion and Using Nanoprobe and Finite Element Analysis

2003 ◽  
Vol 782 ◽  
Author(s):  
M. Ospina ◽  
S. R. Vangala ◽  
D. Yang ◽  
J. A. Sherwood ◽  
C. Sung ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Young’S Modulus ◽  
Gallium Antimonide ◽  
Young's Modulus ◽  
Elastic Behavior ◽  
Material System ◽  
Scaling Effects ◽  
Commercial Development ◽  
Linear Elastic

ABSTRACTThe commercial development of low-power electronics and electro-optics based on antimonides demands a better understanding of the mechanical properties of ternary and quaternary thin-film alloys fabricated from the InGaAlAsSbP material system. Of particular importance is the determination of Young's modulus of these materials. In this paper, a technique for studying the mechanical behavior of these thin films was developed by using microbeam bending and finite element modeling. The technique was successfully applied to investigate the mechanical properties of GaSb. A test structure consisting of an array of gallium antimonide microbeams was fabricated with lengths ranging from 50 to 500 μm long. The microbeams were deflected using a calibrated nanoprobe, thereby generating load-displacement curves. Young's modulus was then extracted from the data using beam bending theory and a finite element simulation of the structures under load. A total of five microbeams with the same trapezoidal cross-section and lengths of 80, 85, 200, 250 and 500 μm were tested to study the technique applicability and size scaling effects on the mechanical properties. It was observed that the 80 and 85 μm beams exhibited linear elastic behavior and the 200, 250, and 500 μm microbeams exhibited non-linear elastic behavior.

Analysis of the Scatter of the Elastic Properties in Conventionally Cast Nickel Base Superalloys: Quantification, Modeling and Evaluation of the Impact on Gas Turbine Blade Design

2014 ◽  
Author(s):  
Andrea Riva ◽  
Andrea Bessone
Keyword(s):  
Gas Turbine ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Turbine Blades ◽  
Mode Shapes ◽  
Elastic Behavior ◽  
Nickel Base Superalloys ◽  
Nickel Base ◽  
The Impact

Cast nickel-base superalloys elastic properties have a very large scatter, mainly because of the coarse grain microstructure and in-grain anisotropy. This high dispersion must be taken into account in the design of gas turbine blades, in particular when evaluating phenomena directly linked to the elastic behavior, such as blades vibration. This source of elastic properties scatter becomes even more important on specimens for material characterization because of their inferior size, which entails a lesser number of grains (i.e. a larger scatter). In this paper a model aimed to quantify such scatter is proposed. The performances of the model in predicting the standard deviation of the Young’s modulus (and consequently of the eigenfrequencies) are also shown, both for tested specimens and blades excited on clamps. Finally, a sensitivity FEM modal analysis is performed in order to evaluate how the elastic property dispersion might affect the blade eigenfrequencies and the relative mode shapes, with particular emphasis on the case of a specific region of a geometrically complex component affected by an anomalous Young’s modulus. Besides, the influence of the blade mass is evaluated through both experimental clamp impact tests and FEM analyses. The effect on blades of such source of scatter is then compared to the effect of the elastic properties dispersion. ANSYS program has been used for the simulations.

Experimental Research on the Dynamic Young’s Modulus of Specified Density Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 164-167
Author(s):  
Xiao Er Zhou ◽  
Yan Kun Zhang ◽  
De Min Jiang
Keyword(s):  
Young’S Modulus ◽  
Experimental Research ◽  
Vibration Frequency ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Natural Vibration ◽  
Young's Modulus ◽  
Natural Vibration Frequency ◽  
Dynamic Modulus Of Elasticity ◽  
Static Young’S Modulus

From the experimental research, the relations between the dynamic modulus of elasticity and natural vibration frequency of specified density concrete are studied, the static Young’s modulus and dynamic modulus are compared. Based on regression analysis, the influence of different Substitution ratio of lightweight aggregate, age of concrete and cement water ratio is studied. According to the test results, the formula of natural vibration frequency and the dynamic modulus of elasticity of Specified density concrete is given, which provide theory basis for the nondestructive detector of the specified density concrete.

Capillary forces between rigid spheres and elastic supports: the role of Young's modulus and equilibrium vapor adsorption

Soft Matter ◽  
2013 ◽  
Vol 9 (17) ◽  
pp. 4534 ◽  
Author(s):  
Marjan Zakerin ◽  
Michael Kappl ◽  
Ellen H. G. Backus ◽  
Hans-Jürgen Butt ◽  
Friedhelm Schönfeld
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Capillary Forces ◽  
Rigid Spheres ◽  
Elastic Supports ◽  
Vapor Adsorption
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