scholarly journals Time and frequency dependent mechanical properties of LaCoO3-based perovskites: Internal friction and negative creep

2018 ◽  
Vol 124 (20) ◽  
pp. 205103 ◽  
Author(s):  
Mykola Lugovy ◽  
Nina Orlovskaya ◽  
Siddhartha Pathak ◽  
Miladin Radovic ◽  
Edgar Lara-Curzio ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Internal Friction ◽  
Frequency Dependent ◽  
Negative Creep

scholarly journals Time and frequency dependent mechanical properties of LaCoO3-based perovskites: Neutron diffraction and domain mobility

2018 ◽  
Vol 124 (20) ◽  
pp. 205104 ◽  
Author(s):  
Mykola Lugovy ◽  
Amjad Aman ◽  
Nina Orlovskaya ◽  
Viktor Slyunyayev ◽  
Thomas Graule ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Neutron Diffraction ◽  
Frequency Dependent

scholarly journals Analysis of the Mechanical Properties of N-Added CMn Structural Steel by the Impulse Internal Friction Technique

2012 ◽  
Vol 43 (12) ◽  
pp. 4587-4600 ◽  
Author(s):  
Jaehyuk Jung ◽  
E. Kozeschnik ◽  
Seong Ho Han ◽  
Bruno C. De Cooman
Keyword(s):  
Mechanical Properties ◽  
Internal Friction ◽  
Structural Steel

Friction and Bearing Loads on Buried Pipes

1973 ◽  
Vol 13 (03) ◽  
pp. 163-174
Author(s):  
Alexander Blake ◽  
Maurice Zaslawsky
Keyword(s):  
Mechanical Properties ◽  
Internal Friction ◽  
Applied Stress ◽  
Phase Difference ◽  
Poisson’S Ratio ◽  
Soil Mechanics ◽  
Poisson's Ratio ◽  
Stress Strain ◽  
Physical Constants ◽  
Design Analyses

Abstract Presented here are results of experimental and theoretical investigations of the behavior of downhole pipe, surrounded by Overton sand or gravel, when subjected to shock from nuclear explosion. The principal effects investigated arelongitudinal friction between the pipe and the stemming material andresistance offered by the stemming material to transverse motion of the pipe. Introduction Stemming materials such as Overton sand and pea gravel are widely used in underground nuclear pea gravel are widely used in underground nuclear testing to ensure containment of the explosion. Present-day theories of mechanics suitable for predicting stresses and displacements within an predicting stresses and displacements within an array of particles of such materials are rather limited because of the stress-strain-time behavior and complicated boundary conditions involved. Thus, measurements representing gross effects only and linearized models of analysis must be relied upon in making the majority of engineering decisions where soil-structure interactions are encountered. Furthermore, because of the number of variables and hardware constraints present in designing deep-hole emplacement systems, the emphasis should be on obtaining experimental data on fullscale or nearly full-scale structural components in association with stemming materials of actual field quality. The experiment discussed in this paper was directed toward the development of basic mechanical properties such as modulus of elasticity, friction characteristics during axial (longitudinal) pipe motion through stemming materials, resistance pipe motion through stemming materials, resistance of stemming materials to transverse pipe displacement, and related physical phenomena that may have further bearing on the usual mechanical properties employed in various design analyses. properties employed in various design analyses. During evaluation of the basic mechanical properties, an attempt was made to develop a properties, an attempt was made to develop a Poisson's ratio type of data for the stemming Poisson's ratio type of data for the stemming materials at hand by using both specialized equipment and standard test equipment normally employed in soil mechanics. The results of the study, however, should be interpreted with due regard to the particulate nature of stemming materials, which do not represent a continuum with well defined stress-strain relationships. To obtain meaningful data on friction and transverse resistance characteristics, a special test rig was designed with particular emphasis on minimizing the scale effects and experimental errors usually encountered. In mechanics the term "friction" is the resistance to motion of two moving objects or surfaces that touch. In this paper we speak of several different types of micron, and therefore some clarification is needed. The friction between sand or gravel and the down-hole pipe as we attempt to move the pipe is one type of friction. A similar type is the friction developed between sand or gravel and the steel block it rubs against in the direct shear test apparatus. Those two examples of friction are rather straightforward, however, the following two present some confusion because they are both referred to as internal friction:Internal friction as used by engineering scientists, physicists, and metallurgists may be defined as the conversion of the mechanical energy of a vibrating solid into heat. This is also referred to as the damping capacity and corresponds to a phase difference between the applied stress and phase difference between the applied stress and its resultant strain.b soil mechanics the concept of internal friction corresponds to friction between the surfaces of individual grains of sand or gravel. In granular materials, both kinds of internal friction occur. In this paper the term "internal friction" is referred to extensively and is used exclusively in the sense of friction between particles. particles. FUNDAMENTALS OF SOIL MECHANICS The mechanical behavior of earth materials such as sand or gravel can be described by suitable physical constants reflecting certain physical constants reflecting certain stress-deformation relations that may then be applied in customary engineering predictions. In dealing with the rigidity of rocks, Young's modulus, E, and Poisson's ratio, are commonly used, and soil Poisson's ratio, are commonly used, and soil mechanics utilizes basic concepts of the theory of elasticity. By analogy to this well established practice, related concepts utilizing elastic practice, related concepts utilizing elastic constants in loading and unloading can be made applicable to stemming materials. SPEJ P. 163

A Novel In-Situ Nanoindentation Characterization of Phase Transforming Materials

2015 ◽  
Vol 1754 ◽  
pp. 19-24
Author(s):  
A. Alipour Skandani ◽  
R. Ctvrtlik ◽  
M. Al-Haik
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
Creep Compliance ◽  
Physical And Mechanical Properties ◽  
In Situ Methods ◽  
Negative Creep ◽  
Nanoindentation Instrument ◽  
Structural Instabilities

ABSTRACTMaterials with different allotropes can undergo one or more phase transformations based on the changes in the thermodynamic states. Each phase is stable in a certain temperature/pressure range and can possess different physical and mechanical properties compared to the other phases. The majority of material characterizations have been carried out for materials under equilibrium conditions where the material is stabilized in a certain phase and a lesser portion is devoted for onset of transformation. Alternatively, in situ measurements can be utilized to characterize materials while undergoing phase transformation. However, most of the in situ methods are aimed at measuring the physical properties such as dielectric constant, thermal/electrical conductivity and optical properties. Changes in material dimensions associated with phase transformation, makes direct measurement of the mechanical properties very challenging if not impossible. In this study a novel non-isothermal nanoindentation technique is introduced to directly measure the mechanical properties such as stiffness and creep compliance of a material at the phase transformation point. Single crystal ferroelectric triglycine sulfate (TGS) was synthetized and tested with this method using a temperature controlled nanoindentation instrument. The results reveal that the material, at the transformation point, exhibits structural instabilities such as negative stiffness and negative creep compliance which is in agreement with the findings of published works on the composites with ferroelectric inclusions.

scholarly journals Magnesium Reinforced with Inconel 718 Particles Prepared Ex Situ—Microstructure and Properties

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 798
Author(s):  
Zuzanka Trojanová ◽  
Zdeněk Drozd ◽  
Pavel Lukáč ◽  
Peter Minárik ◽  
Gergely Németh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Internal Friction ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Inconel 718 ◽  
Hot Extrusion ◽  
Fiber Texture ◽  
Ex Situ ◽  
Tension And Compression

Magnesium samples reinforced with 0.7, 1.4, and 2.4 vol.% of Inconel 718 particles were prepared using a disintegrated melt deposition technique followed by hot extrusion. Mechanical properties, thermal expansion, and damping were studied with the aim of revealing the particle influence on the microstructure, texture, tensile and compressive behavior, thermal expansion coefficient, and internal friction. The flow stresses are significantly influenced by the test temperature and the vol.% of particles. A substantial asymmetry in the tensile and compressive properties was observed at lower temperatures. This asymmetry is caused by different deformation mechanisms operating in tension and compression. The fiber texture of extruded composite samples, refined grain sizes, and the increased dislocation density improved the mechanical properties. On the other hand, a decrease in the thermal expansion coefficient and internal friction was observed.

scholarly journals Energy localization and frequency analysis in the locust ear

2014 ◽  
Vol 11 (90) ◽  
pp. 20130857 ◽  
Author(s):  
Robert Malkin ◽  
Thomas R. McDonagh ◽  
Natasha Mhatre ◽  
Thomas S. Scott ◽  
Daniel Robert
Keyword(s):  
Mechanical Properties ◽  
Signal Analysis ◽  
Structural Features ◽  
Dependent Manner ◽  
Sound Waves ◽  
Energy Localization ◽  
Frequency Signal ◽  
Element Analysis ◽  
Frequency Dependent ◽  
Necessary And Sufficient

Animal ears are exquisitely adapted to capture sound energy and perform signal analysis. Studying the ear of the locust, we show how frequency signal analysis can be performed solely by using the structural features of the tympanum. Incident sound waves generate mechanical vibrational waves that travel across the tympanum. These waves shoal in a tsunami-like fashion, resulting in energy localization that focuses vibrations onto the mechanosensory neurons in a frequency-dependent manner. Using finite element analysis, we demonstrate that two mechanical properties of the locust tympanum, distributed thickness and tension, are necessary and sufficient to generate frequency-dependent energy localization.

Reduction in transmembrane Ca influx induced by the negative inotropic action of nicardipine in frog ventricular muscle

1986 ◽  
Vol 64 (7) ◽  
pp. 927-930
Author(s):  
Junna Hatae
Keyword(s):  
Mechanical Properties ◽  
Action Potential ◽  
Resting Potential ◽  
Ventricular Muscle ◽  
Inotropic Action ◽  
Frequency Dependent ◽  
High Frequencies ◽  
Dihydropyridine Derivative

The effects of nicardipine, a new 1,4-dihydropyridine derivative, on electrical and mechanical properties of frog ventricular muscle were examined. Nicardipine (3 × 10−7 M) reduced the twitch tension, and this reduction was frequency dependent, and considerable, in case of high frequencies. The resting potential was not affected by nicardipine (3 × 10−7 M), but the plateau height of the action potential was decreased and the duration of the action potential was shortened. The suppression of this plateau height was frequency dependent. The nicardipine-induced suppression of tension and action potential could be almost completely antagonized by raising the concentration of [Ca]o or by applying isoprenaline (8 × 10−7 M). These results suggest that the negative inotropic action of nicardipine is induced mainly by a reduction in the transmembrane Ca influx.

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