scholarly journals Release of elastic strain energy as acoustic emission during the reverse thermoelastic phase transformation in Au-47.5 at .% Cd alloy

1980 ◽  
Vol 14 (9) ◽  
pp. 1013-1016 ◽  
Author(s):  
J. Baram ◽  
J. Avissar ◽  
Y. Gefen ◽  
M. Rosen
Keyword(s):  
Acoustic Emission ◽  
Phase Transformation ◽  
Elastic Strain ◽  
Strain Energy ◽  
Elastic Strain Energy ◽  
Thermoelastic Phase Transformation

scholarly journals Experimental Investigation of Early-Warning Critical Energy for Strainbursts

2021 ◽  
Author(s):  
Wang Ling ◽  
Ruyu Yan ◽  
Zhang zhi ◽  
Xie Lei ◽  
Huang chuhui
Keyword(s):  
Acoustic Emission ◽  
Energy Dissipation ◽  
Early Warning ◽  
Elastic Strain ◽  
Strain Energy ◽  
Triaxial Compression ◽  
Elastic Strain Energy ◽  
Critical Energy ◽  
Input Energy ◽  
Energy Evolution

Abstract This research aimed to establish an early-warning critical energy for coal instability based on the energy theory and acoustic emission characteristics of coal under triaxial compression. To obtain an early-warning critical strain energy indicating the increase in the risk of coal instability, conventional triaxial compression and acoustic emission (AE) tests were carried out on coal specimens taken from a 980-m-deep mine with initial confining pressures of 10, 15, 20, 25, 30 and 35 MPa. Stress-strain relations, AE features, and energy evolution characteristics during triaxial compression were analyzed. It was found that the energy evolution and AE event count changes across different loading stages. With increasing axial stress, most of the input energy stored in the coal specimens was in the form of elastic strain energy and the AE event count was close to zero, indicating that the coal grains reach a state of balance. After the elastic deformation stage, a portion of the input energy was consumed by inelastic deformation. Once the stress level exceeded the volumetric compressibility–dilatancy transition stress, the AE event entered a period of relative quiet, and the rate of energy dissipation abruptly accelerated, indicating that the coal grains achieved another state of balance before THE instability or failure. The balance of the rock grains is broken again (AE event count and the rate of energy dissipation both increased dramatically), coal achieved the peak strength and instability soon. The point at which the dissipated energy ratio α increased rapidly or the starting point of a quiet period, indicates an increase in the risk of coal instability. The corresponding elastic strain energy accumulated within the coal can be regarded as a precursor to instability or strainburst. Accordingly, a fitting formula is presented to predict the early-warning critical energy for brittle coal subject to different minimum principal stress. The analysis results in this paper can be helpful in the assessment of coal instability risk.

Correlation Among the Variant Group, Effective Grain Size, and Elastic Strain Energy During the Phase Transformation in 9Ni Steels

2017 ◽  
Vol 48 (12) ◽  
pp. 5761-5765 ◽  
Author(s):  
Hidenori Terasaki ◽  
Koji Moriguchi ◽  
Yusaku Tomio ◽  
Hideki Yamagishi ◽  
Shigekazu Morito
Keyword(s):  
Grain Size ◽  
Phase Transformation ◽  
Elastic Strain ◽  
Strain Energy ◽  
Elastic Strain Energy ◽  
Effective Grain Size

Do muscles function as adaptable locomotor springs?

2002 ◽  
Vol 205 (15) ◽  
pp. 2211-2216 ◽  
Author(s):  
Stan L. Lindstedt ◽  
Trude E. Reich ◽  
Paul Keim ◽  
Paul C. LaStayo
Keyword(s):  
Skeletal Muscle ◽  
Elastic Strain ◽  
Strain Energy ◽  
Elastic Strain Energy ◽  
Normal Animal ◽  
Eccentric Contractions ◽  
Normal Muscle ◽  
Energetic Costs ◽  
Locomotor Muscles ◽  
Power Outputs

SUMMARYDuring normal animal movements, the forces produced by the locomotor muscles may be greater than, equal to or less than the forces acting on those muscles, the consequences of which significantly affect both the maximum force produced and the energy consumed by the muscles. Lengthening (eccentric)contractions result in the greatest muscle forces at the lowest relative energetic costs. Eccentric contractions play a key role in storing elastic strain energy which, when recovered in subsequent contractions, has been shown to result in enhanced force, work or power outputs. We present data that support the concept that this ability of muscle to store and recover elastic strain energy is an adaptable property of skeletal muscle. Further, we speculate that a crucial element in that muscle spring may be the protein titin. It too seems to adapt to muscle use, and its stiffness seems to be`tuned' to the frequency of normal muscle use.

The Elastostatic Axisymmetric Problem of a Cracked Sphere Embedded in a Dissimilar Matrix

1980 ◽  
Vol 47 (3) ◽  
pp. 545-550 ◽  
Author(s):  
R. Kant ◽  
D. B. Bogy
Keyword(s):  
Elastic Strain ◽  
Strain Energy ◽  
Elastic Strain Energy ◽  
Companion Paper ◽  
Infinite Medium ◽  
Applied Mechanics ◽  
Axisymmetric Solution ◽  
Material Parameters ◽  
The Difference ◽  
Elastostatic Problem

The axisymmetric elastostatic problem of a cracked sphere embedded in a dissimilar matrix is solved by using the solution for a spherical cavity in an infinite medium together with the axisymmetric solution for a cracked sphere given in the companion paper in this issue of the Journal of Applied Mechanics, Pages 538-544. Numerical results are presented for (a) interface stress for various composites (b) dependence of the stress-intensity factor on the material parameters and ratios of crack to sphere radii, (c) the difference in the elastic strain energy for a cracked and uncracked composite.

scholarly journals Effect of Joint Density on Rockburst Proneness of the Elastic-Brittle-Plastic Rock Mass

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jiliang Pan ◽  
Fenhua Ren ◽  
Meifeng Cai
Keyword(s):  
Rock Mass ◽  
Elastic Strain ◽  
Strain Energy ◽  
Elastic Strain Energy ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Joint Density ◽  
Dissipated Energy ◽  
Uniaxial Compression Test ◽  
Plastic Rock

The prediction of rockburst proneness is the basis of preventing and controlling rockburst disasters in rock engineering. Based on energy theory and damage mechanics, the quantitative functional relationship between joint density and energy density was derived. Then, the theoretical results were verified by numerical simulation and uniaxial compression test, and the effect of joint density on rockburst proneness of the elastic-brittle-plastic rock mass was discussed. The results show that the relationship between the joint density and the dissipated energy index of the jointed rock mass is a logarithmic function. With the same total input energy, the higher the joint density, the more the damage dissipation energy. Even in the case of high joint density, the rock mass still has limited resistance to external failure. Under the same joint density, the strength of parallel jointed rock mass is better than that of the cross-jointed rock mass, and the parallel jointed rock mass can accumulate more elastic strain energy and has higher rockburst proneness. The joint density is closely related to the ability of the rock mass to store high strain energy. The higher the joint density is, the weaker the ability to accumulate the elastic strain energy of rock mass is and the lower the rockburst proneness is. It is helpful to predict rockburst proneness by investigating and studying the properties of geological discontinuities. The research results have some theoretical and engineering guiding significance for the prediction of rockburst proneness of the jointed rock mass.

scholarly journals Dynamic Stability Critical State of Pin-Ended Arches under Sudden Central Concentrated Load

Mechanika ◽  
2020 ◽  
Vol 26 (5) ◽  
Author(s):  
Kai QIN ◽  
Jingyuan LI ◽  
Mengsha LIU ◽  
Jinsan JU
Keyword(s):  
Finite Element ◽  
Critical Load ◽  
Critical State ◽  
Elastic Strain ◽  
Strain Energy ◽  
Elastic Strain Energy ◽  
The State ◽  
Energy Principle ◽  
Concentrated Load ◽  
Elastic Plastic

The dynamic in-plane instability process of extreme point type for pin-ended arches when a central radial load applied suddenly with infinite duration is analyzed with finite element method in this study. The state of arch can be determined by the crown’s vertical displacement varied with time and the critical load can be obtained by repeating trial-calculation. When the arch structure reaches the dynamically stable critical state, the kinetic energy of the structure is very small or even zero. The dynamic critical load of elastic arch calculated with the theoretical analysis method which is based on energy principle is proved accuracy enough by comparing with the finite element calculation results and the percentage of the differences between them are no more than 4.5 %. The maximal elastic strain energy is certain for the elastic-plastic arch in certain geometry under both a sudden load and static load. The maximal elastic strain energy in static calculation can be used in determining the state of the elastic-plastic arch under dynamic sudden loads applied and this method is more accurate which errors won’t exceed 3.5 %. The accuracy of dynamic critical load calculation method for elastic arch is verified by numerical calculation in this study, and based on the characteristic of elastic strain energy in critical state, a method for determining the stability of elastic-plastic arch is presented.

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