A Note on Elastic Surface Deformation

1951 ◽  
Vol 18 (3) ◽  
pp. 251-252
Author(s):  
Murray Kornhauser
Keyword(s):  
Principal Curvature ◽  
Surface Deformation ◽  
The Other ◽  
Elastic Surface ◽  
Elastic Bodies

Abstract Surface deformation of elastic bodies having the same modulus is treated by the standard texts on elasticity, but the applicability of the solution is limited to the range of the tables of coefficients presented. This note extends the tables to cover the range that applies to bodies having one principal curvature much larger than the other. Some inaccuracy in the tables in current use also is noted. The reader is referred to any good text on elasticity for a general discussion of this problem.

scholarly journals Elastic and non-elastic surface deformation in New Zealand

1970 ◽  
Vol 3 (4) ◽  
pp. 131-142
Author(s):  
G. J. Lensen
Keyword(s):  
New Zealand ◽  
Surface Deformation ◽  
Elastic Surface

Over the last decade it has become evident that not all surface deformation takes place during earthquakes. Deformation associated with earthquakes and their aftershocks appears to be non-elastic in nature, while in between earthquakes deformation appears to be elastic.

The Contact Problem Studied by Pseudocaustics Formed at the Vicinity of the Contact Zone

1984 ◽  
Vol 106 (3) ◽  
pp. 211-215 ◽  
Author(s):  
P. S. Theocaris ◽  
C. A. Stassinakis
Keyword(s):  
Contact Problem ◽  
Contact Zone ◽  
Contact Area ◽  
The Other ◽  
Tangential Stresses ◽  
Elastic Bodies ◽  
First Case ◽  
Reflected Light ◽  
Spline Polynomial ◽  
Distribution Of Stresses

The method of caustics is applied to formulate the normal and tangential stresses developed in the contact zone of two elastic bodies, and also for one elastic and the other plastic. The stresses are represented by a cubic spline polynomial, its coefficients calculated by pseudocaustics from reflected light around the contact zone. The method is applied to determine the stresses along the boundary of a half-plane and the stresses along the contact area of two disks. The deviation of calculated stresses from the applied ones, in the first case was small, while in the second case it was found that the normal distribution of stresses was similar to a Hertzian distribution. This experimental method can be used to accurately obtain contact stresses.

scholarly journals On the expediency of assigning specific names to such functions of simple elements as represent definite physical properties; with the suggestion of a new term in mechanics; illustrated by an investigation of the machine moved by recoil, and also by some observations on the steam engine

1833 ◽  
Vol 2 ◽  
pp. 299-300
Keyword(s):  
Physical Properties ◽  
Effective Action ◽  
The Other ◽  
Steam Engine ◽  
Similar Function ◽  
Centre Of Gravity ◽  
Elastic Bodies ◽  
General Law ◽  
The Subject ◽  
The Common

The author commences this paper by stating the necessity of distinguishing by separate appellations all such functions as measure the intensity of physical properties, which he considers rendered obvious by a reference to the controversy respecting motion. The subject of this controversy, he observes, was the measure of motion itself, it being contended on one hand that the motion of a body is always proportional to its weight multiplied by its velocity; this opinion being supported by reference to the properties of the common centre of gravity of systems, &c.; while on the other hand the affections of elastic bodies in collision, and the general law of the conservation of living or active forces, were adduced in support of the latter measure. No sooner, however, were the terms “momentum” and “impetus” introduced into the science of mechanics, than the opinions of the contending parties were reconciled by the removal of every ground of dispute. In the Bakerian lecture on the force of percussion, read to this Society in 1806, he observes, it is remarked, that neither impetus nor momentum are usually correct measures of the effective action of machines. The criterion of this is the force exerted, multiplied by the space through which it acts, and this measure numerically expressed has been denominated duty by Mr. Watt; and the raising of one pound one foot high has been by him made the dynamic unit; according to which estimate, the duty performed by one bushel of coals, of 84 pounds, has been found to vary from 30 to 50 millions of such units, according to the nature of the engine, and the mode of combustion. To the measure or function represented by the force applied, multiplied by the space through which it acts, the author, however, proposes to give the name efficiency, retaining the word duty for a similar function, indicative of the work performed; and by a comparison of these two functions, viz. the efficiency expended on, and the duty performed by, any machine, an exact measure of its intrinsic work will be obtained.

Pneumatically Driven Multi-DOF Surgical Forceps Manipulator with a Bending Joint Mechanism Using Elastic Bodies

2016 ◽  
Vol 28 (4) ◽  
pp. 559-567 ◽  
Author(s):  
Kyouhei Takikawa ◽  
◽  
Ryoken Miyazaki ◽  
Takahiro Kanno ◽  
Gen Endo ◽  
...  
Keyword(s):  
The Other ◽  
Tracking Performance ◽  
Slave System ◽  
Flexible Joints ◽  
Drive Unit ◽  
Bending Angle ◽  
Bending Force ◽  
Elastic Bodies ◽  
Joint Mechanism ◽  
Pneumatic Cylinders

[abstFig src='/00280004/13.jpg' width='300' text='Proposed pneumatically driven multi-DOF surgical forceps manipulator' ] In this study, a pneumatically-driven forceps manipulator was developed for a master-slave-type surgical robot. The proposed manipulator had two flexible joints, one for the bending joint at the tip and the other for transmitting a bending force from the actuators to the wires of the forceps. The manipulator had two degree-of-freedoms (DOFs) of bending driven by only two pneumatic cylinders and a gripper driven by a cylinder. Given the interoperability in real surgery, a mechanism was proposed such that the clean forceps part could be easily attached to and detached from the filthy drive unit. An experiment of the master-slave-system was conducted with the proposed manipulator to verify the tracking performance of the cylinders’ position and the bending angle of the forceps manipulator.

Contact Between Elastic Bodies With an Elliptic Contact Interface in Torsion

1997 ◽  
Vol 64 (1) ◽  
pp. 144-148 ◽  
Author(s):  
J. F. Cuttino ◽  
T. A. Dow
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
The Other ◽  
Contact Interface ◽  
Element Analysis ◽  
Elastic Bodies ◽  
Torque Generation ◽  
Elliptical Contact ◽  
Elliptic Contact

When two elastic three-dimensional bodies of specified radii come into contact, Hertzian forces at the interface result in the formation of an elliptical contact area. The rotation of one body relative to the other about an axis normal to the contact induces a nonlinear torque due to the progression of sliding in the contact interface. Using finite element analysis, a relationship describing torsional compliance with slip is presented for two elastic bodies with an elliptic contact interface under pure twist. The effect of changing material and geometric parameters is studied, and the relationships between torque generation and angle are defined with respect to these nondimensionalized parameters.

Effect of elastic surface deformation on the relation between hardness and yield strength

2004 ◽  
Vol 19 (12) ◽  
pp. 3704-3714 ◽  
Author(s):  
L.J. Vandeperre ◽  
F. Giuliani ◽  
W.J. Clegg
Keyword(s):  
Yield Strength ◽  
Analytical Approach ◽  
Surface Deformation ◽  
High Ratio ◽  
Elastic Surface ◽  
Hard Materials ◽  
Surface Deflection ◽  
The Relationship ◽  
Indenter Shape ◽  
Measured Hardness

The use of an analytical approach to determine the relation between hardness and yield strength for materials with a high ratio of yield strength to Young's modulus is re-examined. It is shown that predictions using the analogy of the spherical cavity fail to reproduce experimental and finite element results because the surface deflection that occurs during loading is not taken into account. A modification is proposed to allow this. This gives a greatly improved prediction of the relationship between the hardness and yield strength of a material. It also enables the effect of the indenter shape on the measured hardness to be incorporated and explains why in some very hard materials, indentation is observed to be completely elastic.

scholarly journals The role of boundary conditions on the dynamics of green coffee beans in a rotated dryer

2018 ◽  
Author(s):  
Marcos A.S. Barrozo ◽  
M.V.C. Machado ◽  
I.A. Resende ◽  
R.M. Lima ◽  
R.J. Brandão ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Surface Deformation ◽  
The Other ◽  
Green Coffee Beans ◽  
Rotary Dryer ◽  
Coffee Beans ◽  
Euler Model ◽  
Great Relevance

Coffee drying and roasting are usually performed in rotated dryers; therefore, the study of particle dynamics in this equipment is of great relevance to improve their efficiency and hence the quality of the final product. Thus, this work aimed to investigate experimentally and numerically the dynamics of coffee beans in a rotary dryer. The Euler-Euler model was employed to reproduce the particle velocity profile in the rolling regime under different boundary conditions. The results shown that the lower specularity coefficient (0.01), which characterizes the smooth wall and free slip condition, reproduced the bed behavior that most resembled the experimental one. On the other hand, the other coefficients (0.1 and 1.0) showed an increasing deformation in the bed surface, different from the observed experimental behavior. It was also verified that, as the filling degree increases, the bed surface deformation becomes more pronounced. Keywords: coffee; rotated dryer; simulation; specularity coefficient.  

Thermal Weight Functions and Stress Intensity Factors for Bonded Dissimilar Media Using Body Analogy

2011 ◽  
Vol 78 (6) ◽  
Author(s):  
Ratnesh Khandelwal ◽  
J. M. Chandra Kishen
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
The Other ◽  
Weight Functions ◽  
Two Dimensional ◽  
Intensity Factors ◽  
Analogy Method ◽  
Elastic Bodies ◽  
Crack Problems ◽  
Finite Crack

In this study, an analytical method is presented for the computation of thermal weight functions in two dimensional bi-material elastic bodies containing a crack at the interface and subjected to thermal loads using body analogy method. The thermal weight functions are derived for two problems of infinite bonded dissimilar media, one with a semi-infinite crack and the other with a finite crack along the interface. The derived thermal weight functions are shown to reduce to the already known expressions of thermal weight functions available in the literature for the respective homogeneous elastic body. Using these thermal weight functions, the stress intensity factors are computed for the above interface crack problems when subjected to an instantaneous heat source.

scholarly journals Deformation induced topographic effects in inversion of temporal gravity changes: First look at Free Air and Bouguer terms

2015 ◽  
Vol 45 (2) ◽  
pp. 149-171 ◽  
Author(s):  
Peter Vajda ◽  
Pavol Zahorec Pavol ◽  
Juraj Papčo ◽  
Anna Kubová
Keyword(s):  
Surface Deformation ◽  
Vertical Gradient ◽  
Spatial Behavior ◽  
The Other ◽  
Volcanic Complex ◽  
Topographic Effects ◽  
Deformation Effect ◽  
Gravity Station ◽  
Gravity Changes ◽  
Free Air

Abstract We review here the gravitational effects on the temporal (time-lapse) gravity changes induced by the surface deformation (vertical displacements). We focus on two terms, one induced by the displacement of the benchmark (gravity station) in the ambient gravity field, and the other imposed by the attraction of the masses within the topographic deformation rind. The first term, coined often the Free Air Effect (FAE), is the product of the vertical gradient of gravity (VGG) and the vertical displacement of the benchmark. We examine the use of the vertical gradient of normal gravity, typically called the theoretical or normal Free Air Gradient (normal FAG), as a replacement for the true VGG in the FAE, as well as the contribution of the topography to the VGG. We compute a topographic correction to the normal FAG, to offer a better approximation of the VGG, and evaluate its size and shape (spatial behavior) for a volcanic study area selected as the Central Volcanic Complex (CVC) on Tenerife, where this correction reaches 77% of the normal FAG and varies rapidly with terrain. The second term, imposed by the attraction of the vertically displaced topo-masses, referred to here as the Topographic Deformation Effect (TDE) must be computed by numerical evaluation of the Newton volumetric integral. As the effect wanes off quickly with distance, a high resolution DEM is required for its evaluation. In practice this effect is often approximated by the planar or spherical Bouguer deformation effect (BDE). By a synthetic simulation at the CVC of Tenerife we show the difference between the rigorously evaluated TDE and its approximation by the planar BDE. The complete effect, coined here the Deformation Induced Topographic Effect (DITE) is the sum of FAE and TDE. Next we compare by means of synthetic simulations the DITE with two approximations of DITE typically used in practice: one amounting only to the first term in which the VGG is approximated by normal FAG, the other adopting a Bouguer corrected normal FAG (BCFAG).

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