A Cracked Surface Layer Bonded to a Cracked Half Space

Author(s):  
M. Rusen Gecit
Keyword(s):  
2012 ◽  
Vol 560-561 ◽  
pp. 338-343 ◽  
Author(s):  
Nikolay A. Voronin

The mechanics of contact interaction of rigid spherical indenter with two-layer elastic - plastic half-space, simulating a surface of a solid body with a thin surface layer is considered. Analytical dependences of critical indentation and bearing capacity on mechanical characteristics of materials of a base and a coating, and as well as that for thickness of top layer (coating) in all region of possible thickness are received and analyzed. Existence of regions of the abnormal structural strength allowing the surface layered material to identify unequivocally as a topocomposite is shown. Theoretical dependences were verified by a final elements method.


Geophysics ◽  
1959 ◽  
Vol 24 (1) ◽  
pp. 12-29 ◽  
Author(s):  
James Dorman

The IBM 650 computer of the Watson Scientific Computing Laboratory, Columbia University, was programmed to obtain numerical solutions for the period equation for Love waves on a half‐space with a double surface layer. Solutions including higher modes for seven models of the continental crust‐mantle system are presented. This group of related cases shows that certain properties of the solutions are diagnostic of crustal structure. These relationships are illustrated graphically.


1994 ◽  
Vol 60 (575) ◽  
pp. 1572-1578
Author(s):  
Toshikazu Shibuya ◽  
Hirotsugu Inoue ◽  
Masaki Kawamura ◽  
Kikuo Kishimoto

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Sergey V. Kuznetsov ◽  
Aybek E. Nafasov

The basic idea of a seismic barrier is to protect an area occupied by a building or a group of buildings from seismic waves. Depending on nature of seismic waves that are most probable in a specific region, different kinds of seismic barriers can be suggested. Herein, we consider a kind of a seismic barrier that represents a relatively thin surface layer that prevents surface seismic waves from propagating. The ideas for these barriers are based on one Chadwick's result concerning nonpropagation condition for Rayleigh waves in a clamped half-space, and Love's theorem that describes condition of nonexistence for Love waves. The numerical simulations reveal that to be effective the length of the horizontal barriers should be comparable to the typical wavelength.


Author(s):  
Ali Yu. Albagachiev ◽  
◽  
A.M. Moiseenko ◽  
E.V. Zernov ◽  
A.V. Lut’yanov ◽  
...  

The problem of the indenter embedding into a half-space is formulated and solved. A concept of the elastic contact is used, which implies the uniformity of the stress-strain state in a surface layer. The process of the surface layer formation after mechanical treatment is studied. Based on the general theory of indenter penetration into a half-space, numerical and analytical solutions, determining the length and depth of penetration of a paraboloid into elastoplastic space, are obtained. According to the theory of indentation, the problem is reduced to the use of the method of approximate determination of geometric parameters of a bead, when a paraboloid is being embedded into elastoplastic space. An exact solution to the formulated problem allows one to obtain analytical dependences for calculating the velocities and to study the stress-strain state of the material in the half-space surface layer during the processing. The reliability of the obtained analytical solution is confirmed by numerical calculations without introducing additional hypotheses. Based on the analytical solution, the geometric parameters of the influx from the penetration depth are determined. Calculations can be performed at any embedding depth. Sag formation during the indenter embedding by 18 mm into plasticine specimens is considered as an example. It is shown that the rigid zone is insignificant or absent.


Geophysics ◽  
1983 ◽  
Vol 48 (11) ◽  
pp. 1453-1467
Author(s):  
Geoffrey A. Dorn

The thickness and shear‐wave velocity of a surface layer can theoretically be determined from seismic radiation impedance measurements using a torsional vibrator. These studies also provide physical insight into vibrator‐earth interaction. The radiation impedance of a circular disk vibrating torsionally on an anelastic half‐space has resonance peaks with a spacing that is a function of the ratio between baseplate radius and seismic wavelength. At low frequencies the shape of the impedance function is nearly independent of the baseplate flexure, although the magnitude is affected. At high frequencies the impedance depends strongly on the flexibility of the baseplate. The mass of the baseplate introduces an additional resonant effect, the frequency of which is a function of the baseplate mass. The presence of a surface layer produces an impedance curve which oscillates around the half‐space response. The amplitude of the oscillations is a function of the acoustic impedance contrast and depends upon the radiation pattern of the source. The oscillations are resonances caused by reflections within the surface layer, and both the period and amplitude of the oscillations are inversely proportional to the layer thickness. The amplitude of the layer resonance decreases rapidly as material damping increases. With impedance measurements over a sufficiently broad frequency range (up to about 500 Hz), it may be feasible to use half‐space oscillations and the layer resonances to determine the shear velocity and thickness of the layer of material beneath the baseplate.


Wave Motion ◽  
2015 ◽  
Vol 56 ◽  
pp. 205-220 ◽  
Author(s):  
Priza Kayestha ◽  
Elizabete Rodrigues Ferreira ◽  
Anil C. Wijeyewickrema

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