Three-Dimensional Wave Propagation in a Cracked Elastic Solid

1978 ◽  
Vol 45 (4) ◽  
pp. 807-811 ◽  
Author(s):  
S. Itou

The three-dimensional dynamic problem is presented for an infinite elastic medium weakened by a plane crack of infinite length and finite width. On the surfaces of the crack, the self-equilibrated system of a load varies harmonically in time and is distributed arbitrarily on those surfaces. The Fourier transformations are utilized to reduce the problem to a solution of two simultaneous integral equations which can be solved by using the series expansion method. The dynamic stress-intensity factor is computed numerically for some applied loads.

1981 ◽  
Vol 4 (1) ◽  
pp. 165-180 ◽  
Author(s):  
S. Itou

The problem of a uniformly propagating finite crack in an infinite medium is solved within the linearized couple-stress theory. The self-equilibrated system of pressure is applied to the crack surfaces. The problem is reduced to dual integral equations and solved by a series-expansion method. The dynamic stress-intensity factor is computed numerically.


2013 ◽  
Vol 05 (04) ◽  
pp. 1350044
Author(s):  
XIANHONG MENG ◽  
ZHAOYU BAI ◽  
MING LI

In this paper, the three-dimensional dynamic problem for an infinite elastic medium weakened by a crack of infinite length and finite width is analyzed, while the crack surfaces are subjected to mode I transient linear tractions. The integral transform approach is applied to reduce the governing differential equations to a pair of coupled singular integral equations, whose solutions can be obtained with the typical iteration method. The analytical solution of the stress intensity factor when the first wave and the first scattered wave reach the investigated crack tip is obtained. Numerical results are presented for different values of the width-to-longitudinal distance ratio z/l. It is found that the stress intensity factor decreases with the arrival of the first scattered longitudinal wave and increases with the arrival of the first scattered Rayleigh wave and tends to be stable. The static value considering both the first scattered wave and the first wave is about 50% greater than that considering only the first wave, and then the effect of the reflected wave is remarkable and deserves further study.


1972 ◽  
Vol 39 (4) ◽  
pp. 1027-1032 ◽  
Author(s):  
L. B. Freund

Wave propagation in an isotropic elastic solid containing a slit is studied. The slit is viewed as an open crack of finite width and infinite length. In particular, the propagation of surface waves on the faces of the slit is considered. Making use of a reflection law for the oblique reflection of a Rayleigh wave from the tip of an open half-plane crack, surface waves are superimposed to form guided surface waves in the slit. In order to carry out the construction of dispersion relations, an assumption on the rate of decay of body wave modes localized in the vicinity of the edges of the guide is made, and the range of validity of the assumption is discussed. The dispersion relations are obtained by geometrical construction, and representative dispersion curves are shown.


1998 ◽  
Vol 120 (1) ◽  
pp. 194-198 ◽  
Author(s):  
Chang-Qing Chen ◽  
Ya-Peng Shen

An exact elasticity study of the free vibration of a simply-supported cross-ply cylindrical shell containing a piezoelectric layer is presented. The solution of the derived governing differential equations is obtained through the power series expansion method. Both the direct and inverse piezoelectric effects are investigated. Results presented here provide an understand of the behavior of piezoelectric materials when acted as smart materials and can be used to assess various numerical results obtained from approximate shell theories.


2011 ◽  
Vol 312-315 ◽  
pp. 959-964
Author(s):  
Oronzio Manca ◽  
Sergio Nardini ◽  
Daniele Ricci ◽  
Salvatore Tamburrino

This work presents a three-dimensional heat transfer model developed for laser material processing with a moving Gaussian and donut heat sources, using Comsol Multhiphysics 3.5 code. The laser beam, having a defined power distribution, strikes the surface of an opaque substrate of semi infinite length but finite width and depth moving with a uniform velocity in the positive axial direction. The solid dimension along the motion direction is assumed to be infinite or semi-infinite, while a finite width and thickness are considered. Thermal properties are considered temperature dependent. Surface heat losses toward the ambient are taken into account. The results are presented in terms of temperature profiles and thermal fields are given for some Biot and material thicknesses at a constant Peclet number.


1988 ◽  
Vol 110 (2) ◽  
pp. 181-186 ◽  
Author(s):  
Zhengming Wang

A special inverse problem is formulated in which the shape of the mean streamline and the circumferential thickness distribution of the profile are given. On the basis of the series expansion method on a selected streamline, in quasi-three-dimensional aerodynamic design, the blade profile thickness is automatically fulfilled by computer. Six radial sections of a turbine blade are designed by this method.


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