Dynamic Stresses Around Elliptical Discontinuities

1972 ◽  
Vol 39 (1) ◽  
pp. 133-138 ◽  
Author(s):  
K. R. Schroll ◽  
S. L. Cheng
Keyword(s):  
Maximum Stress ◽  
Dynamic Stress ◽  
Wave Number ◽  
Stress Concentrations ◽  
Dynamic Stresses ◽  
Source Distance ◽  
Unbounded Elastic Medium ◽  
P And Sv Waves ◽  
Maximum Stresses ◽  
Dynamic Stress Concentrations

The influence of an elliptical discontinuity on the stress distribution in an otherwise uninterrupted and unbounded elastic medium subjected to the passage of both P- and SV-waves is examined. The elliptical scatterer is either empty or filled with a rigid and infinitely dense material. Ratios of the maximum stresses on the elliptical scatterer boundary to the maximum stress of the incident wave are computed to demonstrate the effect of dynamic stress concentrations. Results are presented which show the influence on the stresses of the ellipse eccentricity, the normalized wave number as well as the ratio of nondimensional source distance to wavelength.

Diffractions of Horizontal Shear Waves by a Parabolic Cylinder and Dynamic Stress Concentrations

1966 ◽  
Vol 33 (4) ◽  
pp. 785-792 ◽  
Author(s):  
S. A. Thau ◽  
Yih-Hsing Pao
Keyword(s):  
Dynamic Stress ◽  
Shear Waves ◽  
Wave Number ◽  
Parabolic Cylinder ◽  
Horizontal Shear ◽  
Stress Concentrations ◽  
Infinite Line ◽  
Rigid Ribbon ◽  
Line Crack ◽  
Dynamic Stress Concentrations

Diffractions of horizontally polarized shear waves by a parabolic cylinder are studied by using the expansion of solutions to the wave equation in terms of Weber’s functions. The parabolic cylinder is either empty or filled with rigid material. Also, the problems of a semi-infinite line crack and a semi-infinite rigid ribbon as two limiting cases are treated. Displacements and stresses are calculated near the base of the parabola. In the case of a line crack or a rigid ribbon, the singular behavior of stresses is shown to be of the order of (kr)−1/2, where k is the wave number and r the distance from the tip.

A Finite Element Approach to Dynamic Stresses of Helical Gear Pairs Considering Tip Relief and Crowning Modifications

2013 ◽  
Vol 284-287 ◽  
pp. 577-581
Author(s):  
Kuo Jao Huang ◽  
Ching Ya Su
Keyword(s):  
Finite Element ◽  
Dynamic Stress ◽  
Helical Gear ◽  
Dynamic Responses ◽  
High Quality ◽  
Dynamic Stresses ◽  
Dynamic Finite Element ◽  
Bending Stresses ◽  
Element Approach ◽  
Maximum Stresses

A dynamic finite element (FE) approach to contact and fillet bending stresses of helical gear pairs (HGPs) is presented. Using derived tooth profiles, high quality elements of HGPs can be efficiently constructed. The resulted maximum stresses of elements on teeth are 3D illustrated. Design of relief and profile modifications is also condisered. The effect of tooth modifications on HGP dynamic responses including misalignment errors is discussed. It shows adequate modification of tip relief and crowning can reduce dynamic stress peaks of HGPs.

Dynamic Stresses Concentrations of SH Wave by Circular Tunnel with Lining

2011 ◽  
Vol 323 ◽  
pp. 18-22 ◽  
Author(s):  
Yi Guang Zhang ◽  
Chuan Lu Zhou ◽  
Yi Xian Liu
Keyword(s):  
Stress Concentration ◽  
Dynamic Stress ◽  
Wave Number ◽  
Dynamic Stress Concentration ◽  
Sh Wave ◽  
Circular Tunnel ◽  
Dynamic Stresses ◽  
Shear Elasticity ◽  
Concentration Factors ◽  
Stress Concentration Factors

Based on the scattering theory of elastic waves, employing the wave function expansion method, the scattering and the dynamic stresses concentration of SH wave by circular tunnel with lining are investigated. The analytical solution of the problem is derived, and the numerical solution of the dynamic stress concentration factors around the lining is presented. The effects of the shear elasticity of the surrounding rock and the lining, the wave number on the dynamic stress concentration factors are analyzed. Analysis has shown that the shear elasticity of the surrounding rock and the wave number are factors that influence dynamic stress concentration factor, and provide important theoretical foundation for the earthquake evaluation of lining.

Diffraction of Plane Compressional Waves by an Array of Nanosized Cylindrical Holes

2010 ◽  
Vol 78 (2) ◽  
Author(s):  
Q. F. Zhang ◽  
G. F. Wang ◽  
P. Schiavone
Keyword(s):  
Surface Energy ◽  
Dynamic Stress ◽  
Surface Elasticity ◽  
Expansion Method ◽  
Stress Concentrations ◽  
Compressional Waves ◽  
Circular Holes ◽  
Cylindrical Holes ◽  
Effect Of Surface ◽  
Dynamic Stress Concentrations

When the radius of a hole reduces to nanometers, the influence of surface energy becomes prominent in its mechanical behavior. In the present paper, we consider the diffraction of plane compressional waves by an array of nanosized circular holes in an elastic medium. The effect of surface energy is taken into account through surface elasticity theory. Using the wave expansion method, we derive the corresponding elastic diffraction fields. Dynamic stress concentrations around the holes and the scattering cross section are calculated to address the surface effects on the diffraction phenomena.

Supports’ Dynamical Optimized Design for the External Pipeline of Aircraft Engine

2010 ◽  
Vol 139-141 ◽  
pp. 2456-2459 ◽  
Author(s):  
Hong Bo Zhai ◽  
Bao Hui Li ◽  
Zhi Feng Jiang ◽  
Zhu Feng Yue
Keyword(s):  
Dynamic Stress ◽  
Aircraft Engine ◽  
Random Excitation ◽  
Optimized Design ◽  
Three Dimension ◽  
Vibration Level ◽  
Dynamic Stresses ◽  
Fracture Failure ◽  
The Relationship ◽  
Maximum Stresses

A three dimension model of some aircraft engine’s pipeline has been established to study dynamic characteristics of the pipeline under random excitation. The relationship between the supports’ parameters and the dynamic characters of the pipeline was also presented. In order to avoid the harmful resonance, depress the vibration level and reduce the dynamic stresses of the pipeline, a specific dynamical optimized method was proposed and the supports’ layout and parameters (location, quantity) were analyzed and optimized. The results show that 1) Under random excitation, the maximum stresses are located near the bushing with serious stress concentration and the ends of pipeline. Fracture failure easily occurs in these parts. 2) The supports’ optimized method of the pipeline proposed in this paper is reasonable and effective. And the optimized pipeline has less dynamic stress and better anti-vibration capability.

Dynamic Stress Concentrations at Circular Holes in Struts

1965 ◽  
Vol 7 (1) ◽  
pp. 23-27 ◽  
Author(s):  
J. W. Dally ◽  
W. F. Halbleib
Keyword(s):  
Fringe Pattern ◽  
Dynamic Stress ◽  
Static Stress ◽  
Stress Concentrations ◽  
Circular Holes ◽  
The Difference ◽  
Dynamic Stress Concentrations

Dynamic stress concentrations were determined for a strut with a centrally located hole by employing photoelastic measurements. Single spark photography together with controlled repeated loadings on Columbia resin CR-39 models was utilized to obtain the dynamic fringe pattern. In general, it was found that the dynamic stress concentrations differed significantly from the static stress concentrations. The difference depended upon the geometry of the model and the location at the boundary of the hole.

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