Development and application of three-dimensional light distribution model for laser irradiated tissue

1987 ◽  
Vol 23 (10) ◽  
pp. 1721-1733 ◽  
Author(s):  
G. Yoon ◽  
A. Welch ◽  
M. Motamedi ◽  
M.v. Gemert
Keyword(s):  
Three Dimensional ◽  
Light Distribution ◽  
Distribution Model

Simulation of Three-Dimensional Stress Distribution in Compression Dies

2008 ◽  
Vol 575-578 ◽  
pp. 449-454
Author(s):  
Chu Yun Huang ◽  
Sai Yu Wang ◽  
Tao Yang ◽  
Xu Dong Yan
Keyword(s):  
Stress Distribution ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Distribution Model ◽  
Extrusion Dies ◽  
Maximum Value ◽  
Multiple Unit ◽  
Stress Freezing Method ◽  
Experimental Values ◽  
Aided Design

The stress fields of rectangular and T shape compression dies were simulated by three dimensional photo-elasticity of stress freezing method. The rules of stress distribution of σx, σy, σz on the surface of rectangular and T-shaped dies were discovered, and the rules were also found inside the dies. The results indicate that the stress distribution of rectangular die is similar to that of T shape die. Obvious stress concentration in corner of die hole was observed. σz rises from die hole to periphery until it achieves maximum value then it diminishes gradually, and σz between die hole and fix diameter zone is higher than it is in other position. At the same time, the equations of stress field of extrusion dies were obtained by curved surface fitting experimental values in every observed point with multiple-unit regression analysis method and orthogonal transforms. These works can provide stress distribution model for die computer aided design and make.

A Three-Dimensional Load Sharing Model of Planetary Gear Sets Having Manufacturing Errors

2015 ◽  
Author(s):  
Nicholas D. Leque ◽  
Ahmet Kahraman
Keyword(s):  
Three Dimensional ◽  
Planetary Gear ◽  
Load Sharing ◽  
Distribution Model ◽  
Gear Mesh ◽  
Position Errors ◽  
Proposed Model ◽  
Manufacturing Errors ◽  
Manufacturing Tolerancing ◽  
Planetary Gear Sets

Planet-to-planet load sharing is a major design and manufacturing tolerancing issue in planetary gear sets. Planetary gear sets are advantageous over their countershaft alternatives in many aspects, provided that each planet branch carries a reasonable, preferably equal, share of the torque transmitted. In practice, the load shared among the planets is typically not equal due to the presence of various manufacturing errors. This study aims at enhancing the models for planet load sharing through a three-dimensional formulation of N-planet helical planetary gear sets. Apart from previous models, the proposed model employs a gear mesh load distribution model to capture load and time dependency of the gear meshes iteratively. It includes all three types of manufacturing errors, namely constant errors such as planet pinhole position errors and pinhole diameter errors, constant but assembly dependent errors such as nominal planet tooth thickness errors, planet bore diameter errors, and rotation and assembly dependent errors such as gear eccentricities and run-outs. At the end, the model is used to show combined influence of these errors on planet load sharing to aid designers on how to account for manufacturing tolerances in the design of the gears of a planetary gear set.

Differentiation of Gliomas Using Tissue Parameters and a Three-dimensional Density Distribution Model

1990 ◽  
pp. 294-298
Author(s):  
P. Pedrosa ◽  
M. Jungke ◽  
M. Grigat ◽  
H. P. Higer ◽  
S. Meindl ◽  
...  
Keyword(s):  
Density Distribution ◽  
Three Dimensional ◽  
Distribution Model

scholarly journals A Semi-Analytical Load Distribution Model for Cycloid Drives with Tooth Profile and Longitudinal Modifications

2020 ◽  
Vol 10 (14) ◽  
pp. 4859
Author(s):  
Ting Zhang ◽  
Xuan Li ◽  
Yawen Wang ◽  
Lining Sun
Keyword(s):  
Load Distribution ◽  
Contact Stiffness ◽  
Three Dimensional ◽  
Elastic Half Space ◽  
Distribution Model ◽  
Influence Coefficient ◽  
Hertz Contact ◽  
Tooth Contact Analysis ◽  
Tooth Contact ◽  
Analysis And Design

The current load distribution model for cycloid drives based on the Hertz contact stiffness typically assumes a two-dimensional planar problem without considering the tooth longitudinal modification effects, which fails to comply with the practical situation. In this paper, this issue is clarified by developing a semi-analytical load distribution model based on a three-dimensional and linear elastic solution. Unloaded tooth contact analysis is introduced to determine the instantaneous mesh information. The tooth compliance model considering tooth contact deformation is established by combining the Boussinesq force–displacement relationships in elastic half-space with an influence coefficient method. With this, the loads, contact patterns, and loaded transmission error are calculated by enforcing the compatibility and equilibrium conditions. Comparisons to predictions made with the assumption of Hertz contact stiffness are presented to demonstrate the effectiveness of the proposed model, which shows good agreement. At the end, the effect of tooth longitudinal modifications on load distributions is investigated along with various loading conditions. This study yields an in-depth understanding of the multi-tooth contact characteristics of cycloid drives and provides an effective tool for extensive parameter sensitivity analysis and design optimization studies.

scholarly journals Deprojection of Galaxies: How Much Can Be Learned?

1987 ◽  
Vol 127 ◽  
pp. 397-398 ◽  
Author(s):  
George B. Rybicki
Keyword(s):  
Symmetry Axis ◽  
Three Dimensional ◽  
Light Distribution ◽  
Axially Symmetric ◽  
Simple Criterion ◽  
Slice Theorem ◽  
Intrinsic Shape ◽  
Model Independent ◽  
Fourier Slice Theorem

A general discussion, based on the ht “Fourier Slice Theorem,” is given for the problem of deprojecting the observed light distribution of galaxies to obtain their intrinsic three dimensional light distribution or “shape.” Several results are obtained: 1) A model-independent deprojection of an axially symmetric galaxy is shown to be possible only if the symmetry axis lies in the plane of the sky. 2) A simple criterion is given to test whether two different galaxies can have the same intrinsic shape, based solely on their observed projections. 3) It is shown that a homogeneous class of galaxies can be deprojected using a sufficiently large number of projections of random perspective.

scholarly journals SCARE: A Postprocessor Program to MSC/NASTRAN for Reliability Analysis of Structural Ceramic Components

1986 ◽  
Vol 108 (3) ◽  
pp. 540-546 ◽  
Author(s):  
J. P. Gyekenyesi
Keyword(s):  
Least Squares Method ◽  
Three Dimensional ◽  
Strain Energy Release ◽  
Maximum Tensile Stress ◽  
Strength Distribution ◽  
Modulus Of Rupture ◽  
Distribution Model ◽  
Mixed Mode Fracture ◽  
Ceramic Components ◽  
Fast Fracture

A computer program is developed for calculating the statistical fast fracture reliability and failure probability of ceramic components. The program includes the two-parameter Weibull material fracture strength distribution model, using the principle of independent action for polyaxial stress states and Batdorf’s shear-sensitive as well as shear-insensitive crack theories, all for volume distributed flaws in macroscopically isotropic solids. Both penny-shaped cracks and Griffith cracks are included in the Batdorf shear-sensitive crack response calculations, using Griffith’s maximum tensile stress or critical coplanar strain energy release rate criteria to predict mixed mode fracture. Weibull material parameters can also be calculated from modulus of rupture bar tests, using the least-squares method with known specimen geometry and fracture data. The reliability prediction analysis uses MSC/NASTRAN stress, temperature, and volume output, obtained from the use of three-dimensional, quadratic, isoparametric, or axisymmetric finite elements. The statistical fast fracture theories employed, along with selected input and output formats and options, are summarized. A sample problem to demonstrate various features of the program is included.

STRUCTURE SIMULATIONS OF LIQUID S AND LIQUID Te BY UNCONSTRAINED REVERSE MONTE CARLO METHOD

1996 ◽  
Vol 10 (25) ◽  
pp. 1267-1276 ◽  
Author(s):  
M. ANDRECUT
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Three Dimensional ◽  
Distribution Model ◽  
Dimensional Structure ◽  
Angle Distribution ◽  
Structural Constraints ◽  
Reverse Monte Carlo ◽  
Three Body ◽  
Reverse Monte Carlo Method

A spatial atomic distribution model of liquid S (L-S) and liquid Te (L-Te) was generated by using the experimental diffraction data and reverse Monte Carlo method without applying structural constraints. The obtained models have been analysed in terms of near-atomic-neighbour, bond-angle distribution, three-body correlations and chain statistics. The analysis of the generated models has shown that the three-dimensional structure of the investigated liquids can be well described as a network of short chains.

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