On the effect of rotating secondary principal stresses in scattered-light photoelasticity

1973 ◽  
Vol 13 (7) ◽  
pp. 273-279 ◽  
Author(s):  
Jan Cernosek
Keyword(s):  
Scattered Light ◽  
Principal Stresses ◽  
Secondary Principal

On the Meaning of Isoclinic Parameters in the Plastic State in Cellulose Nitrate

1962 ◽  
Vol 29 (1) ◽  
pp. 1-6 ◽  
Author(s):  
M. M. Frocht ◽  
Y. F. Cheng
Keyword(s):  
Scattered Light ◽  
Three Dimensional ◽  
Plastic State ◽  
Basic Question ◽  
Stress Distributions ◽  
Principal Stresses ◽  
Special Equipment ◽  
Secondary Principal ◽  
Series Of Experiments ◽  
Stress Optic Law

In applying the shear-difference method to the determination of stress distributions in photo plasticity, a basic question arises whether, under plastic flow, the isoclinic parameters represent the directions of the secondary principal stresses. Special equipment, new techniques, and a series of experiments are described to study this problem. Tests were made with stress systems which varied in magnitude and direction at normal and oblique incidence, and at strains for which a one-to-one stress-optic relation exists as well as at strains for which it breaks down. Typical results are given. These findings together with the method of scattered light and an appropriate stress-optic law may provide a foundation for three-dimensional photoplasticity. The effects described are limited to loading. Cases of loading plus unloading are not considered in the present paper.

scholarly journals Photoelastic Analysis of Three-Dimensional Stress Systems using Scattered Light

1940 ◽  
Vol 44 (349) ◽  
pp. 74-88 ◽  
Author(s):  
R. Weller ◽  
J. K. Bussey
Keyword(s):  
Elementary Theory ◽  
Scattered Light ◽  
Three Dimensional ◽  
Plane Section ◽  
Stress System ◽  
Principal Stresses ◽  
State Of Stress ◽  
Polarised Light ◽  
Photoelastic Analysis ◽  
Good Agreement

SummaryA method has been developed for making photoelastic analyses of threedimensional stress systems by utilising the polarisation phenomena associated with the scattering of light. By this method, the maximum shear and the directions of the three principal stresses at any point within a model can be determined, and the two principal stresses at a free-bounding surface can be separately evaluated. Polarised light is projected into the model through a slit so that it illuminates a plane section. The light is continuously analysed along its path by scattering and the state of stress in the illuminated section is obtained. By means of a series of such sections, the entire stress field may be explored. The method was used to analyse the stress system of a simple beam in bending. The results were found to be in good agreement with those expected from elementary theory.

Effect of rotating secondary principal axes in scattered-light photoelasticity

1970 ◽  
Vol 10 (4) ◽  
pp. 160-165 ◽  
Author(s):  
R. W. Aderholdt ◽  
J. M. McKinney ◽  
W. F. Ranson ◽  
W. F. Swinson
Keyword(s):  
Scattered Light ◽  
Secondary Principal ◽  
Principal Axes

Magnetic resonance in the noise in the intensity of scattered light

1987 ◽  
Vol 153 (10) ◽  
pp. 363 ◽  
Author(s):  
Evgenii B. Aleksandrov ◽  
V.S. Zapasskii
Keyword(s):  
Magnetic Resonance ◽  
Scattered Light

Comparison of Conventional and Pontic Fixed Partial Dentures Over Implants Using the Finite Element Method: Three-Dimensional Analysis of Cortical and Medullary Bone Stress

2020 ◽  
Vol 46 (3) ◽  
pp. 175-181
Author(s):  
Marcelo Bighetti Toniollo ◽  
Mikaelly dos Santos Sá ◽  
Fernanda Pereira Silva ◽  
Giselle Rodrigues Reis ◽  
Ana Paula Macedo ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Medullary Bone ◽  
Principal Stresses ◽  
Bone Stress ◽  
Bone Damage ◽  
Rehabilitation System ◽  
Minimum Requirements

Rehabilitation with implant prostheses in posterior areas requires the maximum number of possible implants due to the greater masticatory load of the region. However, the necessary minimum requirements are not always present in full. This project analyzed the minimum principal stresses (TMiP, representative of the compressive stress) to the friable structures, specifically the vestibular face of the cortical bone and the vestibular and internal/lingual face of the medullary bone. The experimental groups were as follows: the regular splinted group (GR), with a conventional infrastructure on 3 regular-length Morse taper implants (4 × 11 mm); and the regular pontic group (GP), with a pontic infrastructure on 2 regular-length Morse taper implants (4 × 11 mm). The results showed that the TMiP of the cortical and medullary bones were greater for the GP in regions surrounding the implants (especially in the cervical and apical areas of the same region) but they did not reach bone damage levels, at least under the loads applied in this study. It was concluded that greater stress observed in the GP demonstrates greater fragility with this modality of rehabilitation; this should draw the professional's attention to possible biomechanical implications. Whenever possible, professionals should give preference to use of a greater number of implants in the rehabilitation system, with a focus on preserving the supporting tissue with the generation of less intense stresses.

Influence exerted by underground excavation shape and by effective stresses on the formation of a tensile strain zone at a depth greater than 1 km

2020 ◽  
pp. 67-75
Author(s):  
Van Min Nguyen ◽  
V. A. Eremenko ◽  
M. A. Sukhorukova ◽  
S. S. Shermatova
Keyword(s):  
Rock Mass ◽  
Cross Sections ◽  
Tensile Strain ◽  
Rock Fracture ◽  
Strain Analysis ◽  
Surrounding Rock ◽  
Underground Excavation ◽  
Secondary Stress ◽  
Principal Stresses ◽  
Mining Depth

The article presents the studies into the secondary stress field formed in surrounding rock mass around underground excavations of different cross-sections and the variants of principal stresses at a mining depth greater than 1 km. The stress-strain analysis of surrounding rock mass around development headings was performed in Map3D environment. The obtained results of the quantitative analysis are currently used in adjustment of the model over the whole period of heading and support of operating mine openings. The estimates of the assumed parameters of excavations, as well as the calculations of micro-strains in surrounding rock mass by three scenarios are given. During heading in the test area in granite, dense fracturing and formation of tensile strain zone proceeds from the boundary of e ≥ 350me and is used to determine rough distances from the roof ( H roof) and sidewalls ( H side) of an underground excavation to the 3 boundary e = 350me (probable rock fracture zone). The modeling has determined the structure of secondary stress and strain fields in the conditions of heading operations at great depths.

A Time-Resolved Low-Angle Light Scattering Apparatus. Application to Phase Separation Problems in Polymer Systems

2001 ◽  
Vol 66 (6) ◽  
pp. 973-982 ◽  
Author(s):  
Čestmír Koňák ◽  
Jaroslav Holoubek ◽  
Petr Štěpánek
Keyword(s):  
Phase Separation ◽  
Light Scattering ◽  
Signal To Noise Ratio ◽  
Scattered Light ◽  
Ccd Camera ◽  
Time Resolved ◽  
Polymer Systems ◽  
Software Analysis ◽  
Phase Separation Kinetics ◽  
Small Angle Light Scattering

A time-resolved small-angle light scattering apparatus equipped with azimuthal integration by means of a conical lens or software analysis of scattering patterns detected with a CCD camera was developed. Averaging allows a significant reduction of the signal-to-noise ratio of scattered light and makes this technique suitable for investigation of phase separation kinetics. Examples of applications to time evolution of phase separation in concentrated statistical copolymer solutions and dissolution of phase-separated domains in polymer blends are given.

Nondiffusive Brownian Motion Studied by Diffusing-Wave Spectroscopy

1989 ◽  
Vol 177 ◽  
Author(s):  
D. J. Pine ◽  
D. A. Weitz ◽  
D. J. Durian ◽  
P. N. Pusey ◽  
R. J. A. Tough
Keyword(s):  
Autocorrelation Function ◽  
Colloidal Particles ◽  
Scattered Light ◽  
Short Time Scale ◽  
Velocity Autocorrelation Function ◽  
Velocity Autocorrelation ◽  
Power Law Decay ◽  
Brownian Particles ◽  
Short Time ◽  
Surrounding Fluid

ABSTRACTOn a short time scale, Brownian particles undergo a transition from initially ballistic trajectories to diffusive motion. Hydrodynamic interactions with the surrounding fluid lead to a complex time dependence of this transition. We directly probe this transition for colloidal particles by measuring the autocorrelation function of multiply scattered light and observe the effects of the slow power-law decay of the velocity autocorrelation function.

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