Steady-State Formulation for Stress and Distortion of Welds

1994 ◽  
Vol 116 (4) ◽  
pp. 467-474 ◽  
Author(s):  
M. Gu ◽  
J. A. Goldak
Keyword(s):  
Thermal Stress ◽  
Steady State ◽  
Three Dimensional ◽  
Significant Gain ◽  
Free Boundaries ◽  
Flow Lines ◽  
Eulerian Formulation ◽  
Noticeable Reduction ◽  
Computing Speed ◽  
Lagrangian Frame

A steady state formulation has been developed for thermal stress analysis. It uses features from both the Lagrangian formulation and the Eulerian formulation. The mesh sits on an Eulerian frame but deforms as if in the Lagrangian frame. Therefore, it is suitable for steady state problems with free boundaries. History dependent parameters are integrated along flow lines. A significant gain in computing speed and/or spatial resolution over transient analyses has been achieved together with a noticeable reduction for memory requirements. Numerical results are given for a three-dimensional analysis of edge weld.

Some Implications of Dundurs' Theorem for Thermoelastic Contact and Crack Problems

1980 ◽  
Vol 22 (5) ◽  
pp. 229-232 ◽  
Author(s):  
J. R. Barber
Keyword(s):  
Steady State ◽  
Thick Plate ◽  
Line Element ◽  
Three Dimensional ◽  
Contact Problems ◽  
Free Boundaries ◽  
Principal Curvatures ◽  
State Heat ◽  
Crack Problems ◽  
Steady State Heat

It is well known that a simply-connected isotropic elastic body in a state of plane strain and with traction-free boundaries remains free of stress if it is subject to steady-state heat conduction. A recent theorem due to Dundurs shows that in this state the curvature of any initially straight line element is proportional to the heat flux across the line element. A closely related three dimensional result is proved for the sum of the principal curvatures of planes parallel to the faces of an infinite thick plate. These results have certain implications for thermoelastic crack and contact problems. For example: (i) thermal distortion has no effect on the contact pressure distribution at an insulated interface or at an interface between two similar materials, (ii) the thermal stress in a cracked solid depends on the temperature field only through the value of a certain constant related to the average temperature difference across the crack, (iii) steady-state heat flow induces no stresses in an axisymmetric thick plate containing an external crack.

An Exploratory Study of Three-Dimensional Photothermoelasticity

1961 ◽  
Vol 28 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Herbert Tramposch ◽  
George Gerard
Keyword(s):  
Thermal Stress ◽  
Steady State ◽  
Mechanical Loading ◽  
Exploratory Study ◽  
Three Dimensional ◽  
General Applicability ◽  
Sandwich Technique ◽  
Strength Tests ◽  
Fringe Patterns ◽  
Walled Cylinder

A sandwich technique which utilizes an embedded polariscope consisting of two sheets of polarizing material cemented within a plastic model was evaluated for application to three-dimensional photothermoelasticity. The evaluation included strength tests of cemented joints, photoelastic tests of simple bending models and a sphere, all under mechanical loading. The technique proved to be rather simple to apply particularly since the resulting fringe patterns are readily interpreted. The sandwich technique was then applied to thermal-stress problems associated with a thick-walled cylinder under steady-state conditions. The experimental results correlated well with theory. The results obtained indicate the general applicability of the sandwich technique to three-dimensional stress problems generated by mechanical or thermal loads. It is noted that since other experimental thermal-stress-analysis methods are not highly developed, photothermoelasticity would seem to be particularly useful.

scholarly journals The first observation of 4D tomography measurement of plasma structures and fluctuations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chanho Moon ◽  
Kotaro Yamasaki ◽  
Yoshihiko Nagashima ◽  
Shigeru Inagaki ◽  
Takeshi Ido ◽  
...  
Keyword(s):  
Steady State ◽  
Three Dimensional ◽  
Axial Direction ◽  
Axial Position ◽  
Entire Cross Section ◽  
Helicon Plasma ◽  
Emission Profile ◽  
Dimensional Measurement ◽  
Tomography System ◽  
Three Dimensional Measurement

AbstractA tomography system is installed as one of the diagnostics of new age to examine the three-dimensional characteristics of structure and dynamics including fluctuations of a linear magnetized helicon plasma. The system is composed of three sets of tomography components located at different axial positions. Each tomography component can measure the two-dimensional emission profile over the entire cross-section of plasma at different axial positions in a sufficient temporal scale to detect the fluctuations. The four-dimensional measurement including time and space successfully obtains the following three results that have never been found without three-dimensional measurement: (1) in the production phase, the plasma front propagates from the antenna toward the end plate with an ion acoustic velocity. (2) In the steady state, the plasma emission profile is inhomogeneous, and decreases along the axial direction in the presence of the azimuthal asymmetry. Furthermore, (3) in the steady state, the fluctuations should originate from a particular axial position located downward from the helicon antenna.

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