The objective of this paper is to describe an experimental method used in the determination of the stress distribution produced by gravitational loading in a two-dimensional gelatin model of heavy disk, and then the directions of principal stress, values and distributions of stresses in heavy disk were made clear. The test result for one of the heavy disk investigated were compared with those obtained by Teodorescu's theoretical value.

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There is an undetermined problem for analysis of shear stresses by means of photoelastic experiment that uses of the fringe data showing the principal stress difference and the isoclinic data showing the principal stress directions. It is undistinctness of the isoclinic lines. This paper makes propose of a new method of the shear stress measurements, we named “compound fringe method”, for slices from stress freeging specimen without using any data of isoclinic lines.
To analyze the shear stress distribution in slices by the method, it needs only two fringe data, one is the fringe data in the slices and the another is the fringe data (compound fringe data) in the same slice under added known stresses.
We demonstrated the method by both of the experiments and the computer simulations.

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In order to measure small displacement distributions changing with time, moire interferometry is applied. The fringe patterns with carriers are analyzed by using the Fourier transform moire and grid method. This method gives fast, accurate and high-sensitive measurement.
Thermal deformation of electronic parts (three-terminal regulators) with and without a radiator is analyzed, and the effect of the radiator is investigated.

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Dovetail of a steam turbine is a one of the most important factors which effect reliability and performance of a turbine plant. In these years, however, the condition under which steam turbines are operated has become severer. The increase in centrifugal force, due to variation sway and fluctuation of load, is listed. As quite heavy load workes on a turbine blade structure. It is important to estimate stress distribution with experiments. Althouh there are many reports about turbine blades, most of the results are examined by two dimensional stress analysis and static stress. In our present study, we have analyzed the stress distribution of turbine blades with practically simulated turbine blades by means of three dimensional stress analysis method in frozen photoelasticity.
There are two types in turbine dovetail. One is a Straddle type dovetail, the other is a Christmastree type dovetail. We obtained stress distribution and stress concentration factorin terms of strength comparision between two types. The results are shown from the viewpointof stress concentration. And the normal stress around the surface and the shear stress on the Straddle type dovetail are higher than those of Christmastree type dovetail.

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The thermal stress intensity factors of the plate with an edge crack is evaluated from the photothermoelastic experiment by moderate heatlng. Several oblique cracks are cut on one edge of model plates and the edge with a crack is heated suddenly. The model plate is sandwlched by polymethyl methacrylate plates and the observed isochromatic fringe is recorded photographically at several specified time intervals.
The digital image data processing system is fully utilized to get the good thinning image of the whole field data of the isochromatic fringe pattern. The coordinate system is affixed at the crack tip and the data points are selected and collected on the thinning image. The fringe number of the image and the collected data are used to analyze the thermal stress intensity factors of mode I and mode II by the method proposed by Sanford and Dally. Also, the effective thermal stress intensity factor is evaluated from those results.

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A clue to a photoelastic computer-aided tomography similar to the x-ray CT is investigated. The study deals with an automatic and nondestructive method of measuring the differences of rotating secondary principal stresses and their directions in a three dimensional model subjected to an arbitrary stress distribution. The method takes two steps as follows. One is to measure the Stokes parameters of the light beam emergent from the model. The other is to slice the model optically by using the scattered light caused by an incident beam. The former gives great facility for an automatic measurement, and the latter is very useful for a nondestructive measurement. The paper I proposes an automatic and nondestructive method of evaluating the differences of rotaing secondary principal stresses and their directions in three dimensional photoelasticity. The algorism of the method is numerically examined by using a known. theoretical stress distrbution having the rotation effect. The stress distribution along a diameter of a cylindrical bar submitted to tension and torsion is used as an example. The algorism is successful in the examination.

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Shearing stress distributions of beam by a difference method is demonstrated for fringe intensity from three-dimensional frozen stress models. The effects of the bending deflection and fiber stress were corrected satisfactorily. Two analytical solutions for solid and hollow round bars under a shearing load was worked out to verify the accuracy of the experimental procedure employed, and then comparison of the results obtained experimentally and theoretically indicates that the accuracy of the procedure is satisfactory. The validity of the difference method in the analysis of three-dimensional shearing problems is verified.

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