Analysis of a stiffener intersection eccentricity in a steel containment

Containment structures have several regions in which the continuity of the cylindrical pressure boundary is interrupted, e.g., shell penetrations, discontinuous stiffeners, and changes in the shell thickness. Significant strain concentrations can occur in these areas of discontinuity. The Sandia National Laboratories 1:8-scale steel containment equipment hatch was analyzed as an example of an eccentricity at a stiffener intersection.A portion of the as-built 1:8-scale model was modeled with the ANSYS general purpose finite element program using triangular, thin shell finite elements. The overall size of the model was determined from Saint-Venant type considerations of the stress field around the hatch. Shell elements were used to model the ring and formed stiffeners. Geometric and material nonlinear behavior were included. The model was loaded using discrete load steps up to a pressure of 165 psig. At this pressure, the maximum strain was 19.7 percent in the formed stiffener near its intersection with the ring stiffener. The finite element solution demonstrated the very localized nature of the strain field near the ring/formed stiffener intersection.In an attempt to reduce analysis costs, a small portion of the 1:8-scale model immediately surrounding the ring/formed stiffener intersection was selected for further analysis. Two smaller models, a ring/formed stiffener intersection and a ring/circular stiffener intersection, were studied. The models were significantly smaller than the regions used previously. A comparison of the two intersection models showed that the circular stiffener is a more efficient configuration.     

Thermal image analysis for polygraph testing

We have designed, developed, and tested a very promising thermal image analysis method for polygraph testing. The method achieved a correct classification rate of CCR= 84% on the test population to our avail. This method, once refined, can serve as an additional channel for increasing the reliability and accuracy of traditional polygraph examination. We extract subtle facial temperature fluctuation patterns through nonlinear heat transfer modeling. The modeling transforms raw thermal data to blood flow rate information. Then, we use the slope of the average periorbital blood flow rate as the feature of a binary classification scheme. The results come to support our previous laboratory findings about the importance of periorbital blood flow in anxious states.     

Phase transformations in highly disperse powders during their rapid heating and cooling

Phase transformations in particles of ultrafine powders of graphite, hexagonal boron nitride, and quartz during rapid heating and cooling by passage through a laser beam were investigated. A continuous infrared laser with a wavelength of 10.6 μm was used as a heat source through which the powders were recycled several times. Methods of concentrating the product phases are described. Particles of diamond, carbides, cubic boron nitride, koesite and stishovite were obtained in the mixed products.     

Tube-shaping unit — A way of improving the quality of shaped tubes

Lenin Dnepropetrovsk Pipe Plant. Translated from Metallurg, No. 8, p. 39, August, 1989.     

Three ways to implement interfacial techniques: application tomeasurements of chromatic dispersion, birefringence, and nonlinearsusceptibilities

Depending on the spectal width of the source illuminating an interferometer, measurement procedures can utilize either the whole interferogram, or only the fringe envelope, or only the fringe quick oscillations. With an ultraband spectrum source, a simplified adaptation of the methods of Fourier transform spectroscopy yields the variations of the test-fiber propagation constant over the whole wavelength-interval of the source. Chromatic dispersion can then be computed from a single interferogram. With narrower spectrum sources, only the fringe envelopes are utilized and yield measurements of mode delay, with application to chromatic and polarization mode dispersion. In this case, however, interferograms at several wavelengths are necessary. With even narrower spectrum sources, the fringe quick oscillations provide measurements of phase shifts, related to changes in the mode propagation constant, when outside perturbations are applied to the test fiber. A direct method for measuring the third-order nonlinear susceptibilities is discussed. In this case the outside perturbation is an intense pump laser field     

Analytic approach to the computation of the temperature distribution in multilayer structures under heating by cw scanning laser radiation

By using integral transform methods, an approach is developed to the solution of a problem on the temprature distribution in multilayer structures heated by cw scanning laser radiation, with phase transitions in the layers taken into account.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 6, pp. 1000–1010, December, 1987.     

A comparison between the axial flux and the radial flux structures for PM synchronous motors

The aim of this paper is the comparison of the axial flux (AF) structures versus the conventional radial flux (RF) structures for permanent-magnet synchronous motors. The comparison procedure is based on simple thermal considerations. Two motor typologies are chosen and compared in terms of delivered electromagnetic torque. The comparison is developed for different motor dimensions and the pole number influence is put into evidence. The paper reports the complete comparison procedure and the related results analysis. The obtained results show that, when the axial length is very short and the pole number is high, the AF motors can be an attractive alternative to the conventional RF solutions.