Search results for "Paraboloid"
showing 4 items of 4 documents
Some observations on metal cutting with reference to the mechanical characteristics of working materials
1972
The hypothesis of the minimum work of Merchant is applied to materials with different yield points in traction and in simple compression on the assumption that these materials yield in accordance with the paraboloid yield-criterion. The experimental data obtained from cutting tests like those described in this paper may apparently be in good agreement with theoretical results. But closer examination reveals that the values of the shear angle φ depend largely on the cutting speed and on the feed p. r. All relationship between φ and (λ — γ) (difference between the friction angle on the rake face and the rake angle) must therefore take in account the influence of the above variables.
Drawing and extruding: Theoretical and approximate formulas
1969
The problem of drawing of wires and of strips has been treated in several studies; among these the studies of Sachs seem essential. However, the results deduced according to similar theories are not always in accordance with the experimental results: reduction of area or of thickness are in fact usually smaller than those resulting from the theory. This is in dependance of the fact that Sachs has adopted the Limiting Condition of Yielding by v. Mises, according to which the limit values of stress in traction and compression are equal. More recently other AA. (Alberti, Noto La Diega, Bugini), admitting the Limiting Condition of Yielding by A. (or of the Paraboloid of Revolution) of which we …
Hyperboloid and Parabolid in Orthogonal Axonometric
2012
This paper presents the issue of a long research on the representation of the complex surface in descriptive geometry. The ability to use the different techniques of representation aims to achieve results that you didn’t image before. In Palermo University, at the Engineering School, the researcher involved the study on the simplify of the so elaborated way to represent the geometry and its applications in architecture buildings and engineering implants. We just report below the application methods to represent two of the most used quadric surfaces in the practice of buildings. We are talking about Hyperboloid and Paraboloid quadric surface represented in axonometric projecting. This method…
Emission and null coordinates: geometrical properties and physical construction
2011
A Relativistic Positioning System is defined by four clocks (emitters) broadcasting their proper time. Then, every event reached by the signals is naturally labeled by these four times which are the emission coordinates of this event. The coordinate hypersurfaces of the emission coordinates are the future light cones based on the emitter trajectories. For this reason the emission coordinates have been also named null coordinates or light coordinates. Nevertheless, other coordinate systems used in different relativistic contexts have the own right to be named null or light coordinates. Here we analyze when one can say that a coordinate is a null coordinate and when one can say that a coordin…