Lifting wings of optimum shape in a viscous hypersonic stream

1995 ◽  
Vol 30 (6) ◽  
pp. 934-942
Author(s):  
V. N. Golubkin
Keyword(s):  
Optimum Shape ◽  
Hypersonic Stream

Imperialist Competitive Algorithm for Multiobjective Optimization of Ellipsoidal Head of Pressure Vessel

2011 ◽  
Vol 110-116 ◽  
pp. 3422-3428 ◽  
Author(s):  
Behzad Abdi ◽  
Hamid Mozafari ◽  
Ayob Amran ◽  
Roya Kohandel
Keyword(s):  
Genetic Algorithm ◽  
Pressure Vessel ◽  
Shear Force ◽  
Minimum Weight ◽  
Bending Moment ◽  
Imperialist Competitive Algorithm ◽  
Optimum Shape ◽  
Working Pressure ◽  
Competitive Algorithm ◽  
Bending Stresses

This work devoted to an ellipsoidal head of pressure vessel under internal pressure load. The analysis is aimed at finding an optimum weight of ellipsoidal head of pressure vessel due to maximum working pressure that ensures its full charge with stresses by using imperialist competitive algorithm and genetic algorithm. In head of pressure vessel the region of its joint with the cylindrical shell is loaded with shear force and bending moments. The load causes high bending stresses in the region of the joint. Therefore, imperialist competitive algorithm was used here to find the optimum shape of a head with minimum weight and maximum working pressure which the shear force and the bending moment moved toward zero. Two different size ellipsoidal head examples are selected and studied. The imperialist competitive algorithm results are compared with the genetic algorithm results.

Crystallization of Amorphous Sputtered NiTi Shape-Memory Alloy Films

1995 ◽  
Vol 398 ◽  
Author(s):  
F.F. Gong ◽  
H.M. Shen ◽  
Y.N. Wang
Keyword(s):  
Shape Memory ◽  
Annealing Temperature ◽  
Optimum Shape ◽  
Niti Shape Memory Alloy ◽  
X Ray Diffraction ◽  
Initial Stage ◽  
Average Grain Size ◽  
Optimum Heat ◽  
Diffraction Patterns ◽  
Optimum Heat Treatment

ABSTRACTThe crystallization of amorphous sputtered NiTi films was investigated for selected heat treatments. From x-ray diffraction patterns, when the films were annealed below the crystallization temperature, the intensity of the broad maximum centered at 2θ = 43.5° increased with increasing the annealing temperature and time. When the films were annealed at 550°C for 0.5hr, parent B2 phase and Ni4Ti3 precipitates appeared. For annealing temperature above 700°C, the films showed embrittlement and volatilization. Therefore the optimum heat treatment for the optimum shape memory effect is found. The average grain size increased slowly in the initial stage of annealing but remained almost unchanged when the films were annealed for more than 1hr. This is because the grain boundary grooving caused by the titanium at a certain temperature volatilization seriously hinder the grain growth.

Minimum Weight of Tapered Round Thin-Walled Columns

1952 ◽  
Vol 19 (3) ◽  
pp. 375-380
Author(s):  
Morris Feigen
Keyword(s):  
Wall Thickness ◽  
Minimum Weight ◽  
Weight Ratio ◽  
Optimum Shape ◽  
Bending Stress ◽  
Round Tube ◽  
Cylindrical Column ◽  
Truncated Cone ◽  
Thin Walled ◽  
Tapered Column

Abstract It is shown that the optimum wall thickness of a cylindrical round tube column is a function of load only and is independent of diameter. The optimum wall thickness of a tapered round thin-walled column is found to be constant along its length. The optimum shape of a tapered round thin-walled column is derived, being that column whose bending stress in the buckled state is constant along its length. The weight ratio of the optimum tapered column to an equal-strength optimum cylindrical column is found to be 0.8924. It is shown that a double truncated cone whose diameter ratio is in the range 0.35 ⩽ D1/D2 ⩽ 0.50 closely approaches the optimum column. If it is specified that no portion of the double truncated cone shall yield, then the weight advantage of the cone over the cylindrical column is rapidly lost as the stress in the cylindrical column approaches the yield stress. In the inelastic range the weight advantage of the tapered column will be less than in the elastic range.

Groove Shape Optimization of Thrust Air Bearing for Small Size Spindle Considering the Processing Errors

2018 ◽  
Author(s):  
Masayuki Ochiai ◽  
Naoya Kato ◽  
Hiromu Hashimoto
Keyword(s):  
Probability Distribution ◽  
Laser Processing ◽  
Thrust Bearing ◽  
Groove Depth ◽  
Spindle Motor ◽  
Processing Method ◽  
Optimum Shape ◽  
Air Bearing ◽  
Machining Error ◽  
Processing Errors

In this research, we aim to examine the usefulness of the newly developed spindle motor proposed by Ochiai. Since machining error due to tool wear etc. used for microfabrication can be ignored, laser processing was used as a processing method. Thrust bearing grooves were generated by laser processing, and variation in groove depth was observed. Finally, the optimum shape of the thrust bearing groove was obtained by robust optimization using the probability distribution that can be approximated from the obtained machining error.

scholarly journals Fluid boundaries shaping using the method of kinetic balance

2006 ◽  
Vol 10 (4) ◽  
pp. 153-162
Author(s):  
Miroslav Benisek ◽  
Svetislav Cantrak ◽  
Milos Nedeljkovic ◽  
Djordje Cantrak ◽  
Dejan Ilic ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Fluid Mechanics ◽  
Cross Sections ◽  
Hydraulic Engineering ◽  
Optimum Shape ◽  
Curved Channels ◽  
Unsteady Fluid Flow ◽  
Unsteady Fluid ◽  
Flow Boundaries ◽  
Dead Water

Fluid flow in curved channels with various cross-sections, as a common problem in theoretical and applied fluid mechanics, is a very complex and quite undiscovered phenomenon. Defining the optimum shape of the fluid flow boundaries, which would ensure minimum undesirable phenomena, like "dead water" zones, unsteady fluid flow, etc., is one of the crucial hydraulic engineering?s task. Method of kinetic balance is described and used for this purpose, what is illustrated with few examples. .

scholarly journals Optimum Shape of High Speed Impactor for Concrete Targets Using PSOA Heuristic

Engineering ◽  
2010 ◽  
Vol 02 (04) ◽  
pp. 257-262 ◽  
Author(s):  
Francesco Ragnedda ◽  
Mauro Serra
Keyword(s):  
High Speed ◽  
Optimum Shape

scholarly journals Analysis on Heat Transmission and Fluid Flow Attributes in Solar Air Accumulator Passage with Diverse Faux Jaggedness Silhouettes on Absorber Panel

2019 ◽  
Vol 8 (5S3) ◽  
pp. 32-41 ◽  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Optimum Shape ◽  
Solar Air Heater ◽  
Artificial Roughness ◽  
Heat Transmission ◽  
Number Range ◽  
Elliptical Shape ◽  
Shape Pattern

There is a necessity to investigate the heat transmission and fluid cascade peculiarities of solar air convectors using varying faux irregular surface and shapes on absorber sheet, so that the solar devices utilize maximum amount of available solar radiated heat energy during day time. These artificial roughness shapes are use for the enhancement of thermal performance. This need arises from the fact that the heat circulation and liquid cascade trait have been investigated by the previous investigators only for the cases that differ considerably from those relevant to solar air brazier having different screen matrix placed in the planes parallel to the flow direction and that the radiant energy being absorbed in depth. In our present research paper we investigating experimentally the behavior of artificial irregularities located over absorber platter of solar air heater vessel of varying shapes like trapezoidal, sin wave, rectangular, alternative elliptical shape pattern etc, with different Reynolds Number range 4000 to 24000, mass flow rate on Nusselt Number and Friction Factor and also find the suitable optimum shape for heat transmission enhancement. The results indicated the best heat transfer enhancement results for the alternative elliptical shape pattern among other artificial roughness with range of 0.0786kg/s – 0.475kg/s mass flow rate with thermal efficiency near about 78%.

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