scholarly journals Analytical model for determining allowances for elastomer constrained bending of aircraft parts

2020 ◽  
Vol 19 (3) ◽  
pp. 73-84
Author(s):  
V. K. Moiseev ◽  
E. G. Gromova ◽  
O. V. Lomovskoi ◽  
M. N. Mantusov ◽  
A. N. Plotnikov ◽  
...  
Keyword(s):  
Analytical Model ◽  
Lower Boundary ◽  
Critical Factor ◽  
Second Step ◽  
Plastic Deformations ◽  
Reduced Height ◽  
Inner Surface ◽  
Bending Radius ◽  
Constrained Bending ◽  
Side Bending

In the article, the authors present a method of constrained bending of aircraft sheet parts with curved sides by an elastic medium. The process of conducting constrained bending is described. A schematic description of the process is presented. The manufacture of a part is carried out in two steps. As a result of the first step, a piece is obtained with thinning in the radius part, the second step is accomplished with a unit die of reduced height. The resulting wave of excess material is deformed along the radius of the bending mandrel. In the finished part, an increase in the thickness of the workpiece is observed in the zone of the bending radius. The wave of excess material is formed due to a special allowance, the size of which is the critical factor for achieving this increase in thickness. The analytical model for determining the allowance is based on generally accepted assumptions and principles for calculating process parameters. To determine the allowance, an approximation of the shape of the excess wave by a tangential function is proposed. This allows you to get an analytical dependence that relates the geometry of the part and the thickening of the wall to the size of the allowance. The size of the allowance is limited to a certain range, the lower boundary of which is determined by the onset of plastic deformations, the upper one - by the possibility of loss of stability, leading to irreparable spoilage. The results are illustrated by graphs of the dependence of the minimum and maximum allowance for the side height on the ratios of the workpiece wall thickness, the radius of the side bending and the radius of the side in plan. Characteristic curves and analytical dependencies are presented in a dimensionless form, where the geometric parameters are assigned to the radius of the bending tool, that is, to the radius of bending of the part side on the inner surface.

Improvement of Method and Mechanism for Conical and Paraboloid Springs Hardening

2021 ◽  
Vol 1037 ◽  
pp. 227-232
Author(s):  
Nikita A. Zemlyanushnov ◽  
Nadezhda Y. Zemlyanushnova
Keyword(s):  
New Method ◽  
Cylindrical Shape ◽  
Plastic Deformations ◽  
Conical Shape ◽  
Inner Surface ◽  
Hardening Mechanisms ◽  
The Difference ◽  
Compression Springs

The disadvantage of the known methods of hardening springs is the impossibility of their use when hardening springs of a conical shape or of a shape of a paraboloid of rotation, since they are intended only for cylindrical shape springs and are not suitable for conical shape springs or those of a shape of a paraboloid of rotation specifically because of the difference in the shape of the springs. One of the disadvantages of the known springs hardening mechanisms is the impossibility of hardening the inner surface of the conical compression springs. A new method of hardening springs is proposed, the unmatched advantage of which is the ability to create plastic deformations on the inner and outer surfaces of the spring coils compressed to contact and on the surfaces along the line of contact between the coils. A new advantageous mechanism for hardening springs is proposed, which makes it possible to harden the inner surface of compression springs having a conical shape or a paraboloid shape of rotation, in a compressed state.

Deriving an Analytical Model for Hydro-Magnetic Micro Flow Controller

2008 ◽  
Author(s):  
Mahdi Esmaily Moghadam ◽  
Mohammad Behshad Shafii
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Magnetic Particles ◽  
Switching Time ◽  
Critical Factor ◽  
Pressure Head ◽  
Experimental Results ◽  
Working Fluid ◽  
Effective Parameters ◽  
Flow Controller

Fluid control, namely pumping and valving, is a critical factor in the performance of micro-fluidic systems. In recent years a variety of micro-fluidic systems are developed for the purpose of miniaturizing fluid handling, and chemical analysis to develop Lab On a Chip (LOC) technology. The mentioned facts resulted in design and fabrication of a novel hydro-magnetic flow controller. The idea behind this device is that magnetic particles, mixed and dispersed in a carrier liquid, can be accumulated in the form of a piston. Depending upon dragging speed of these pistons, which itself is a function of switching time, this device can be used to either increase (pumping) or decrease (valving) the flow rate. The valving characteristic of the setup, which occurs at higher switching times, was concurrent with regular forming of pistons in micro-tube. Experimental results in this part show a meaningful trend for the flow rate changes versus effective parameters of the flow. Considering this fact, lead us to propose a mathematical (analytical) model, which is a function of concerning parameters. Pressure head difference, concentration, material of particles, switching time, working fluid and, switching mode, depending on their complexity, have been introduced into the mathematical model, completely theoretically or semi-experimentally. The equations were derived based on the recognition of the leakage flow through the formed pistons and the pumped flow after each switching. The model was validated by the experimental results for nickel particles of less than 10μ in diameter and 0.5 gNi/100ccH2O concentration in water for a defined pressure head in a pressure driven flow setup.

Electromagnetic Nondestructive Testing Model and Surface Magnetic Field Analysis for Circumferential Cracks on Metal Rod

2019 ◽  
Vol 2 (4) ◽  
Author(s):  
Feng Jiang ◽  
Shulin Liu ◽  
Shaojie Xin ◽  
Hongli Zhang
Keyword(s):  
Magnetic Field ◽  
Analytical Model ◽  
Magnetic Induction ◽  
Crack Depth ◽  
Field Analysis ◽  
Surface Magnetic Field ◽  
Circumferential Crack ◽  
Inner Surface ◽  
Magnetic Induction Intensity ◽  
The Magnetic Field

Abstract In this paper, an analytical model for a metal rod with a coating layer is proposed to evaluate circumferential crack from the signals of the surface magnetic field. In the proposed model, magnetic vector equations for four regions of space were built, and series expressions of the magnetic field were proposed by the truncated region eigenfunction method. The calculation results can show the three-dimensional distribution of axial and radial magnetic induction intensities on the surface of a metal rod clearly. In addition, the analytical model is verified by using comsol finite element simulation, which also demonstrates that induced eddy currents on the inner surface of the metal rod with cracks appear to be propelled toward the inner layer of the metal rod and the presence of a circumferential crack directly causes a decrease in the induced eddy current on the inner surface of the rod. The results calculated from the analytical model indicated that the model is capable of providing an accurate variation in the magnetic field due to circumferential cracks at different depths. The analytical results showed that the radial magnetic induction intensity increases by 0.16 × 10−3 T, while the axial magnetic induction intensity decreases by 0.3 × 10−3 T as the crack depth increases from 0 to 3 mm.

Elastic-Plastic Equilibrium of a Hollow Cylinder from Inhomogeneous Perfectly Plastic Material

2013 ◽  
Vol 405-408 ◽  
pp. 3182-3185 ◽  
Author(s):  
Vladimir I. Andreev
Keyword(s):  
Cylindrical Shell ◽  
Elastic Modulus ◽  
Plastic Material ◽  
Continuous Functions ◽  
Plastic Deformations ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
External Pressures ◽  
Inner Surface ◽  
Plastic Zones

The paper presents the solution of elastic-plastic problem of the equilibrium of a thick-walled cylindrical shell under the influence of internal and external pressures. We consider a perfectly plastic material, elastic modulus and yield strength which are continuous functions of the radius. It is shown that plastic deformations may occur on both the inner surface of the shell and the inside of its wall. Defined stresses and strains in the elastic and plastic zones, as well the displacements in the shell until fracture.

scholarly journals Tornado funnel-shaped cloud as convection in a cloudy layer

2009 ◽  
Vol 3 (1) ◽  
pp. 17-21
Author(s):  
M. V. Zavolgenskiy ◽  
P. B. Rutkevich
Keyword(s):  
Temperature Gradient ◽  
Analytical Model ◽  
Lower Boundary ◽  
Water Layer ◽  
Negative Temperature ◽  
Cloud Layer ◽  
Spatially Periodic ◽  
Typical Condition ◽  
Convective Cells ◽  
Vortex Axis

Abstract. Analytical model of convection in a thick horizontal cloud layer with free upper and lower boundaries is constructed. The cloud layer is supposed to be subjected to the Coriolis force due to the cloud rotation, which is a typical condition for tornado formation. It is obtained that convection in such system can look as just one rotating cell in contrast to the usual many-cells Benard convection. The tornado-type vortex is different from spatially periodic convective cells because their amplitudes vanish with distance from the vortex axis. The lower boundary at this convection can substantially move out of the initially horizontal cloud layer forming a single vertical vortex with intense upward and downward flows. The results are also applicable to convection in water layer with negative temperature gradient.

Risiko-Identifikation

2016 ◽  
Vol 57 (1) ◽  
pp. 15-20
Author(s):  
Armin Töpfer ◽  
Anne Maertins ◽  
Patrick Pirl
Keyword(s):  
Risk Management ◽  
Critical Factor ◽  
Risk Identification ◽  
Annual Reports ◽  
Second Step ◽  
Management Process ◽  
The Third ◽  
Risk Management Process

Ein kritischer Erfolgsfaktor des Risikomanagement-Prozesses ist die vollständige Identifikation aller maßgeblichen Risiken, wobei diejenigen Risiken mit einem hohen Impact für das Unternehmen oftmals am schwersten zu erkennen sind. Um die Risiko-Identifikation insbesondere für kleine und mittelständische Unternehmen effizienter und effektiver zu gestalten, wurde ein Raster dafür entwickelt. Im ersten Schritt wurden dazu die bestehenden Risikokategorisierungen der Literatur und im zweiten Schritt die Lageberichte der 50 SDAX-Unternehmen im Hinblick auf die enthaltenen, weil genannten Risikofelder analysiert. Diese Ergebnisse wurden im dritten Schritt sprichwörtlich übereinander geklappt, um so ein möglichst vollständiges Raster zur Risiko-Identifikation zu entwickeln. A critical factor in the risk management process is the identification of all significant risks. In order for SMEs to efficiently and effectively outline potential concerns, a grid for risk identification was developed. The first step utilized the existing risk categorisations in literature while the second step analyzed the annual reports of the 50 SDAX companies. These results were then literally folded over one another in the third step in order to achieve a more or less complete grid of relevant risks for the time being. Keywords: sdax unternehmen, rm prozess, risikokategorisierung, kmu

scholarly journals MITOS RADHIN SAGHÂRÂ DALAM KAJIAN STRUKTURALISME LEVI-STRAUSS

2018 ◽  
Vol 18 (2) ◽  
pp. 41
Author(s):  
Dewi Angelina
Keyword(s):  
Analytical Model ◽  
Traditional Healing ◽  
The Other ◽  
Second Step ◽  
Black And White

Levi-Strauss's the theory of structuralism is used as an analytical model to interpret the myth of Radhin Sahgârâ. Using this theory, there are two steps to analyze the structure of the myth. The first step, to find mytheme-mytheme in myth.In the second step, there are some figures who have an important role in the life of the community at that time, and it influenced some Madurese beliefs today. The role of Kè Polèng for Madurese, especially in Pamekasan area is a mantra for traditional healing media.Kè Polèng is believed the character that adapted the Bima's character. So, the batik craftsmen call the batik with the black-and-white characteristic as Bâtè’ Polèng. Besides, the other example that related with the myth of Radhin Saghârâis a prohibition for the fisherman to catch andkill the dolphin. The belief that is still practiced by the Madurese is a form of sacred tribute to the myths in Madura.   Keyword: myth, Madurese culture, Levi-Strauss’ Structuralism.

scholarly journals Fabrication, response and stability of miniature piezoresistive force-sensing thick-film cantilevers

2016 ◽  
Vol 2016 (CICMT) ◽  
pp. 000024-000031
Author(s):  
Thomas Maeder ◽  
Caroline Jacq ◽  
Stefane Caseiro ◽  
Peter Ryser
Keyword(s):  
Thick Film ◽  
Low Cost ◽  
Substrate Material ◽  
Force Sensing ◽  
Second Step ◽  
Ceramic Substrates ◽  
Plastic Deformations ◽  
Self Heating ◽  
Signal Drift ◽  
Micro Cracks

Abstract Miniature ceramic cantilevers have been successfully applied to the fabrication of simple and low-cost piezoresistive thick-film force-sensing cells, using different thick-film and LTCC (low-temperature co-fired ceramic) substrates. The availability of thin substrates for some materials allows much improved sensitivity compared to classical thick-film technology, with LTCC also featuring rather low substrate elastic modulus and fine structurability. However, practical applicability may be hindered by processing difficulties, such as printing and handling very thin fired substrates, or, in the case of co-fired tapes, warpage during firing. Also, signal drift is observed with some devices. In this work, we show that most of the previously-observed signal drift in some LTCC sensors is not due to self-heating, and therefore stems from defects such as micro-cracks within the ceramic cantilevers or plastic deformations in internal conductors. In a second step, we explore manufacturability of thick-film cantilevers on very thin substrates, and show that it is possible to print a single-sided design on substrates with thickness as low as 45 μm, although a lower limit of ~100 μm, depending on substrate material, is more practical.

A Dome Shaped PVDF Loudspeaker Model

2011 ◽  
Vol 97 (5) ◽  
pp. 800-808 ◽  
Author(s):  
B. Gazengel ◽  
P. Hamery ◽  
P. Lotton ◽  
A. Ritty
Keyword(s):  
Dynamic Behavior ◽  
Analytical Model ◽  
Cylindrical Cavity ◽  
Theoretical Description ◽  
Differential Pressure ◽  
Second Step ◽  
Circular Membrane ◽  
Static Behavior ◽  
Dome Shape ◽  
Theoretical Results

An analytical model is developed that describes the behavior of a dome-shaped piezoelectric loudspeaker. The loudspeaker consists of a PVDF circular membrane coupled with a rear cylindrical cavity. The dome shape is obtained by means of a static differential pressure held between the two faces of the membrane. The theoretical description of the transducer's behavior is conducted in two steps. In the first step, the static behavior of the membrane is studied in order to obtain the profile of the membrane when submitted to a static differential pressure. In the second step, the dynamic behavior of the membrane is studied. Finally, the theoretical results obtained are compared with experiments in order to evaluate the accuracy of the model.

scholarly journals Validating performance based critical actions in a high tech start-up

2014 ◽  
Vol 5 (1) ◽  
pp. 74-86
Author(s):  
Veli-Pekka Vuoti ◽  
Josu Takala ◽  
Alexander Mäntylä ◽  
Yang Liu ◽  
Wenshan Yang ◽  
...  
Keyword(s):  
Analytical Model ◽  
Future Orientation ◽  
Critical Factor ◽  
High Tech ◽  
The Past ◽  
Model Based ◽  
Start Up ◽  
Factor Index ◽  
Strategy Types ◽  
Management Groups

Abstract The objective of this study is to analyze a Finnish manufacturing case company’s operational competitiveness. A proposed analytical model based on analyses the corresponding angles of the strategic triangles (Prospector, Analyzer, and Defender). The model compares the angle differences between the strategy and resource triangles with opinions from different management groups of informants. It was found out that Normalized Scaled Critical Factor Index (NSCFI) model is more scientific comparing to formal ones through validation. Calculations based on the MSI questionnaire resulted in medium high values for the Prospector strategy both for past- and future orientation. S&R calculations regarding the past orientation resulted in low values for all strategy types, except P-NSCFI for Analyzer. Moreover this study covers a case, in where Balanced Critical Factor Index (BCFI) was used defining company annual strategy plan.

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