scholarly journals Effects of the Extrusion Process Parameter

2011 ◽  
Vol 8 (1) ◽  
pp. 65-74
Author(s):  
Prashant Baredar ◽  
Jitendra Kumar ◽  
Anil Kumar ◽  
Shankar Kumar
Keyword(s):  
Plastic Deformation ◽  
Cross Section ◽  
Cross Sections ◽  
Metal Forming ◽  
Extrusion Process ◽  
Cross Sectional ◽  
High Deformation ◽  
Tensile Forces ◽  
Cross Sectional Profile ◽  
Sectional Profile

Extrusion is an important Metal forming operation. It is a manufacturing process used to create long objects of a fixed cross sectional profile. The extrusion process is based on the plastic deformation of a material due to compressive and shears forces only. No tensile forces are applied to the extruded metal. The latter allows the material to withstand high deformation without tearing out the material. Basically, this procedure is based on the reducing and shaping the cross section of piece of metal squeezing the material through an orifice or a die. Typically the blocks of metal used for this procedure are long straight parts with circular cross sections.

scholarly journals Influence of Geometric Parameters on Aerodynamic and Acoustic Performances of Bladeless Fans

2019 ◽  
Author(s):  
Ang Li ◽  
Jun Chen ◽  
Yangfan Liu ◽  
Stuart Bolton ◽  
Patricia Davies
Keyword(s):  
Cross Section ◽  
Fluid Dynamic ◽  
Geometric Parameters ◽  
Design Stage ◽  
Air Velocity ◽  
Cross Sectional ◽  
Future Design ◽  
Cross Sectional Profile ◽  
The Cross ◽  
Sectional Profile

Abstract In recent years, the bladeless fan that does not have visible impellers have been widely applied in household appliances. Since the customers are particularly sensitive to noise and the strength of wind generated by the fan, the aerodynamic and acoustic performances of the fan need to be accurately characterized in the design stage. In this study, computational fluid dynamic (CFD) and computational aeroacoustics (CAA) are applied to investigate the performances of different designs of a bladeless fan model. The influence of four parameters, namely the airfoil selection for cross-section of the wind channel, the slit width, the height of cross-section and the location of the slit, is investigated. The results indicate the streamwise air velocity increases significantly by narrowing the outlet, but the noise level increases simultaneously. In addition, the generated noise increases while the height of fan cross-section increases, and a 4mm height of the cross section is optimal for aerodynamic performance. When the slit is closer to the location of maximum thickness, the performances of the bladeless fan increases. Moreover, the performance is not changed significantly by changing the cross-sectional profile. Finally, the optimal geometric parameters are identified to guide the future design of the bladeless fan.

Twisting and Bending of Thin-Walled Prismatic Beams of Open Cross-Sectional Profile

1970 ◽  
Vol 12 (2) ◽  
pp. 130-134 ◽  
Author(s):  
T. Harrison
Keyword(s):  
Cross Sections ◽  
Virtual Work ◽  
Cross Sectional ◽  
Transverse Bending ◽  
Prismatic Beam ◽  
Loading System ◽  
Cross Sectional Profile ◽  
Thin Walled ◽  
Sectional Profile ◽  
Principle Of Virtual Displacements

Previous studies of the behaviour, in generalized co-ordinates, of thin-walled, prismatic beams of open cross-sectional profile have included, explicitly, only the effects of distributed transverse forces, q x and q y, distributed longitudinal forces, q z, and distributed torsional couples, m z. Using the principle of virtual displacements, the work of previous investigators is extended to include, quite generally, the effects of the hitherto neglected distributed couples, m x and m y. The derivation of the differential equation relating to the twisting of an open-section prismatic beam is presented fully whilst those relating to transverse and axial displacements of cross-sections are merely stated. The kinematic and static boundary conditions for a cantilever are also established from the virtual work equations. These show that the free-end shear boundary condition associated with transverse bending which is usually adopted in engineering calculations is inadequate for such a generalized loading system.

Assessment of the actual shape of the hot-rolled strip cross-section contour. Part 2. Profile Classifier

2020 ◽  
pp. 33-37
Author(s):  
S. M. Belskiy ◽  
◽  
A. N. Shkarin ◽  
V. A. Pimenov ◽  
◽  
...  
Keyword(s):  
Cross Section ◽  
Middle Part ◽  
Characteristic Classes ◽  
Rolled Strip ◽  
Cross Sectional ◽  
Hot Rolled Strip ◽  
Cross Sectional Profile ◽  
Cold Rolled ◽  
Sectional Profile ◽  
Hot Rolled

The geometric parameters describing the features of the crosssectional profile of a hot-rolled strips do not give a complete picture of the flatness acquired by the cold-rolled strips rolled from these strips. An additional analysis, the results of which are presented in Message 1, showed that there are four characteristic classes of cross-sectional profiles of hot rolled strips that have a significant effect on the shape of the strips during cold rolling, three of which negatively affect the flatness of the cold rolled strips. The cross-sectional profiles of hot-rolled strips with a concave middle part and / or marginal thickenings lead to the appearance of edge waviness, peak-like cross-sectional profiles cause central warping. Therefore, the actual task is to determine the factual shape of cross-sectional profile. 6th order polynomials were used to digitalize and parameterize hot-rolled profile. As a result, we developed analytic function of the transverse profile, which keeps important information about its near-edge areas and features in the middle part. To assign a specific crosssectional profile of a hot-rolled strip to one of four characteristic classes of cross-sections, mathematical software was developed, called a classifier, and implemented with the programming environment R. To classify the profiles of the hot-rolled cross-section according to characteristic classes, a linear discriminant method was used as a machine learning method analysis. The result is an adequate mathematical model for recognizing the shape of the cross-sectional profile. The study was carried out with the financial support of the Russian Foundation for Basic Research within the framework of scientific project No. 19-38-90257.

Rapid motions of free-surface avalanches down curved and twisted channels and their numerical simulation

2005 ◽  
Vol 363 (1832) ◽  
pp. 1551-1571 ◽  
Author(s):  
Shiva P Pudasaini ◽  
Yongqi Wang ◽  
Kolumban Hutter
Keyword(s):  
Numerical Simulation ◽  
Cross Section ◽  
Circular Cross Section ◽  
Hyperbolic Partial Differential Equations ◽  
Finite Mass ◽  
Governing Equations ◽  
Cross Sectional ◽  
Variation Diminishing ◽  
Cross Sectional Profile ◽  
Sectional Profile

This paper presents a new model and discussions about the motion of avalanches from initiation to run-out over moderately curved and twisted channels of complicated topography and its numerical simulations. The model is a generalization of a well established and widely used depth-averaged avalanche model of Savage & Hutter and is published with all its details in Pudasaini & Hutter (Pudasaini & Hutter 2003 J. Fluid Mech. 495 , 193–208). The intention was to be able to describe the flow of a finite mass of snow, gravel, debris or mud, down a curved and twisted corrie of nearly arbitrary cross-sectional profile. The governing equations for the distribution of the avalanche thickness and the topography-parallel depth-averaged velocity components are a set of hyperbolic partial differential equations. They are solved for different topographic configurations, from simple to complex, by applying a high-resolution non-oscillatory central differencing scheme with total variation diminishing limiter. Here we apply the model to a channel with circular cross-section and helical talweg that merges into a horizontal channel which may or may not become flat in cross-section. We show that run-out position and geometry depend strongly on the curvature and twist of the talweg and cross-sectional geometry of the channel, and how the topography is shaped close to run-out zones.

scholarly journals Cause of Angular Distortion in Fusion Welding: Asymmetric Cross-Sectional Profile along Thickness

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 58 ◽  
Author(s):  
Deqiao Xie ◽  
Jianfeng Zhao ◽  
Huixin Liang ◽  
Shuang Liu ◽  
Zongjun Tian ◽  
...  
Keyword(s):  
Cross Section ◽  
Fusion Welding ◽  
Angular Distortion ◽  
Cross Sectional ◽  
Section Profile ◽  
Cross Sectional Profile ◽  
The Asymmetry ◽  
The Difference ◽  
Sectional Profile ◽  
Cross Section Profile

Angular distortion is a common problem in fusion welding, especially when it comes to thick plates. Despite the fact that various processes and influencing factors have been discussed, the cause of the angular distortion has not been clearly revealed. In this research, the asymmetry of cross-sectional profile along thickness is considered of great importance to the angular distortion. A theoretical model concerning the melting-solidification process in fusion welding was established. An expression of the angular distortion was formulated and then validated by experiments of laser welding 316L stainless steel. The results show that the asymmetric cross-sectional profile is a major contributory factor towards the angular distortion mechanism. The asymmetry of cross-section profile along thickness causes the difference between two bending moments in the lower and upper parts of the joint. This is the difference that drives the angular distortion of the welded part. Besides, the asymmetry of cross-section profile is likely to be influenced by various processes and parameters, thereby changing the angular distortion.

Topology Synthesis of Extrusion-Based Nonlinear Transient Designs

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Neal M. Patel ◽  
Charles L. Penninger ◽  
John E. Renaud
Keyword(s):  
Cross Section ◽  
Three Dimensional ◽  
Optimization Methods ◽  
Constant Cross Section ◽  
Cross Sectional ◽  
Design Concepts ◽  
Nonlinear Transient ◽  
Cross Sectional Profile ◽  
Sectional Profile ◽  
Finishing Processes

Many practical structural designs require that the structure is easily manufactured. Design concepts synthesized using conventional topology optimization methods are typically not easily manufactured, in that multiple finishing processes are required to construct the component. A manufacturing technique that requires only minimal effort is extrusion. Extrusion is a manufacturing process used to create objects of a fixed cross-sectional profile. The result of using this process is lower costs for the manufacture of the final product. In this paper, a hybrid cellular automaton algorithm is developed to synthesize constant cross section structures that are subjected to nonlinear transient loading. The novelty of the proposed method is the ability to generate constant cross section topologies for plastic-dynamic problems since the issue of complex gradients can be avoided. This methodology is applied to extrusions with a curved sweep along the direction of extrusion as well. Three-dimensional examples are presented to demonstrate the efficiency of the proposed methodology in synthesizing these structures. Both static and dynamic loading cases are studied.

scholarly journals Cutting the first ‘teeth’: a new approach to functional analysis of conodont elements

2013 ◽  
Vol 280 (1768) ◽  
pp. 20131524 ◽  
Author(s):  
Duncan J. E. Murdock ◽  
Ivan J. Sansom ◽  
Philip C. J. Donoghue
Keyword(s):  
Functional Analysis ◽  
Cross Sections ◽  
Functional Performance ◽  
Individual Element ◽  
Cross Sectional ◽  
New Approach ◽  
Functional Models ◽  
Cross Sectional Profile ◽  
Tomographic Data ◽  
Sectional Profile

The morphological disparity of conodont elements rivals the dentition of all other vertebrates, yet relatively little is known about their functional diversity. Nevertheless, conodonts are an invaluable resource for testing the generality of functional principles derived from vertebrate teeth, and for exploring convergence in a range of food-processing structures. In a few derived conodont taxa, occlusal patterns have been used to derive functional models. However, conodont elements commonly and primitively exhibit comparatively simple coniform morphologies, functional analysis of which has not progressed much beyond speculation based on analogy. We have generated high-resolution tomographic data for each morphotype of the coniform conodont Panderodus acostatus . Using virtual cross sections, it has been possible to characterize changes in physical properties associated with individual element morphology. Subtle changes in cross-sectional profile have profound implications for the functional performance of individual elements and the apparatus as a whole. This study has implications beyond the ecology of a single conodont taxon. It provides a basis for reinterpreting coniform conodont taxonomy (which is based heavily on cross-sectional profiles), in terms of functional performance and ecology, shedding new light on the conodont fossil record. This technique can also be applied to more derived conodont morphologies, as well as analogous dentitions in other vertebrates and invertebrates.

Assessment of surface wear properties with initial macro crack defects using on-line visual ferrography and SEM methods

2015 ◽  
Vol 67 (6) ◽  
pp. 538-548 ◽  
Author(s):  
Wei Yuan ◽  
K. S. Chin ◽  
Guangneng Dong ◽  
Meng Hua
Keyword(s):  
Plastic Deformation ◽  
Wear Behavior ◽  
Surface Wear ◽  
Wear Properties ◽  
Coverage Area ◽  
Cross Sectional ◽  
Content Type ◽  
Cross Sectional Profile ◽  
On Line ◽  
Sectional Profile

Purpose – This paper aims to optimize the operating condition of mechanical parts, whose working surfaces have macro-crack defects, and surface wear properties with macro-cracks are assessed through experimental investigation. Design/methodology/approach – Macro-cracks perpendicular to the direction of sliding were manufactured on discs by electric discharge machining. Tribological tests under oil lubrication were conducted on a ball-on-disc test rig. Their wear processes were monitored with on-line visual ferrography. The cross-sectional profile and morphology of the wear track were analyzed using a T200 profilometer and a scanning electron microscope, respectively. Effects of different crack numbers and various applied normal loads on the wear behavior were studied. Findings – The macro-cracks tend to promote plastic deformation on the contact disc surfaces, and material plastic deformation of the crack edges varies with the magnitude of applied normal loads. Relationship of the duration of running-in period and root mean square index of the particle coverage area with the numbers of crack is approximately linear. Originality/value – The wear properties of surfaces with macro-cracks were assessed with various crack numbers and with different applied normal loads, and the relationship between the index of particle coverage area and the wear rate was established.

scholarly journals Metal Forming of Lightweight Magnesium Alloys for Aviation Applications

2017 ◽  
Vol 62 (3) ◽  
pp. 1559-1566 ◽  
Author(s):  
R.E. Śliwa ◽  
T. Balawender ◽  
E. Hadasik ◽  
D. Kuc ◽  
A. Gontarz ◽  
...  
Keyword(s):  
Magnesium Alloys ◽  
Cross Sections ◽  
Metal Forming ◽  
Extrusion Process ◽  
Technological Parameters ◽  
Initial State ◽  
Cross Sectional ◽  
Complex Cross ◽  
Upsetting Test ◽  
Specific Profile

AbstractThe work presents an analysis of selected magnesium alloys as structural materials to be used in production of aircraft parts as well as their technological parameters in some manufacturing processes. Upsetting test, backward extrusion and Kobo extrusion of complex cross-sectional profiles and forging process were realized using magnesium alloys AZ31, AZ61, AZ80, WE 43 and Mg alloy with Li for production of thin - walled aircraft profiles and forged aviation parts. The range of temperatures and extrusion rate for the manufacturing these profiles were determined. Tests also covered the analysis of microstructure of Mg alloys in the initial state as well as after the extrusion process. It has been proved that the proper choice of parameters in the case of a specific profile extruded from magnesium alloys allows the manufacturing of products of complex cross-sections and the quality required in aerospace industry. This has been demonstrated on the examples of complex cross-sectional profiles using elements of varied wall thickness and examples of forged aviation parts: aircraft wheel hub and helicopter lever for control system.

X-Ray Replication of Submicrometer Linewidth Patterns

1977 ◽  
Vol 35 ◽  
pp. 136-137
Author(s):  
Henry I. Smith ◽  
D.C. Flanders
Keyword(s):  
Electron Beam Lithography ◽  
Cross Sectional ◽  
X Ray ◽  
Electron Backscattering ◽  
Spatial Frequencies ◽  
Cross Sectional Profile ◽  
Carbon Foils ◽  
Sectional Profile ◽  
And Control ◽  
Soft Radiation

Scanning electron beam lithography has been used for a number of years to write submicrometer linewidth patterns in radiation sensitive films (resist films) on substrates. On semi-infinite substrates, electron backscattering severely limits the exposure latitude and control of cross-sectional profile for patterns having fundamental spatial frequencies below about 4000 Å(l),Recently, STEM'S have been used to write patterns with linewidths below 100 Å. To avoid the detrimental effects of electron backscattering however, the substrates had to be carbon foils about 100 Å thick (2,3). X-ray lithography using the very soft radiation in the range 10 - 50 Å avoids the problem of backscattering and thus permits one to replicate on semi-infinite substrates patterns with linewidths of the order of 1000 Å and less, and in addition provides means for controlling cross-sectional profiles. X-radiation in the range 4-10 Å on the other hand is appropriate for replicating patterns in the linewidth range above about 3000 Å, and thus is most appropriate for microelectronic applications (4 - 6).

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