scholarly journals Experimental investigation of the dynamics of a slider-crank mechanism with local linear force input

2021 ◽  
pp. 1-20
Author(s):  
Jarl Beckers ◽  
Björn Verrelst ◽  
Francesco Contino ◽  
Joeri Van Mierlo
Keyword(s):  
Transient Behaviour ◽  
Actuation Force ◽  
Mechanical Structure ◽  
Bottom Dead Centre ◽  
System A ◽  
Local Linear ◽  
Mechanical Investigation ◽  
Linear Force ◽  
Crank Mechanism ◽  
Dead Centre

Abstract Conventional implementation of slider-crank mechanisms result in high loads transmitted through the mechanical structure, inhibiting the design of compact and oil-free machines. Therefore, this research proposes to step away from the conventional, i.e. rotative, actuation and to investigate local linear actuation on the slider-component directly, while maintaining the kinematic link of the slider-crank configuration. In this work the local linear actuating principle is evaluated experimentally where the goal is to obtain a continuous movement of the slider mechanism where Top Dead Centre & Bottom Dead Centre are reached and to minimise the loads transmitted through the mechanical structure. The non-isochronous transient behaviour of a slider-crank mechanism loaded with a spring-damper element is detailed as well as the optimal working conditions at steady state to achieve a reduced loading of the kinematic structure. By matching the operating frequency and resonance frequency of the system, a reduction of the loads transmitted through the system by 63% of the nominal spring load can be achieved. Further experimental (and multibody mechanical) investigation on the influence of flywheel exposes a clear trade-off between the sensitivity of the system and the transmission of the actuation force through the kinematic link.

scholarly journals Numerical modelling of a fast-flowing outlet glacier: experiments with different basal conditions

1996 ◽  
Vol 23 ◽  
pp. 237-246 ◽  
Author(s):  
Frank Pattyn
Keyword(s):  
Deformation Process ◽  
Drainage Basin ◽  
Ice Sheet ◽  
Outlet Glacier ◽  
Transient Behaviour ◽  
Cyclic Behaviour ◽  
System A ◽  
Basal Ice ◽  
Equal Importance ◽  
Fully Coupled

Recent observations in Shirase Drainage Basin. Enderby Land, Antarctica, show that the ice sheet is thinning at the considerable rate of 0.5–1.0 m a −1. Surface velocities in the stream area reach more than 2000 ma−1, making Shirase Glacier one of the fastest-flowing glaciers in East Antarctica. A numerical investigation of the present stress field in Shirase Glacier shows the existence of a large transition zone 200 km in length where both shearing and stretching are of equal importance, followed by a stream zone of approximately 50 km, where stretching is the major deformation process.In order to improve insight into the present transient behaviour of the ice-sheet system, a two-dimensional time-dependent flowline model has been developed, taking into account the ice-stream mechanics. Both bedrock adjustment and ice temperature are taken into account and the temperature field is fully coupled to the ice-sheet velocity field.Experiments were carried out with different basal motion conditions in order to understand their influence on the dynamic behaviour of the ice sheet and the stream area in particular. Results revealed that when basal motion becomes the dominant deformation process, (partial) disintegration of the ice sheet is counteracted by colder basal-ice temperatures due to higher advection rates. This gives rise to a cyclic behaviour in ice-sheets response and large changes in local imbalance values.

scholarly journals Force-Free Models of Filament Channels

1998 ◽  
Vol 167 ◽  
pp. 274-277
Author(s):  
A.W. Longbottom
Keyword(s):  
Magnetic Fields ◽  
Multigrid Method ◽  
Flux Distribution ◽  
Free Field ◽  
Idealized Model ◽  
System A ◽  
Filament Channel ◽  
Linear Force ◽  
Field Lines ◽  
Force Free Field

AbstractA fast multigrid method to calculate the linear force-free field for a prescribed photospheric flux distribution is outlined. This is used to examine an idealized model of a filament channel. The magnetic fields, for a number of different field strengths and positions, are calculated and the height up to which field lines connect along the channel is examined. This is shown to strongly depend on the value of the helicity of the system. A possible explanation, in terms of the global helicity of the system, is suggested for the dextral/sinistral hemispheric pattern observed in filament channels.

scholarly journals Dynamic Modeling and Simulation of a Stand-alone DC Hybrid Microgrid for a Base Transceiver Station in Nigeria

2021 ◽  
Vol 5 (2) ◽  
pp. 41-49
Author(s):  
Cyprian Oton ◽  
M. Tariq Iqbal
Keyword(s):  
Modeling And Simulation ◽  
Dynamic Modeling ◽  
Storage System ◽  
Buck Converter ◽  
Solar Irradiation ◽  
Solar Array ◽  
Diesel Generator ◽  
Transient Behaviour ◽  
System A ◽  
Base Transceiver Station

This work considers the dynamic modeling and simulation of a DC hybrid power system for a rural base transceiver station in Nigeria currently being powered by an AC diesel generator (DG). The transient behaviour of the system is studied under varying solar irradiation to ascertain the stability of the power supplied to the sensitive telecommunication equipment. Each component of the system is designed and simulated in a MATLAB/Simulink environment and connected to form the whole system. A permanent Magnet DC diesel generator is used as back-up power for the system. A detailed presentation of the solar array, buck converter, battery storage system, battery controller, diesel generator and the load are presented in this paper. The result shows a stable power output to the load at rated voltage of 48 V.

scholarly journals Numerical modelling of a fast-flowing outlet glacier: experiments with different basal conditions

1996 ◽  
Vol 23 ◽  
pp. 237-246 ◽  
Author(s):  
Frank Pattyn
Keyword(s):  
Deformation Process ◽  
Drainage Basin ◽  
Ice Sheet ◽  
Outlet Glacier ◽  
Transient Behaviour ◽  
Cyclic Behaviour ◽  
System A ◽  
Basal Ice ◽  
Equal Importance ◽  
Fully Coupled

Recent observations in Shirase Drainage Basin. Enderby Land, Antarctica, show that the ice sheet is thinning at the considerable rate of 0.5–1.0 m a−1. Surface velocities in the stream area reach more than 2000 ma−1, making Shirase Glacier one of the fastest-flowing glaciers in East Antarctica. A numerical investigation of the present stress field in Shirase Glacier shows the existence of a large transition zone 200 km in length where both shearing and stretching are of equal importance, followed by a stream zone of approximately 50 km, where stretching is the major deformation process.In order to improve insight into the present transient behaviour of the ice-sheet system, a two-dimensional time-dependent flowline model has been developed, taking into account the ice-stream mechanics. Both bedrock adjustment and ice temperature are taken into account and the temperature field is fully coupled to the ice-sheet velocity field.Experiments were carried out with different basal motion conditions in order to understand their influence on the dynamic behaviour of the ice sheet and the stream area in particular. Results revealed that when basal motion becomes the dominant deformation process, (partial) disintegration of the ice sheet is counteracted by colder basal-ice temperatures due to higher advection rates. This gives rise to a cyclic behaviour in ice-sheets response and large changes in local imbalance values.

scholarly journals Reduction in holding time at bottom dead centre in hot stamping by water and die quenching

2018 ◽  
Vol 15 ◽  
pp. 1111-1118 ◽  
Author(s):  
Yuki Nakagawa ◽  
Ken-ichiro Mori ◽  
Tomoyoshi Maeno ◽  
Yoshitaka Nakao
Keyword(s):  
Hot Stamping ◽  
Holding Time ◽  
Bottom Dead Centre ◽  
Die Quenching ◽  
Dead Centre

scholarly journals Tailored Sheared Blanks Produced by Incremental ECAP

2015 ◽  
Vol 651-653 ◽  
pp. 651-656 ◽  
Author(s):  
Andrzej Rosochowski ◽  
Lech Olejnik ◽  
Malgorzata Rosochowska
Keyword(s):  
Finite Element ◽  
Equal Channel Angular Pressing ◽  
Metal Forming ◽  
Bottom Dead Centre ◽  
Varying Thickness ◽  
Angular Pressing ◽  
Bottom Position ◽  
Ultrafine Grained ◽  
Tailored Blank ◽  
Dead Centre

Incremental equal channel angular pressing (I-ECAP) is a process used for production of continuous ultrafine grained bars, plates and sheets. Normally the thickness of the processed billet is kept unchanged in consecutive passes to enable repetitive insertion into the same die. This is achieved by controlling the bottom dead centre of the reciprocating punch. However, if a final product requires being thinner and therefore longer, the bottom position of the punch can be lowered before the last pass. Going further, the bottom position of the punch can be changed during the process, which opens up a possibility to vary billet thickness along its length. Such a product, especially sheet, can serve as a preform for further metal forming operations and is known as tailored blank. This paper will show examples of varying thickness sheets produced by different configurations of I-ECAP. Experimental and finite element results will be presented.

Development of the Two-Dimensional General Mechanical CAD System

2013 ◽  
Vol 694-697 ◽  
pp. 3168-3171
Author(s):  
Yong Jun Feng
Keyword(s):  
Mechanical Structure ◽  
Standard Data ◽  
Cad System ◽  
Function Points ◽  
System A ◽  
Programme Development ◽  
The Common ◽  
Set Up ◽  
2D Drawing ◽  
Auto Cad

Although the function of Auto CAD is powerful, its professional pertinence is weak, and partuicularly it cannot satisfy the requirement for the efficient drawing and annotation of the common mechanical structure. The author of this paper has a discussion on the development principle and methods of a 2D General Mechanical CAD System (MACD). Faced up with all the requirements of the mechanical designing 2D drawing, and on the basis of the overall extracting the special features of the mechanical structure 2D primitives, the designing habits and the designing standards and specifications, all the function points of the system have been set up through the intersection and integration of the Auto CAD working mode and the functions of the system. A mechanical CAD system with a general drawing fucntion has been complished with a comprehensive use of the tools of the Auto CAD like function expansion, menu customization and programme development. Applied practice shows that this system has satisfied all the requirements for the mechanical desginers to make the drawings, annotations, enquiry for the standard data, the structure enquiry and quotations so that the designing efficiency has been greatly increased.

New Design for a Differentially Pumped Hydration Chamber for a Siemens IA

1971 ◽  
Vol 29 ◽  
pp. 44-45
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscopy ◽  
Water Vapor ◽  
Electron Diffraction ◽  
Water Vapor Pressure ◽  
Biological Materials ◽  
Thin Membrane ◽  
Reliable System ◽  
System A ◽  
Water Films ◽  
Aperture Opening

Electron microscopy and diffraction of biological materials in the hydrated state requires the construction of a chamber in which the water vapor pressure can be maintained at saturation for a given specimen temperature, while minimally affecting the normal vacuum of the remainder of the microscope column. Initial studies with chambers closed by thin membrane windows showed that at the film thicknesses required for electron diffraction at 100 KV the window failure rate was too high to give a reliable system. A single stage, differentially pumped specimen hydration chamber was constructed, consisting of two apertures (70-100μ), which eliminated the necessity of thin membrane windows. This system was used to obtain electron diffraction and electron microscopy of water droplets and thin water films. However, a period of dehydration occurred during initial pumping of the microscope column. Although rehydration occurred within five minutes, biological materials were irreversibly damaged. Another limitation of this system was that the specimen grid was clamped between the apertures, thus limiting the yield of view to the aperture opening.

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