Analytical modeling and dimensionless characteristics of open wet clutches in consideration of gravity

Wet clutches are widely used in power transmission, but lack of the fact of an energy loss in open state condition. The flow conditions in the fluid flow of an open wet clutches are analyzed by analytical means. The requisite simplifications that result in an analytically integrateable solution are stated in detail. Special emphasis is put on the role of gravitation in the equations of fluid motion. This force component leads to a slightly earlier aeration than stated in earlier conditions. The simplifications and the resultant solutions are considered by means of dimensionless quantities. Despite the actual geometric parameters the drag torque can be described as $$\zeta_{\mathrm{m}}=\pi/\mathrm{Re}_{\mathrm{l}}$$ ζ m = π / Re l . An additional aeration condition is introduced, which is based on the back flow of the radial velocity. This quantity can be described as non-dimensional volumetric flow rate $$Q^{*}$$ Q * . With these equations at hand the theoretical considerations are transferred to an evaluation with grooves, where a backward curved groove appears as beneficial for further investigations.

The Reduction of Force Component Produced by Short Sides by Analyzing the Corner of Coil in Planar Motor with Halbach Magnet Array

The planar motor with moving-magnet is purely levitated by the stator coils. The forces produced by coils are calculated with the analytical model of magnet array and coil surface model for applying to the real time control. Take the coil and the Halbach magnet array which is at 45 degree with the long side of coil for analysis. The force component produced by short sides can be eliminated for conveniently controlling when the length of coil takes certain dimension. In practice, the force component produced by short sides is small but not zero. There are two reasons, one is the higher harmonics and the other is the corner segments of coil. The force integral expressions of coil corner segments are given by the Lorenz force law. Then the forces numerically calculated with harmonic model and coil full model are verified by comparing with the magnetic surface charge model and finite element model. In order to reduce the force component produced by short sides, the different corners of coil are analyzed. Comparing the forces of different corners of coil, the force component produced by short sides can be significantly reduced with slightly change of the other force components.

PROBLEM OF THE COSMIC GRAVITY MEASUREMENT

Based on Newton's adapted law of universal gravitation in the case of moving masses, taking into account the finite velocity of gravity, differential equations of motion of celestial bodies are obtained. The transient process of the precession of the planet's perihelion was simulated for the first time. A new physical interpretation of the celestial phenomenon due to the discovered new component of force in addition to the Newtonian and Lorentz (gravitomagnetic) is given. The problem of measuring a new force has been formed. The results of computer simulation of the precessing perihelion of the planet considering a new force component are discussed.

Influence of fibre orientation on cutting force in up and down milling of UD-CFRP composites

Machining of carbon fibre reinforced polymer (CFRP) composites is extremely difficult, mainly due to their inhomogeneous and anisotropic properties. Predicting of cutting force during machining of CFRP is also difficult because the machinability properties of the composite are significantly orientation-dependent (fibre and machining directions). The main objective of the present study is to analyse the influence of fibre orientation on cutting force in milling of unidirectional CFRP. Up and down milling experiences were conducted based on a full factorial design. Experimental data were processed by fast Fourier transformation, regression analysis, and graphical adequate analysis. Multiple-order polynomial models were developed in order to minimise cutting force. Experimental results show that fibre orientation angle significantly influences the cutting force; furthermore, it does not have a significant effect on the passive force component, while the radial force component is more sensitive to the fibre orientation at up milling, than at down milling. An optimal condition is recommended for zig-zag milling of unidirectional CFRPs.

Improved K-medoids algorithm-based clustering analysis for handle driving force in automotive manual sliding door closing process

Handle driving forces are the input of the automotive sliding door dynamic system and play an important role for ensuring a smooth closing process during manual sliding door mechanism design. It is important to provide a reliable and accurate input for the manual sliding door mechanism during the design and analysis stage. This paper aims to present an improved K-medoids clustering algorithm to investigate the characteristic of handle driving forces in manually closing an automotive sliding door based on experimental data. The improved K-medoids clustering algorithm includes two stages: observation-based clustering stage and traditional K-medoids clustering stage. In all, 134 subjects have been recruited to manually close the sliding door in the lab and the handle driving force data are collected and processed. The handle driving forces are described in the sliding door coordinate system (XYZ) fixed on the door. This study mainly focuses on the X direction force component clustering analysis. The first stage of the improved algorithm classifies the X direction force components into three clusters based on force curve shapes. Then, each of the above identified three clusters is clustered with the traditional K-medoids clustering algorithm. Results show that the X direction force component has three different shapes: Shape 1—only one crest in the curve, Shape 2—two crests in the curve, and Shape 3—one crest and one trough in the curve. The forces with three different shapes are finally divided into six clusters and the amplitude and time duration are similar for X direction forces within the same cluster and are different in the different clusters. The medoids of these clusters are the mined representative prototypes. Compared to the pure traditional K-medoids algorithm, the improved algorithm can provide much better results that give insights on subjects’ door closing behaviors.

Contrasting Age Effects on Complexity of Tracking Force and Force Fluctuations During Monorhythmic Contraction

This study contrasted the stochastic force component between young and older adults, who performed pursuit tracking/compensatory tracking by exerting in-phase/antiphase forces to match a sinusoidal target. Tracking force was decomposed into the force component containing the target frequency and the nontarget force fluctuations (stochastic component). Older adults with inferior task performance had higher complexity (entropy across time; p = .005) in total force. For older adults, task errors were negatively correlated with force fluctuation complexity (pursuit tracking: r = −.527 to −.551; compensatory tracking: r = −.626 to −.750). Notwithstanding an age-related increase in total force complexity (p = .004), older adults exhibited lower complexity of the stochastic force component than young adults did (low frequency: p = .017; high frequency: p = .035). Those older adults with a higher complexity of stochastic force had better task performance due to the underlying use of a richer gradation strategy to compensate for impaired oscillatory control.

Influence of the multi-component electrical feed of air-core industrial reactors on their sound radiation

High voltage devices such as dry-type air-core reactors are subjected to environmental noise standards. Their excitation is due to Lorentz forces originated from the magnetic field, created by the coil itself, combined with the feed current. The objective of this paper is to show how spectral components present in the supply current of industrial dry-type air-core reactors is likely to produce a significant acoustic radiation. First, the multi-component distribution of the Lorentz forces is established. Then, the multi-physics computation process allowing to determine the acoustic pressure induced by each force component is presented. Finally, two industrial reactors are studied: a single and a multi-layer coil. It is pointed out that significant acoustic emergence can be induced by the interaction between small current spectral components with the fundamental or with each other.

A New Approach to Prevent Crown Loosening and Caries in the AdvanSync2 Class II Corrector

The AdvanSync2 Class II corrector is a modification of the original Herbst appliance with advantages of immediate placement in conjunction with fixed appliances. Though easy to place and activate, the molar bands have a possibility of dislodgement due to the vertical force component from the telescopic arms requiring immediate intervention from the orthodontist. An easy and reliable method to prevent molar band dislodgement is highlighted.

Structuring Control of Facial Layer during Edge Cutting Machining

The article considers efficiency increase of formation of surface performance characteristics of machine components. The possibility of structuring control of facial layer on the basis of measuring of thermoelectromotive force (thermo-emf), cutting force component and also vibroacoustic signal has been scrutinized.