Finite Element Magnetostatic Analysis of Magnetostrictive (Tb0.3Dy0.7Fe1.95) Actuator with Different Housing Materials

Permeability of a housing material is one of the significant factors affecting the performance of Tb0.3Dy0.7Fe1.95 based magnetostrictive actuator. According to Lenz’s law the rate of flux transfer depends on permeability of housing material surrounding the terfenol-D. In this paper the co-axial coils in a free air are analysed under direct current excitation and the results are found to agree well with both analytical and Maxwell simulation. Also, the comparison of flux density distribution in co-axial coils placed inside different housing materials of magnetostrictive actuator is found by solving magnetostatic equations using Ansoft Maxwell 2D solver. The axial distribution of magnetic flux density, radial distribution of magnetic flux density and flux distribution in the actuator assembly with different housing materials namely mild steel, cast iron and aluminium with and without Terfenol-D are discussed.Defence Science Journal, 2013, 63(4), pp.423-428, DOI:http://dx.doi.org/10.14429/dsj.63.486

Terfenol-D Layer in a Functionally Graded Pipe Transporting Fluid for Free Vibration

Knowledge of natural frequency of pipeline conveying fluid has relevance to designer to avoid failure of pipeline due to resonance. The damping characteristics of pipe material can be increased by using smart materials like magnetostrictive namely, TERFENOL-D. The objective of the present chapter is to investigate vibration and instability characteristics of functionally graded Terfenol-D layered fluid conveying pipe utilizing Terfenol-D layer as an actuator. First, the divergence of fluid conveying pipe is investigated without feedback control gain and thermal loading. Subsequently, the eigenvalue diagrams are studied to examine methodically the vibrational characteristics and possible flutter and bifurcation instabilities eventuate in different vibrational modes. Actuation of Terfenol-D layer shows improved stability condition of fluid conveying pipe with variation in feedback control gain and thermal loading. Differential quadrature and differential transform procedures are used to solve equation of motion of the problem derived based on Euler-Bernoulli beam theory. Finally, the effects of important parameters including the feedback control gain, thermal loading, inner radius of pipe and density of fluid on vibration behavior of fluid conveying pipe, are explored and presented in numerical results

Viskoznost – jednostavni kriterij pri konstruiranju kalupa za injekcijsko prešanje plastomera

Plastomeri se odlikuju ogromnim brojem varijacija različitih svojstava. Relativno se mali broj tih materijala injekcijski prešaa. Rad se bavi problemom predlaganja kriterija konstruiranja kalupa koji su neizvjesni za određenu kombinaciju svojstava materijala, specifi kaciju stroja i karakteristike kalupljenja. Imperativno obuhvaćajući njihove odnose ponašanja izveden je jedinstveni analitički konstrukcijski kriterij izravno iz prvih načela; shvaćajući uljevni sustav (e. injection conduit) prema kapilarnoj cijevi; kao i poznavajući generaliziran Newtonov koncept za plastomerne taljevine opisan reološkim zakonom potencija.. Budući da je jednostavan, predloženi kriterij se lako prihvaća u samoj ranoj fazi konstrukcije kalupa i obuhvaća puni raspon plastomernih in-situ stanja. Stoga se svaki plastomer može injekcijski prešati samo ako su odgovarajući dobavni sustav zavisno konstruiran. Kako bi se razjasnila ta činjenica primijenila se hipotetička intervencija kako bi se stalno senzibilizirali svi plastomeri. Pri tome jasno objašnjavajući zašto odgovor kalupne šupljine na tečenje taljevine nikada ne može biti ispravljen, čak i nakon velikog broja promjene parametara procesa. Na kraju, rad se proširuje na ono što se prije smatralo linearnim odnosom veličine dobavnog voda uljevnog kanala prema in-situ stanju taljevine uspoređujući izravnu eksponencijalnu proporcionalnost s diskretnim nagibom i visinom za svako ponašanje plastomera.Thermoplastics are available in abundance with immense properties variations, but only few are processed by injection moulding. So this manuscript deals with this issue by proposing a design criteria contingent to a particular combination of material properties, machine specifi cations and moulding features. Pertinently embracing their behavioural relationships a unique analytical design criterion was deduced directly from fi rst principles. Comprehending injection conduit to an analogous capillary tube; as well as cognising generalized Newtonian concept for thermoplastic melts with power-law description of in-situ rheological behaviour. The proposed criterion being simple and generic easily adapts in early mould design itself and comprehends entire range of thermoplastic in-situates. Hereafter any thermoplastics could be injection moulded by contingently designing an exclusive mould feed system for it. This percipience was elucidated by continuously sensitising a hypothetical intervene across all thermoplastics while explicitly appraising, why melt kinesis lacunae can never be fully rectifi ed, despite manipulating process parameters many times? Finally, the manuscript extends hereto-believed linear relationship between runner-conduit size and in-situ melt state to direct exponential proportionality with discrete slope and altitude for each thermoplastic behaviour

Thermal induced motion of functionally graded beams subjected to surface heating

Thin beam of the functionally graded (FG) type subjected to a step heat input on one surface and insulated or exposed to convective heat loss on the opposite surface is under consideration for the evaluation of thermal induced motion. The dynamic displacement and dynamic thermal moment of the beam are analysed when the temperature gradient is independent of the beam displacement. The power law index dictates the metal–ceramic distribution across thickness of the beam and its effect on the thermal vibration of the beam is examined. The article discusses, in depth, the influence of various factors such as length to thickness ratio of beam, heat transfer boundary conditions, physical boundary conditions, and metal–ceramic combination on the thermal oscillations of FG beam. It is found that attenuation of the amplitude of static thermal deflection and superimposed thermal oscillations is a strong function of the metal–ceramic combination for the FG beam

Computational design of mould sprue for injection moulding thermoplastics

To injection mould polymers, designing mould is a key task involving several critical decisions with direct implications to yield quality, productivity and frugality. One prominent decision among them is specifying sprue-bush conduit expansion as it significantly influences overall injection moulding; abstruseness anguish in its design criteria deceives direct determination. Intuitively designers decide it wisely and then exasperate by optimising or manipulating processing parameters. To overwhelm that anomaly this research aims at proposing an ideal design criteria holistically for all polymeric materials also tend as a functional assessment metric towards perfection i.e., criteria to specify sprue conduit size before mould development. Accordingly, a priori analytical criterion was deduced quantitatively as expansion ratio from ubiquitous empirical relationships specifically a.k.a an exclusive expansion angle imperatively configured for injectant properties. Its computational intelligence advantage was leveraged to augment functionality of perfectly injecting into an impression gap, while synchronising both injector capacity and desired moulding features. For comprehensiveness, it was continuously sensitised over infinite scale as an explicit factor dependent on in-situ spatio-temporal injectant state perplexity with discrete slope and altitude for each polymeric character. In which congregant ranges of apparent viscosity and shear thinning index were conceived to characteristically assort most thermoplastics. Thereon results accorded aggressive conduit expansion widening for viscous incrust, while a very aggressive narrowing for shear thinning encrust; among them apparent viscosity had relative dominance. This important rationale would certainly form a priori design basis as well diagnose filling issues causing several defects. Like this the proposed generic design criteria, being simple would immensely benefit mould designers besides serve as an inexpensive preventive cliché to moulders. Its adaption ease to practice manifests a hope of injection moulding extremely alluring polymers. Therefore, we concluded that appreciating injectant׳s polymeric character to design exclusive sprue bush offers a definite a priori advantage

Differential-integral quadrature numerical solution for free and forced vibration of bidirectional functionally graded Terfenol-D curved beam

The dynamic behaviour of a bidirectional functionally graded Terfenol-D curved beam under a moving load is the focus of this study. Combined differential and integral quadrature solve the curved beam boundary value problem. A bidirectional functionally graded Terfenol-D curved beam’s damping, damped frequencies for different boundary conditions, and mode shapes were examined in free vibration investigations. Based on accessible literature data, the findings are reliable. Furthermore, DQ-IQ numerical technique findings examine the impact of many factors, including control gain, thickness, moving load velocity, bidirectional gradation index, and multi-moving load