Fem Simulation

This paper refers to a silicon micromachined tuning fork gyroscope, which is driven via two piezoelectric thin film actuators. The device responds to an external angular rate by a torsional motion about its sensitive axis due to the Coriolis effect. The shear stress in the upper torsional stem, which is proportional to the angular rate, is detected via a piezoresistive readout structure. In addition to the wanted signal corresponding to the angular rate, there are unwanted contributions from the drive motion, e.g., from mechanical unbalances and from asymmetries of the piezoelectric excitation induced by fabrication tolerances. These effects, which disturb the sensor signal with varying contributions in amplitude and phase, have already been examined for capacitive surface micromachined sensors. In this paper, they are identified for a piezoelectrically driven, bulk-micromachined gyro and compared to results of FEM simulations. System-level simulations are performed and show possibilities to compensate the main parasitic effects. Results of eliminating the mechanical unbalance by femtosecond laser trimming are presented and compared with the simulations.

In this work we define a performance measure for capacitive micromachined ultrasonic transducers (cMUT) in the form of a gain-bandwidth product to investigate the conditions that optimize the gain and bandwidth with respect to device dimensions, electrode size and electrical termination resistance. For the transmit mode, we define the figure of merit as the pressurebandwidth product. Fully-metallized membranes achieve a higher pressure-bandwidth product compared to partially metallized ones. It is shown that the bandwidth is not affected by the electrode size in the transmit mode. In the receive mode, we define the figure of merit as the gain-bandwidth product. We show in this case that the figure of merit can be maximized by optimizing the electrode radius. We present normalized charts for designing an optimum cMUT cell at the desired frequency with a given bandwidth for transmit or receive modes. The effect of spurious capacitance and liquid loading effect are considered. Design examples are given to clarify the use of these charts.

Deep drawing process of sheet metal is mostly used for cup shape forming. For cup shape forming a limiting value of blank diameter, for which value we can successfully draw a cup. If the punch diameter, efficiency factor and all the process parameters are fixed, and we increase that value of blank diameter, then the limit value of failure can be obtained. The ratio of maximum blank diameter which is successfully drawn to the punch diameter is called LDR (Limiting Drawing Ratio). Analytically we can find out the value of LDR. We can find out the value of LDR also from Experiments. But there is a big difference between the analytical value and experimental value. The value of LDR is also find out by the software simulation of deep drawing process and this value is very close to the experimental value of LDR. So with the help of simulation we can predict the value of LDR, which can reduce the experimental set up cost. We are using RADIOSS software for FEM simulation of deep drawing process.

Landslides at continental margins are natural hazards for submarine installations and coastal regions. The occurrence of gas hydrates at continental margins is thought to be one major cause for these slides. It is assumed that the decomposition of gas hydrates increases the water content of the host sediment and thus lowers the strength of the soil. In order to predict

Laser Engineered Net-Shaping (LENS ® ) is an emerging manufacturing technique that ensures significant reduction of process time between initial design and final components. The fabrication of fully dense parts with appropriate properties using the LENS ® process requires an in-depth understanding of the entire thermal behavior of the process. In this paper, the thermal behavior during LENS ® was studied, both numerically and experimentally. Temperature distribution and gradient in the fabricated part were obtained by finite element method (FEM) simulation. The numerical results are in good agreement with the experimental observations. The numerical method may be used to optimize process parameters and predict the thermal response of LENS ® fabricated components.

The ring-rolling design for a large-scale ring product of Ti-6Al-4V alloy was investigated by a calculation method and FEM analysis. The ring-rolling design includes geometry design (rolled ring dimensions, blank and billet size, etc.) and optimization of process variables. The design criteria are to achieve minimal forming loads, uniform distributions of strain and temperature, and defect-free ring products. In order to predict the forming defects such as the flow localization or instability, shear bands and surface cracks, the processing-map approach considering flow instability was used with FEM simulation. The experimental analysis based on the flow instability map approach was carried out to predict the formation of rolling defects in plane-rolled Ti-6Al-4V rings. An optimum process design to obtain sound Ti-6Al-4V rings without forming defects was suggested and its validation was made by the comparison between the experimental data and FE analysis results.

Expansion and reduction are the two common end forming processes for tubes. In the tube end expansion process using a square punch, it is difficult to obtain a small corner radii due to the stretching of the tube around the punch corners. The wall thickness around the corners is small when compared to the side wall. Hence, a tube having a poor square look is formed. In this study, a 2-stage end expansion of a round tube end into a square section having an improved square look i.e. small corner radii and increase in wall thickness around corners is developed. In the 1st stage, the tube end is flared into a cone shape using a 30 conical die by axial compression. In the 2nd stage, the conical end of the tube is drawn through a taper square die using a conical bottom square punch, and a near square section is formed. A 15% ironing ratio is applied during the drawing process to flatten the side wall of the square. Experimental and FEM simulation were performed to evaluate and to verify the forming process. Although the height of the square section increases when the punch stroke at the 1st stage is increased. However, this increase is limited by the buckling of the pipe at the circular section of the thick blank tube. Since the conical end is drawn into a square section having different radial lengths, the bottom of the square section is uneven. The uneven bottom end is trimmed off in the later process. A square section having a maximum height of 32 mm after trimming is successfully obtained from the experiment for the punch stroke, S=44 mm using an API 5 L tube. (C) 2013 Elsevier B.V. All rights reserved.

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... Permissions & Reprints. A finite element analysis of orthogonal machining using different tool edge geometries. Yung-Chang Yen, Anurag Jain and Taylan Altan Corresponding Author Contact Information , E-mail The Corresponding Author. ...

Microstructure and material flow of aluminum alloys have a significant influence on the mechanical properties and surface quality. In extrusion of aluminum billets at high temperatures the microstructure is dependent on the alloy and the forming and temperature history. A prediction of grain size and precipitation is of increasing importance in order to design the process by adjustment of parameters such as punch speed, temperatures, and quenching. To give references for microstructure prediction based on material flow, and with it strain and strain rate history, this paper deals with the microstructure during the extrusion process of AA6060, AA6082, and AA7075 alloys. Billets have been partly extruded to axisymmetric round profiles and the microstructure of the press rests consisting of the billet rests in container and die has been considered. Furthermore, these rests have been analyzed to show the material flow, dynamic and static recrystallization based on macro etchings and visible microstructure under different conditions, e.g. as in the area of high strain rate near the container wall, or in dead zones [I]. To allow an accurate simulation of the extrusion process, punch force and temperature conditions during the tests have been measured and are presented in this paper, too.

MEMS (Microelectromechanical Systems) refers to the technology integrating electrical and mechanical components with feature size of 1~1000 microns. MEMS comb accelerometers have been successfully applied for air-bag deployment systems in automobiles. In this paper, the design optimization of a poly- silicon surface-micromachined MEMS comb accelerometer is discussed. The device uses folded-beam structure to enhance the sensitivity. The movable mass is

The fatigue and wear behaviour of PVD coatings on cemented carbide inserts with various cutting edge radii are investigated experimentally and analytically in milling. The inserts with cutting edge radii from 8 up to 35 µm were manufactured by honing and micro-blasting. The tool wear progress was depicted through Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) microspectral analysis. The Finite Elements Method (FEM) simulation of the contact between the tool and the workpiece highlights the effect of the cutting edge radius on the first coating fracture and the further wear development. The wear behaviour of the cutting edge radii manufactured by honing, in comparison to the corresponding ones by means of micro-blasting, is significantly enhanced, whereas the cutting edge radius increasing can lead to a higher tool life.

The film deposition conditions on individual specimens in the vacuum chamber during a physical vapour deposition coating procedure cannot be considered as constant. Depending among others on the magnetic field distribution in the vacuum chamber as well as on the specimen fixture geometry and kinematics, the coating hardness and mechanical properties may vary. In order to investigate the effect of coating hardness and strength on the cutting performance in milling, (Ti Al )N films having thickness 46 54 from 3 to 10 mm and varying hardness were deposited on cemented carbides inserts. The coating material properties and especially their stress-strain laws were determined from the nanoindentation measurement results using a finite elements method (FEM) based evaluation procedure. The initiation and progress of the coating and tool wear in milling were studied using scanning electron microscopy and energy dispersive X-ray spectroscopy. The investigations revealed that as the coating grows thicker, its superficial hardness and strength decreases. For the thick coatings, however, this does not affect the cutting performance as much as for the thin coatings. In the case of thin coatings, a corresponding decrease of the film hardness and strength, diminishes significantly the cutting performance. A FEM simulation of the cutting process, whereas the coating mechanical properties vs. the film thickness are considered, elucidates the aforementioned results. ᮊ

The mixing in non intermeshing counter rotating internal batch mixers using Cam, Banbury and Roller rotor were evaluated experimentally using thermo scientific Haake and numerical FEM simulation using the commercial CFD package Polyflow. The Carreau -Yasuda flow model was used with mesh superposition technique to generate velocity profiles and particle trajectories for HDPE. Differences in velocity profile with respect to rotor angles were examined. Distributive mixing was evaluated experimentally, as well as numerically by particle tracking analysis. Flow stretching was evaluated using the length of stretch and mixing efficiency. Since material points stayed on their streamlines near to rotor wall in the Cam and Banbury mixer, Roller mixer was found to be generally more effective and efficient, although there were still areas of poor mixing found in all.

The fatigue and wear behavior of PVD coatings on cemented carbide substrates in milling are investigated experimentally and Ž . analytically through Finite Elements Method FEM simulation of the cutting process. Cutting inserts with different cutting edge radii and at various feedrates were examined. The initiation and progress of the tool failure is depicted through Scanning Ž . Electron Microscopy SEM and Energy Dispersive X-ray microspectral investigations of the used cutting edges. The FEM simulation of the contact between the tool and the workpiece enables a quantitative description of the influence of mechanical stress components on the coating fatigue failure. Hereby critical coating fatigue stresses determined by means of the impact test were considered. The experimental and computational results exhibit quantitatively the effect of tool radius and feed rate on the coating fatigue failure as well as on the overall cutting performance for various substrates and film structures. In order to utilize the superior characteristics of coatings towards improving the cutting performance, it is highly recommended to optimize the cutting insert wedge radius, as well as the cutting conditions. Herewith a premature coating failure and a consequent rapid wear development can be prevented. ᮊ

In recent years, growing demand for greater mechanical properties of PM steel components with competitive fabrication cost has led to significant innovations in different fields of powder metallurgy. Recent research has been focused on reaching higher performance with lower cost. To this end, the possibility of combining the conventional sintering and post-sintering processes for a particular powder composition has been introduced. Sinter-hardening is a result of the research conducted along this line. Elimination of any secondary operation such as quench-hardening by incorporating it in the sintering process (i.e. sinter-hardening) is of great interest, as it will lead to lower processing costs and equal, if not higher mechanical performance. However, to ensure the desired mechanical properties of the final component and robustness of the performance, critical aspects of the sinter-hardening process should be rigorously studied.

A new generation of composite pressure vessels for large scale market applications has been studied in this work. The vessels consist on a thermoplastic liner wrapped with a filament winding glass fibre reinforced polymer matrix structure. A high density polyethylene (HDPE) was selected as liner and a thermosetting resin was used as matrices in the glass reinforced filament wound laminate. The Abaqus 6.5.1 FEM package were used to predict the mechanical behaviour of pressure vessels with capacity of approximately of 0,068 m 3 (68 l) for a 0.6 MPa (6 bar) pressure service condition according to the requirements of the prEN 13923 standard, namely, the minimum internal burst pressure. The Tsai-Wu and Von Mises criteria were used to predict composite laminate and thermoplastic liner failures, respectively, considering the elasto-plastic behaviour of the HDPE liner and the laminae properties deducted from micromechanical models for composite laminates. Finally, prototype pressure vessels were produced in the defined conditions to be submitted to pressure tests. The comparison between the FEM simulations and experimental results are discussed in the present paper.

Door hinges are a key product in the automotive industry. The function of automotive door hinge is not only to close, open, and keep the open angle of the door but also to reduce traumas for passengers in the car when it is hit by another car. However, concentrated stress and strain occur at the corner of this product during forming, which can cause a crack if the shape of this area of the blank is not carefully designed. Accordingly, this article proposes a method for improving the press formability of a door hinge by changing the shape of the concerned area of the blank based on finite element method (FEM) simulations using the explicit dynamic code ABAQUS, version 6.5. The resulting optimized solution for robust forming was a corner radius of 7 mm, protrusion length of 18 mm, and protrusion height of 5 mm.

The finite element method is presented to attain the numerical simulation of the residual stresses field in the material treated by laser shock processing. The distribution of residual stresses generated by a single laser shock with square and round laser spot is predicted and validated by experimental results. With the Finite Element Method (FEM) model, effects of different overlapping rates and impact sequences on the distribution of residual stresses are simulated. The results indicate that: (1) Overlapping laser shock can increase the compressive residual stresses. However, it is not effective on the growth of plastically affected depth;

Titanium silicide (TiSi X ) contacts sputter deposited onto p-type SiC-wafers carrying a 5mm thick nitrogen-doped n-type (N D −N A =5 . 10 18 cm − 3 ) epitaxial layer have been electrically characterized. While the as-deposited contacts have revealed rectifying behavior, the current-voltage characteristic has became ohmic after sample treatment by rapid thermal annealing (RTA) in argon at temperatures above or equal to 1000°C. To determine the specific contact resistance z C, the common linear transmission line model (TLM) has been used. However, the z c values measured with the TLM method may be subject to systematic errors because the TLM is based on a simplified model of the metal -semiconductor contact. To quantify these errors, three-dimensional finite element models of TLM-structures with various geometries have been studied with the FEM-software ANSYS ® . By comparing the simulation results with experimental data, z c for annealed TiSi X contacts has been found to be 58·10 − 6 V cm 2 . This agrees very well with the best results published in the literature Phys. Stat. Sol. B202 (1997) 581-603). Secondary neutral mass spectrometry has been used to examine the reaction between TiSi X and SiC during RTA showing that for high temperature annealing (1180°C) the ternary phase Ti 3 SiC 2 is formed at the interface between a TiSi 2 overlayer and the SiC substrate.

The application of the methods of Computer Aided Engineering in sheet metal forming is looking back for several decades. It covers a wide range of activities from the product design through the process planning and process control including sophisticated methods of modelling and simulation. Among the CAE activities, recently the development of Knowledge Based Systems has become an emerging field. Most of the available Knowledge Based Systems are based on simplified plasticity theory and empirical technological rules. Therefore, they are usually not able to give accurate solutions and reliable predictions for complicated forming processes. In the last two decades, significant progress has been also achieved in the numerical modelling of forming processes. In spite of the enormous development of hardware and software facilities, the exclusive use of numerical modelling still seems to be very time-and cost consuming. Therefore the integration of these two fields has great practical importance. In this paper, the challenges and opportunities of the integration of Knowledge Based Systems and Finite Element Modelling in the process planning of multi-step sheet forming processes will be given.

The effect of thermo-mechanical properties of underfill, such as coefficient of thermal expansion (CTE) and stiffness (Young's modulus), on reliability of Flip Chip on Board (FCOB) under thermal cycling stresses is investigated in this study. 3-D and Quasi three-dimensional viscoplastic stress analysis using finite element modeling (FEM) is combined with an energy partitioning (EP) model for creep-fatigue damage accumulation, to predict the fatigue durability for a given thermal cycle. Parametric FEM simulations are performed for five different CTEs and five different stiffnesses of the underfill. The creep work dissipation due to thermal cycling is estimated with quasi 3-D model, while 3-D model are used to estimate the hydrostatic stresses. To minimize the computational effort, the 3-D analysis is conducted only for the extreme values of the two parameters (CTE and stiffness) and the results are interpolated for intermediate values.

Modeling shot peening process is very complex as it involves the interaction of metallic surfaces with a large number of shots of very small diameter. Conventionally such problems are solved using the finite element software (such as ABAQUS) to predict the stresses and strains. However, the number of shots involved and the number of elements required in a real-life components for a 100% coverage that lasts a considerable duration of peening make such an approach impracticable. Ideally, a method that is suitable for obtaining residual compressive stresses (RCS) and the amount of plastic deformations with the least computational effort seems a dire need. In this paper, an attempt has been made to address this issue by using the discrete element method (DEM) in combination with the finite element method (FEM) to obtain reasonably accurate predictions of the residual stresses and plastic strains. In the proposed approach, the spatial information of force versus time from the DEM simulation is utilized in the FE Model to solve the shot peening problem as a transient problem. The results show that the RCS distribution obtained closely matches with that of the computationally intensive direct FEM simulation. It has also been established, in this paper, that this method works well even in the situations where the robust unit cell approaches are found to be difficult to handle.

The influence of the initial thickness deviation of the tube wall on the deformation behavior during free hydraulic bulging was studied. The experimental study was performed with tubes that had an initial thickness deviation of approximately 1-4%. FEM simulation and theoretical speculation were also carried out in order to examine the experimental results. It was clarified that the cross sectional shape of the bulged tube maintained its circular shape until just before tube bursting. This tendency appeared independently of the amount of the initial thickness deviation. On the other hand, increase in thickness deviation during tube bulging depended on the degree of the initial thickness deviation, n-value and r-value. When the initial thickness deviation was large and n-value and r-value were small, the increase in thickness deviation was large.

During the recent 10-15 years, Computer Aided Process Planning and Die Design evolved as one of the most important engineering tools in sheet metal forming, particularly in the automotive industry. This emerging role is strongly emphasized by the rapid development of Finite Element Modelling, as well. The purpose of this paper is to give a general overview about the recent achievements in this very important field of sheet metal forming and to introduce some special results in this development activity. Therefore, in this paper, an integrated process simulation and die design system developed at the University of Miskolc, Department of Mechanical Engineering will be analysed. The proposed integrated solutions have great practical importance to improve the global competitiveness of sheet metal forming in the very important segment of industry. The concept described in this paper may have specific value both for process planning and die design engineers.

Mechanical properties of micro/nanoscale structures are needed to design reliable micro/nanoelectromechanical systems (MEMS/NEMS). Micro/nanomechanical characterization of bulk materials of undoped single-crystal silicon and thin films of undoped polysilicon, SiO 2 , SiC, Ni-P, and Au have been carried out. Hardness, elastic modulus and scratch resistance of these materials were measured by nanoindentation and microscratching using a nanoindenter. Fracture toughness was measured by indentation using a Vickers indenter. Bending tests were performed on the nanoscale silicon beams, microscale Ni-P and Au beams using a depth-sensing nanoindenter. It is found that the SiC film exhibits higher hardness, elastic modulus and scratch resistance as compared to other materials. In the bending tests, the nanoscale Si beams failed in a brittle manner with a flat fracture surface. The notched Ni-P beam showed linear deformation behavior followed by abrupt failure. The Au beam showed elastic-plastic deformation behavior. FEM simulation can well predict the stress distribution in the beams studied. The nanoindentation, scratch and bending tests used in this study can be satisfactorily used to evaluate the mechanical properties of micro/nanoscale structures for use in MEMS/NEMS. r

A new theoretical thermomechanical explanation of the uneven transverse temperature distribution. along the width for thin and wide hot rolled strip was proposed. In particular. starting from the irregular pressure and friction distribution which led to an uneven heat generation. a 20 mathematical model of calculating the t:'ansverse temperature distribution was presented. A physical explanation for this problem was given and the model .....as used as an essential basis to build a corresponding FEM simulation model. in which heat loss and generation were considered. Deformation and friction heat were described in details. For a clearer and more logical analysis, the heat generation problem was split into two parts: one for the strip centre. and one for the sides. in correspondence with the temperature peak points at 100 mm from the strip edge. Finally. the result shows that how the new theoretical model can lead to the exact interpretation of the measured uneven temperature distribution,

MEMS (Microelectromechanical Systems) refers to the technology integrating electrical and mechanical components with feature size of 1~1000 microns. MEMS comb accelerometers have been successfully applied for air-bag deployment systems in automobiles. In this paper, the design optimization of a poly- silicon surface-micromachined MEMS comb accelerometer is discussed. The device uses folded-beam structure to enhance the sensitivity. The movable mass is

In this article, we present the development of a novel probe for atomic force and lateral force microscopy, based on detailed finiteelements method (FEM) simulation. The FEM simulation is performed by means of the ANSYS 5.3 code. The developed probe consists of a micromachined silicon cantilever beam with an integrated micro-tip and piezoresistive sensors for detecting the lateral and vertical forces acting on the tip. The sensitivity for vertical displacement detection of 1.26 V/nm (for 1 k piezoresistor) and for lateral displacement detection of 0.46 V/nm (for 0.7 k resistors), by 0.6 V applied supply voltage was obtained. The principle of the probe, theoretical analysis, and experimental investigation of the probe sensor are discussed. The probe is suitable for operating in contact and noncontact atomic force microscopy (AFM) mode. The probe was utilized for imaging the surface of a chromium/quartz structure.

Piezoelectric transducer design involves mathematical modelling and experimental verification, which are necessary to validate the piezoelectric transducers. To make a precise numerical model by using finite element method (FEM), it is necessary to know dielectric, piezoelectric and mechanical properties. Therefore, damping is a hard property to measure,since it is related to mechanical loss and it is dependent on the frequency. In addition, damping values for piezoelectric and non-piezoelectrics materials, such as, resins, steel, aluminum etc., which are usually applied to assemble these transducers are not appropriately given for FEM software. The objective of this work is to determine damping values of these materials so they can be used in a FEM software. Damping values are determined by combining experimental and numerical techniques. For piezoceramics the damping is determined through the quality factor (Qm) obtained by measuring the admittance curve which are influenced by damping. By using these damping values, harmonic FEM simulations of piezoceramics and piezoelectric transducers are performed and the simulated electrical admittance curve is compared with the measured one. Damping determination for non-piezoelectric materials are done by comparing experimental and simulated results.

This paper presents a model for the evaluation of the optimal design of Darrieus vertical axis wind turbine by CFD analysis and experimental tests, through analyzing six models of Darrieus wind turbines, number of blades and tip speed ratio. For this purpose, a full investigation campaign has been carried out through a systematic comparison of numerical simulations with wind tunnel experiments data. The airfoil profile used in the turbine blades was DU06W200 and constant geometry dimensions to turbines. The experiments were done for all Darrieus wind turbine models by using a subsonic wind tunnel under open type test section with airflow speed range (3-7.65) m/s and different tip speed ratio TSR. The results show that Darrieus WT straight type can be self-starting at the wind velocity 3 m/s, where other types cannot be starting at less than wind speed 5 m/s. The rotational speed (N) increases for all models with the wind velocity increase. The power coefficient (CP) increases when t...

As failure criterion for sheet metal forming, conventional forming limit diagrams (FLD) are often used. The FLD is a strain based criterion, which evaluates the principal deformations at failure. Different investigations show that the FLD is dependent on the forming history and strain path. However, this is not the case for forming limit stress diagrams (FLSD). For this failure criterion, the principal stresses at failure are determined by FEM simulation of the Nakazima-test. Both, the FLD and the FLSD experimental investigations provide the basis for the sheet metal failure criterion. In contrast, continuum damage mechanics describe the damage evolution in the microstructure with physical equations, so that crack initiation due to mechanical loading can be predicted. By using the Gurson–Tvergaard–Needleman (GTN) damage mechanical model, a failure criterion based on void evolution was examined in this work. The parameter identification for the damage model will be discussed. The investigations demonstrate that FLD is inapplicable for complex forming processes with strain path changes. The FLSD is better suitable than the FLD for multi step forming processes. Micro-mechanical damage modelling with the GTN model also shows acceptable formability predictions, in spite of its generally insufficient consideration of the effective deviatoric stress fractions. The quality of failure prediction using continuum damage mechanics models is able to be increased by applying a more suitable damage models and a modern overall-scale modelling approach.

This paper presents the experimental determination of iron losses in an outer-rotor permanent magnet synchronous machine ({PMSM)} by using an inverse thermal model ({ITM)} in connection with transient thermal measurements. First, the theory and assumptions lying behind the method are presented. Afterwards, {3D} finite element method ({FEM)} based simulations are used to determine the flux density distribution and iron losses in the magnetic steel parts of the investigated machine. Thermal measurements are conducted to determine local iron losses in the stator tooth tips using the {ITM.} Finally, measurement and {FEM} simulation results are compared.

The stable conformation of a liquid-water drop on a horizontal cylindrical wire is studied. The stable conformation is established with various wire diameters. For each conformation of the drop the surface free energy is calculated using FEM simulation. The free energy for different drop shapes are compared with consideration to different volumes and contact angles. The effect of gravity on droplet shape with respect to wire diameter and droplet volume is observed. The droplet configurations under the influence of gravity and in the absence of gravity are observed and the shapes are described through coordinates of liquid-air and liquid-solid interfaces. The compensation of one interfacial energy with that of another is found. The wetting behaviour of liquid-drop on a wire is found to be significantly different from that on a plane surface under the influence of wire geometry. The numerical model was established taking liquid density at 1000kg/m3 and gravitational acceleration at 9.8 m/s 2. The numerical study is important in understanding the spreading of liquid droplets over cylindrical surfaces .The spreading of liquid over surfaces has got wide application in food industry, micro fluidics and more and in understanding the coating behaviour, liquid-solid and liquid-vapour interactions, material properties, etc.

In this paper a new flux-switching permanent magnet (FSPM) machine with 12 stator poles and 14 rotor poles is investigated, and compared to a machine with the same stator but 10 rotor poles. Two prototypes are studied by both finite element method (FEM) analysis and experimental measurements. The results show that the 12/14 pole prototype can provide about 7-12% higher torque, the torque ripple reduces from 8.5% to 5.1% and its synchronous inductance is also 15% higher. After optimization, the FEM simulation results show the 12/14 pole machine could provide 19% higher torque than the 12/10 pole machine and the torque ripple is further reduced to 2.3%.

Microstructure and material flow of aluminum alloys have a significant influence on the mechanical properties and surface quality. In extrusion of aluminum billets at high temperatures the microstructure is dependent on the alloy and the forming and temperature history. A prediction of grain size and precipitation is of increasing importance in order to design the process by adjustment of parameters such as punch speed, temperatures, and quenching. To give references for microstructure prediction based on material flow, and with it strain and strain rate history, this paper deals with the microstructure during the extrusion process of AA6060, AA6082, and AA7075 alloys. Billets have been partly extruded to axisymmetric round profiles and the microstructure of the press rests consisting of the billet rests in container and die has been considered. Furthermore, these rests have been analyzed to show the material flow, dynamic and static recrystallization based on macro etchings and visible microstructure under different conditions, e.g. as in the area of high strain rate near the container wall, or in dead zones [I]. To allow an accurate simulation of the extrusion process, punch force and temperature conditions during the tests have been measured and are presented in this paper, too.

A two-axes inclinometer-sensor has been realized by silicon bulk micromachining using etch compensation for convex comers and electrochemical etch stop for tight thickness control of the flexible silicon beams. The design procedure was assisted by a 3D finite-element method (FEM) simulation of the mechanical and electrical (piezoresistive effect) behaviour of the sensor, thus resulting in an optimized layout. The sensitivity can be easily adapted between 0.1 and I mV per angle of inclination (°) depending on the desired shock resistivity, which is about 100g even for the most sensitive layout. To protect the sensor chip a low-temperature bonding process has been developed, The sensors work properly in the range of + 80 ° inclination.

Un ni iv ve er rs si it tá á d di i B Br re es sc ci ia a, , I It ta aly Abstract: In this paper we propose a practical approach to develop a SAW parameter extraction technique and simulation method, contrary to the frequently used FEM/BEM numerical simulation technique. The new approach allows for accurate SAW device modelling through a versatile finite element method to automatically include the second order effects in the device by considering the complete set of partial differential equations. The eigenmodes and the harmonic admittance of a periodic structure obtained from the FEM simulations are used to extract the COM/P-matrix parameters based on a fitting technique that is already published in the literature. Comparison between the extracted parameters, using this technique, with currently published parameters for the same device specification was carried out and showed good agreement. As an example, a two dimensional delay line with 10 finger pairs per IDT was modelled using this approach, to outline the mechanical and electrical response of the device for variable acoustic modes and substrate thicknesses.

The low density, excellent high temperature mechanical properties and good corrosion resistance of titanium and its alloys have led to a diversified range of successful applications. As a consequence, there is a demand of increasing the capabilities of processing such alloys. The laser cladding technique allows direct metal deposition with an excellent metallurgical bond and a pore free fine grained microstructure. A nonlinear transient thermo-metallurgical model was developed to study the technique with titanium alloys to get a better understanding of the thermal and metallurgical underlying aspects. The calculated temperatures and phase transformations are compared with experimental tests.