Actuators ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 87
Author(s):  
Nicholas A. Jones ◽  
Jason Clark

This paper presents a structural geometry for increasing piezoelectric deformation, which is suitable for both micro- and macro-scale applications. New and versatile microstructure geometries for actuators can improve device performance, and piezoelectric designs benefit from a high-frequency response, power density, and efficiency, making them a viable choice for a variety of applications. Previous works have presented piezoelectric structures capable of this amplification, but few are well-suited to planar manufacturing. In addition to this manufacturing difficulty, a large number of designs cannot be chained into longer elements, preventing them from operating at the macro-scale. By optimizing for both modern manufacturing techniques and composability, this structure excels as an option for a variety of macro- and micro-applications. This paper presents an analytical compact model of a novel dual-bimorph piezoelectric structure, and shows that this compact model is within 2% of a computer-distributed element model. Furthermore it compares the actuator’s theoretical performance to that of a modern actuator, showing that this actuator trades mechanical efficiency for compactness and weight savings.


Author(s):  
Richard Holdich ◽  
Serguei Kosvintsev ◽  
Iain Cumming ◽  
Sergey Zhdanov

In filtration, the concept of pore size is not easy to define. In microfiltration, there are numerous advantages in employing a surface filtering membrane, rather than one relying on depth filtration mechanisms from a tortuous pore flow channel. Modern manufacturing techniques provide means to produce surface filtering membranes. For filtration, it is shown that a suitable pore design is an array of long thin slots. An analysis of fluid flow through the slots suggests that a short slot is adequate, but experimental data with suspended material indicates that slot length is important. Using long slots and careful control of the flow through the membrane it is possible to filter deforming particles such as oil drops from water.


2021 ◽  
Vol 65 (2) ◽  
pp. 106-112
Author(s):  
Ekaterina Andriushchenko ◽  
Jan Kaska ◽  
Ants Kallaste ◽  
Anouar Belahcen ◽  
Toomas Vaimann ◽  
...  

So far, Permanent Magnet (PM) clutches have been broadly used as torque transmission devices. With the aim of effective utilization of materials and energy in the manufacturing of PM clutches, design optimization has been widely applied. Generally, PM clutches are optimized applying linear dimensions as optimization parameters. On the contrary, optimization of PM clutch shapes has not been done extensively. Therefore, this paper performs optimization of PM clutch shapes with the following objectives: maximum tangential attraction force and minimum volume of utilized materials. To form optimal shapes, the points on the clutch surface are chosen as optimization parameters. The optimization is carried out using Ārtap framework in connection with COMSOL software, where the 3D model of the clutch has been created. After the optimization, the tangential attraction force has increased by 13 % and the volume of the clutch has been reduced by 24 %. Although the obtained shapes appear to be highly intricate, it does not pose an obstacle for modern manufacturing techniques.


Author(s):  
The Tam Nguyen ◽  
Roland Bigret

Abstract • The rotating equipment monitoring, protection and diagnostic system is based mainly on the knowledge of bearing structure vibrations and shaft relative vibrations. The vibration measurements are performed respectively by seismic transducers and proximity probe transducers. • Measured signals are affected by uncertainties, the most significant sources of which could be mechanical and electrical runout. • These uncertainties are mentioned by well known standards which recommend or dictate general rules but do not give any advice or procedure in view of reaching the main objective, that is to optimize the efficiency of the monitoring, protection and diagnostic system to improve machine reliability. • This paper gives two examples showing the effect of inaccuracies, due to noise, on the interpretation of the machine vibrations. • One validation procedure identifying true noise will be given, using the rotor slow roll principle. • Noise suppression will be presented requiring sampling and resampling of time domain signals taken on a non synchronous mode. A newly designed software will be used. • Mechanical runout could induce inacurracies on rotors low speed balancing. • Noises could create harmful forces on the rotor in a magnetic bearing system. • Modern manufacturing techniques can minimize mechanical runout in order to avoid noise suppression which could generate additional incaccuracies.


Author(s):  
Nicole L. Key ◽  
Patrick B. Lawless ◽  
Sanford Fleeter

High Cycle Fatigue (HCF) is a fundamental weakness in the technology base for turbine engines. Modern compressor designs feature closely spaced blade rows of low aspect ratio increasing the strength and complexity of aerodynamic forcing functions. Also, modern manufacturing techniques produce blisks with low levels of mechanical damping. Thus, classic simplified views of the forcing functions may no longer be sufficient to accurately predict blade response. The concept of the “average wake” and the role that deviations from this average, or wake variability, plays as an HCF driver become important. Experiments are performed in the Purdue Transonic Research Compressor where two different but geometrically similar rotor blades from the same blisk are investigated; one that produces a near nominal wake and another that demonstrates significant variability according to thermal anemometry measurements. The Particle Image Velocimetry (PIV) measurements provide both phase-locked and instantaneous views of the wake structure showing variability in the individual wake structure.


2021 ◽  
pp. 1-46
Author(s):  
Jitendra Kumar Katiyar ◽  
Ranjeet Kumar Sahu

1981 ◽  
Vol 9 (2) ◽  
pp. 139-145
Author(s):  
I. G. Lang

Modern manufacturing techniques which have been developed in respect of interconnection and packaging systems using printed circuit boards, are outlined. It is shown that these systems are capable of meeting present and future requirements for component mounting, including VLSI.


Author(s):  
Chelsea Ritter ◽  
Beda Barkokebas ◽  
Youyi Zhang ◽  
Mohamed Al-Hussein

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