Metal Endcaps Research Articles

Design, modeling and optimization of an adhesively bonded ring joint with U-section for ceramic cylindrical pressure hull of deep-sea underwater vehicles

The brittleness of ceramic increases the risk of damage or collapse when the ceramic cylindrical pressure hull is directly connected with a rigid part, especially under high hydrostatic pressure. To solve the above problem, this paper systematically explores the design, modeling and optimization of an adhesively bonded ring joint with U-section (ABRJ-U) to avoid the direct connection of the ceramic hull of a small hadal glider, Petrel, with the hemispherical metal end caps. The ABRJ-U is comprised of a U-shaped metal ring, a gasket, and epoxy adhesive layer. To optimize the design parameters, a mechanical model of ABRJ-U is established. The stress tests prove that the model has better efficiency in optimization, but lowered accuracy compared with regular finite element method. Considering the difficulty of obtaining a more accurate theoretical model, the optimization efficiency of regular finite element method is selected for further improvement by integrating the response surface methodology and multi-objective genetic algorithm. According to the optimization results, our optimization method considers the stress calibration of both the adhesive and gasket, simultaneously achieving a 20.8% reduction in the mass of ABRJ-U. The proposed methods also provide valuable reference for the design, modeling, and optimization of other bonded joints.

Design and optimization of a dual-port Helmholtz transducer for crosswell seismic survey

Given the limitations of conventional crosswell seismic sources, which struggle to reduce frequency by elongating the axial dimension of the transducer, this study introduces an innovative method for frequency reduction in such sources. The proposed approach entails adding metal end caps with orifices to the piezoelectric circular tube with both ends open. This modification transforms the originally cylindrical liquid cavity with both ends open into a dual-port Helmholtz liquid cavity. To begin with, the frequency reduction effect of the dual-port Helmholtz liquid cavity is theoretically demonstrated using the equivalent circuit method. Subsequently, the finite element method is employed to validate the accuracy of the equivalent circuit and to compare the radiation performance of the two transducer models. Further, the impact of the materials and structural parameters of end caps on the resonant frequency of the liquid cavity is investigated using the finite element method. Finally, four transducer prototypes are fabricated, and their conductance curves are tested in silicone oil to verify the feasibility of the proposed approach. The test results affirm that the dual-port Helmholtz transducer exhibits a lower resonant frequency of the liquid cavity, which aligns well with the simulation results. The proposed dual-port Helmholtz transducer offers a promising solution for achieving low-frequency emission in crosswell seismic sources. The research findings establish a solid theoretical foundation for the design and optimization of this transducer.

The Modeling Design and Analysis of Spherical-Cymbal Piezoelectric Transducer

The paper proposes a model and analysis of spherical-cymbal piezoelectric transducer. First, we select materials for force-sensitive element, the metal end cap and ring and epoxy resin. The load transfer law of the spherical-cymbal piezoelectric transducer is analyzed. Then, resonant frequency test, axial vibration displacement test and ultimate static pressure test are implemented in experiment. The experimental results show that the spherical-cymbal piezoelectric transducer outperforms the traditional cymbal piezoelectric transducer. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P _max</i> value can increase up to 10% under different geometric parameters. This paper is conducted to provide new insight into the design of cymbal piezoelectric transducer.

Shaped-Cumulative Charge as a Pyrotechnic Mean for a Pipe Bomb Deactivation

The aim of solved problem is a development of a new invasive means for improvised explosive devices deactivation. The idea is a quick and reliable disposal of improvised explosive device with construction system as a tube bombe. Such tube bomb has to be deactivated, dismantled and to do not explode. The development of shaped – cumulative charge was conceptually solved in a way to pushed down metal end caps of the tube bomb, to pick up explosive with a detonating fuse and to prevent from its explosion. Dismantled parts put to forensic test, for the improvised explosive device constructer revelation.

Optimisation of a Cymbal Transducer for Its Use in a High-power Ultrasonic Cutting Device for Bone Surgery

The class V cymbal is a flextensional transducer commonly used in low-power ultrasonic applications. The resonance frequency of the transducer can be tailored by the choice of end-cap and driver materials, and the dimensions of the end-caps. The cymbal transducer has one significant limitation which restricts the operational vibration amplitude of the device. This is the limit imposed by the mechanical strength of the bonding agent between the metal end-cap and the piezoceramic driver. Therefore, when there is an increase in the input power or displacement, the stresses in the bonding layer can lead to debonding, thereby rendering the cymbal transducer ineffective for high-power ultrasonic applications. In this paper, several experimental analyses have been performed, complemented by the use of Abaqus/CAE finite element analysis, in order to develop a high-power ultrasonic cutting device for bone surgery using a new configuration of cymbal transducer, which is optimised for operation at high displacement and high input power. This new transducer uses a combination of a piezoceramic disc with a metal ring as the driver, thereby improving the mechanical coupling with the metal end-cap.

Electrical Output Characteristics of Piezoelectric Ceramics Cymbal Transducer with Drop Weight Impact Techniques

In this study, the relationship between the generated voltages of piezoelectric ceramics Cymbal transducer to which impact mechanical energy was applied was studied. The generated voltages of the piezoelectric ceramics Cymbal transducer increased as the applied mechanical energy were increased. At a single impact mechanical energy, the generated voltages of the piezoelectric ceramics Cymbal transducer were much higher than the voltages of an uncapped piezoelectric ceramics disk. The generated voltages of the piezoelectric ceramics Cymbal transducer depended on the geometric parameters and the metal thickness of the end-cap. The generated voltage of piezoelectric ceramics Cymbal transducer with thick metal end-cap was lower than the voltage of transducers with thin metal end-cap.

Design, analysis and testing of a piezoelectric flex transducer for harvesting bio-kinetic energy

The increasing prevalence of low power consuming electronics brings greater potential to mobile energy harvesting devices as a possible power source. A new piezoelectric energy harvesting device, called the piezoelectric flex transducer (PFT), is presented and developed. A Finite Element Model (FEM) was developed to design and analyse the PFT. The PFT consists of a piezoelectric element sandwiched between substrate layers and metal endcaps that are able to amplify the axial force on the piezoelectric element. Based on the concept of the Cymbal transducer, the PFT can withstand higher forces, was retrofitted into a shoe and used to power a wireless sensor module whilst the subject with a body weight of 760N was wearing the shoe and ran at 3.1mph (1.4HZ on shoe), the PFT produced an average maximum power of 2.5mW (over 2MΩ load).

Modeling and experimental validation of unimorph piezoelectric cymbal design in energy harvesting

This article presents a unimorph lead zirconate titanate cymbal structure as an energy harvester. The unimorph lead zirconate titanate cymbal harvester was designed to be able to sustain higher mechanical loads by replacing the lead zirconate titanate monolayer with the lead zirconate titanate/steel composite between the metal end caps. Theoretical analysis was first carried out to predict energy-harvesting performance of the new cymbal design. A parametric study was also performed on two key geometric parameters to reveal trends that affect energy-generating performance for the cymbal structure. The dominant parameters that affect the performance are thickness of the metal end cap, the ratio of the radius of the apex to the radius of the cavity, and the thickness ratio of the lead zirconate titanate to the steel substrate. A specimen was then fabricated and tested on a load-frame to validate analytically predicted energy-scavenging performance. The specimen was tested under a 1-Hz cyclic load of up to 1940 N. The measured open-circuit output voltages for two different load inputs were close to the analytical results. The experimental results also indicate that the unimorph cymbal harvester can generate a power of 121.2 µW at 3.3 MΩ resistive load under 1-Hz cyclic load of 1940 N.

Pb(Ni1/3Sb2/3)O3-PbZrTiO3 Ceramic Sensors for Underwater Transducer Application

Cymbal is a class-V flextensional transducer that consists of thickness poled ceramic disc sandwiched between the two metal end caps which acts as a mechanical transformer. Cymbal transducers were fabricated using piezoceramic discs of compositions Pb0.988(Zr0.52Ti0.48) 0.976Nb0.024O3 (PZT type 5A) and Pb0.98La0.02 (NiSb)0.05[(Zr0.52 Ti0.48)0.995]0.95O3 (PNS-PZT). Piezoelectric and hydrostatic constants for PNS-PZT composition were on higher side. End capswere made up of brass sheet having thickness 0.5 mm. Underwater testing of the polyurethane moulded cymbal hydrophones were carried out in acoustic tank and compared. The resonance frequency for both the hydrophones was 10.1 kHz. PNS-PZT hydrophone shows higher sensitivity (-183.2 dB re 1V/μPa) compared to PZT type 5A (-191.2 dB re 1V/μPa) at resonance frequency. Directivity pattern observed for PNS-PZT is omni-directional near resonance frequency. Defence Science Journal, 2012, 62(4), pp.269-273 , DOI:http://dx.doi.org/10.14429/dsj.62.1718

Lung counting: comparison of detector performance with a four detector array that has either metal or carbon fibre end caps, and the effect on mda calculation

This study described the performance of an array of high-purity Germanium detectors, designed with two different end cap materials-steel and carbon fibre. The advantages and disadvantages of using this detector type in the estimation of the minimum detectable activity (MDA) for different energy peaks of isotope (152)Eu were illustrated. A Monte Carlo model was developed to study the detection efficiency for the detector array. A voxelised Lawrence Livermore torso phantom, equipped with lung, chest plates and overlay plates, was used to mimic a typical lung counting protocol with the array of detectors. The lung of the phantom simulated the volumetric source organ. A significantly low MDA was estimated for energy peaks at 40 keV and at a chest wall thickness of 6.64 cm.

Lung counting: Comparison of a four detector array that has either metal or carbon fiber end caps, and the effect on array performance characteristics

Abstract This study described the performance of an array of HPGe detectors, made by ORTEC. In the existing system, a metal end cap was used in the detector construction. In general, the natural metal contains some radioactive materials, create high background noises and signals during in vivo counting. ORTEC proposed a novel carbon fiber to be used in end cap, without any radio active content. This paper described the methodology of developing a model of the given HPGe array-detectors, comparing the detection efficiency and cross talk among the detectors using two end cap materials: either metal or carbon fiber and to provide a recommendation about the end cap material. The detector's counting efficiency were studied using point and plane sources. The cross talk among the array detectors were studied using a homogeneous attenuating medium made of tissue equivalent material. The cross talk was significant when single or multiple point sources (simulated to heterogeneous hot spots) were embedded inside the attenuating medium. With carbon fiber, the cross talk increased about 100% for photon energy at about 100 keV. For a uniform distribution of radioactive material, the cross talk increased about 5–10% when the end cap was made of carbon instead of steel. Metal end cap was recommended for the array of HPGe detectors.

Spectroscopic Evidence for Redox Isomerism in the 1,4-Diethynylbenzene-Bridged Heterobimetallic Cation [{Fe(dppe)Cp*}(μ-C≡CC6H4C≡C){Mo(dppe)(η-C7H7)}]PF6

Reaction of [FeCl(dppe)Cp*] with [Mo(C≡CC6H4-4-C≡CH)(dppe)(η-C7H7)], 1, and NaBPh4 in methanol gives the alkynylvinylidene complex [{Fe(dppe)Cp*}{μ-C≡CC6H4(H)C═C}{Mo(dppe)(η-C7H7)}]BPh4, [2A]BPh4, which is deprotonated to form the heterobimetallic, 1,4-diethynylbenzene-bridged complex [{Fe(dppe)Cp*}(μ-C≡CC6H4C≡C){Mo(dppe)(η-C7H7)}], 3. The alkynylvinylidene compound [2A]BPh4 exists as the major component of an equilibrium mixture with [Fe(dppe)Cp*}{μ-C═C(H)C6H4C≡C}{Mo(dppe)(η-C7H7)}]BPh4, [2B]BPh4, and is formed as a consequence of proton migration between the Cβ carbons of the vinylidene and alkynyl ends of the bridging ligand. Cyclic voltammetric investigations reveal that 3 undergoes two reversible one-electron oxidations to cationic [3]+ and [3]2+, which have been isolated as the [PF6]− salts after chemical oxidation. Computational (DFT) studies on [3]n+ indicate that while the HOMO of neutral 3 is rather heavily localized on the Mo center, in [3]+ the frontier orbitals are more evenly distributed over both metals, with the concentration of spin density being sensitive to the relative disposition of the metal end-cap fragments about the diethynylbenzene ligand. Experimental investigations on [3]PF6 by IR and EPR spectroscopy provide evidence for the coexistence of redox isomers [3A]+ and [3B]+, in which spin density is localized at the molybdenum or iron center, respectively. The solution IR spectrum of [3]PF6 exhibits an unusual four-band pattern in the ν(C≡C) region, consistent with the observation of two isomeric forms of [3]PF6, which are “valence trapped” on the short time scale of IR spectroscopy. In the frozen solution EPR spectrum, at 120 K, the spectroscopic signatures of both paramagnetic end-caps Mo(dppe)(η-C7H7) and Fe(dppe)Cp* are observed. The properties of [3]n+ are discussed with reference to the parent homobimetallics [{MLx}2(μ-C≡CC6H4C≡C)]n+ [MLx = Fe(dppe)Cp*, [4]n+, and Mo(dppe)(η-C7H7), [5]n+, n = 0, 1, 2].

Energy harvesting with a slotted-cymbal transducer

A cymbal transducer is made up of a piezoceramic disk sandwiched between two dome-shaped metal endcaps. High circumferential stresses caused by flexural motion of the metal endcaps can induce the loss of mechanical input energy. Finite element analysis shows that the radial slots fabricated in metal endcaps can release the circumferential stresses, and reduce the loss of mechanical input energy that could be converted into electrical energy. In this letter, the performance of a slotted-cymbal transducer in energy harvesting was tested. The results show that the output voltage and power of the cymbal are improved. A maximum output power of around 16 mW could be harvested from a cymbal with 18 cone radial slots across a 500 kΩ resistive load, which is approximately 0.6 times more than that of the original cymbal transducer.

Stress‐Biased Cymbals Using Shape Memory Alloys

Cymbals and other flextensional transducers demonstrate high effective displacements due to the amplifying nature of the metal endcaps, while stress‐biased RAINBOW actuators display high displacements due to enhanced 90° domain wall translational processes that result from the tensile stress in the surface region of the lead zirconate titanate (PZT) layer created during manufacturing. A new class of transducers, called stress‐biased cymbals (SBC), was developed that couples the operational principles of cymbal and stress‐biased actuators. Pre‐stressing the PZT in the cymbal was accomplished using a flat‐trained shape memory alloy endcap. Hysteresis loops were measured using a Sawyer–Tower circuit for different pre‐stress levels. Enhancements in the differential dielectric constant of more than 70% and the effective d33 of the cymbal by ∼57% were observed, suggesting greater 90° domain wall motion in the SBC compared with the standard cymbal device. The stresses developed during the fabrication process were measured and compared with theoretical models. Additional performance characteristics including dynamic dielectric constant, loss, and radial resonance frequency of the devices are also reported.

Statistic analysis of electromechanical response in cymbal piezocomposites

The cymbal design consists of a piezoelectric ceramic disk sandwiched between two truncated conical metal endcaps using epoxy as a bonding agent. The influence of the epoxy bond on actuator performance has been evaluated by manufacturing cymbals with two different adhesives and application methods, manual and semi-automatic. In the present work, a statistical rupture test has been developed for the study of the electromechanical behaviour of the cymbal piezocomposites. Using the generated charge versus applied force curves, both the effect of the bonding layer and the reliability of this device has been studied and the interpretation of the behaviour of the cymbal piezocomposite during the application of the compression force was established. A bonding layer with lower presence of defects will mean a larger break force. Weibull statistics has been used to describe the variations in the breaking behaviour of the cymbal piezocomposites, and it is employed to predict the maximum operation force.

Lifetime estimation and design of elastomeric seals with reinforced metal end caps

This feature demonstrates an attempt to improve the serviceability of elastomer seals by optimizing the shape of a seal with metal end caps, which limit extrusion and increase lifetime. An expression for calculating the lifetime of the elastomeric components based on the time to onset of fracture was investigated and used in conjunction with experimentally derived parameters to predict seal lifetime for a range of temperatures and pressures.

Ferroelectric transducer arrays for transdermal insulin delivery

The goal of this research was the development of a portable therapeutic device for the treatment of diabetes. A 3×3 cymbal array has been successfully tested in noninvasive insulin delivery experiments. The cymbal is a composite flextensional transducer constructed from a poled PZT ceramic and shaped metal endcaps that amplify the transducer motions by two orders of magnitude. Nine cymbals are wired in parallel and potted in polyurethane to form the flat panel arrays. When driven near resonance (20 kHz), the array generated a low intensity acoustic beam of 100 mW/cm2. Animal experiments on hyperglycemic rats and rabbits demonstrated the ultrasonic enhancement of transdermal insulin delivery.

The solid-state lighting revolution

For THE last 125 years we have been able to shine light whenever and wherever we need it by simply flipping a switch. This revolution started when Thomas Edison developed the first commercial electric light bulb in 1879, and very little has changed since. The reason for this is partly because new technologies have all followed the same old paradigm: fragile, gas-filled glass envelopes with metal end-caps that produce an orb of steady, white light. However, this may soon change with the dawn of the second lighting revolution: solid-state lighting.

풍차형 초음파 선형 모터의 양방향 운동

In this paper, a single phase driven piezoelectric motor design was presented for linear motion Two metal/ceramic composite actuators, a piezoelectric ring which was bonded to a metal endcap from one side, were used as the active elements of this motor. The motor was composed of a piezoelectric ceramic, a metal ring which has 4 arms, and a guider. Motors with 30 [mm] and 35 [mm] diameter were studied by finite element analysis and experiments. As results, the maximum speed of motor was obtained at resonance frequency. When the applied voltage of the motor increased, the speed was increased. Also, bidirectional motion of the motor was achieved by combining two motors which have different resonance frequency. But the characteristics of bidirectional motion were not equaled, because of the problem of reproduction on the fabrication and the experiment. If present motor is used at the auto-zoom device of a camera, it will have much advantage. Because the direct linear motion can be achieved with a simple structure of motor and no gearbox of total system.

Nonlinear Dynamics of Shallow Spherical Caps Subjected to Peripheral Loading

The behavior of spherical caps under radial dynamic edge loading in theform of step loading of infinite duration in the time domain has beeninvestigated. The aim here is to present a mathematical model of shallowshells of revolution which may undergo snap-through buckling as a resultof the radial displacement of the circular boundary. The snap-throughbuckling under such a loading condition is contrary to intuition and itseems not to have been previously observed. In this search it isobserved that snap-through buckling is also possible under peripheraldynamic loading conditions. The amount of snapping is remarkable whenthe cap has an opening around the apex. A technological application ofthe peripheral type of loading is seen in metal-ceramic compositetransducers achieved by installing a piezoelectric ceramic disk betweentwo metal end caps. The radial motion of the ceramic is converted into aflex-tensional motion in the spherical caps. As a result, a largedisplacement is obtained in the perpendicular direction, which mayresult in snap-through buckling. For the numerical solution of theproblem a computer program, using a linearized finite elementincremental-iterative approach based on updated Lagrangian formulationis developed, and the whole process is accomplished using the Newmarkmethod as the time integration scheme.