Metal Diaphragm Research Articles

Precision pneumatic pressure measurement with diaphragm-based mechatronic devices

A clamped circular metallic diaphragm, with shallow spherical shell deformation, elongates spherically proportional to the pressure acting on it. By making use of the inflation characteristics and mechanical properties of the diaphragm, three types of pneumatic pressure sensor are proposed in this article. In the first type, an optical mirror is engraved on its outer surface in an optimal position falling midway between its vertex and circumference. A laser beam is made to incident on the mirror and it gets deflected to fall over a matrix of photocells; the excitation of a particular cell in the coordinates of the matrix determines the pressure acting on the diaphragm. In the second proposal, a weightless secondary coil of a transformer is fixed around the vertex of the diaphragm which would move around a stationary magnetic core. The excitation of the primary coil wound over the magnetic core causes a voltage to be picked up in the secondary coil which would depend upon the displacement of the vertex because of pressure. The third type of the transducer is a capacitance pickup arrangement wherein the pressure is converted into capacitance and it is sensed and displayed as pressure. Furthermore, as an extension of the work, the motion of the diaphragm is mechanically coupled to a stylus for producing hard copy of the pressure over a strip chart.

Microspeaker Diaphragm Optimization for Widening the Operating Frequency Band and Increasing Sound Pressure Level

We report on the optimization of a microspeaker diaphragm for widening the working frequency band between its first and second eigenfrequencies and increasing its sound pressure level (SPL). A metallic diaphragm produces a larger magnetic force and thus a higher sound pressure level; therefore a Ni-coating on a common poly ethylene naphthalene (PEN) diaphragm is appropriate. For the best diaphragm design, it is important to simultaneously optimize the diaphragm shape and the Ni-coating distribution on the top of the diaphragm. Since complete Ni-coating increases SPL but also reduces the frequency band, special attention must be paid to the Ni-coating. We solved the optimization problem by a two-step approach: standard shape optimization of a PEN diaphragm for widening the frequency band, followed by distribution optimization of the Ni material on the diaphragm. To facilitate the Ni distribution optimization, we formulated the problem as a special topology design optimization. Since the optimization requires a coupled analysis involving the electromagnetic field, mechanical vibration and sound radiation, the multiphysical system behavior should be properly modeled. After presenting the fundamental multiphysical equations, we provide shape and topology optimization procedures to find an optimal microspeaker diaphragm. We verified the validity of an optimized diaphragm configuration optimized by our method from a physical viewpoint.

High Sensitivity Fiber Bragg Grating Pressure Sensor Using Thin Metal Diaphragm

A high sensitivity pressure sensor design without a polymer transducer is demonstrated in this paper. The sensor uses a thin metal diaphragm as a pressure transducer instead of a polymer. The sensor is tested to a maximum pressure of 100 psi and has a sensitivity of 0.0115 nm/psi, which matches the calculated sensitivity of 0.0127 nm/psi. The sensor is provides accurate measurement of the pressure and shows good repeatability in its readings. The sensor is also tested at the flow loop of the University of Tulsa, and shows a good match with the pressure readings of the flow loop.

Radar cross section of a complex-shaped cavity with a loaded metal diaphragm

We propose a method for calculating the monostatic radar cross section of a two-dimensional complex-shaped cavity, which contains a plane-layered medium in the form of a loaded metal diaphragm placed on a dielectric layer. The method is based on the combined boundary-integral/modal method and the variational Galerkin method with the use of dyadic Green’s functions. The results of calculating the angular dependences of the radar cross section for various parameters of the plane-layered medium are presented. Restrictions of the applicability and potential for further development of the method are indicated.

Electrodynamic analysis and synthesis of selective devices based on thin diaphragms in ridge waveguides

Problems of analysis and synthesis of microwave selective devices are solved in the case when such devices are the bandpass filters based on thin plane transverse metal diaphragms in ridge waveguides. The vector eigenfunctions and cutoff wave numbers of waveguides are calculated with the help of the partial-domain method taking into account the edge singularity of the electromagnetic field. The multimode scattering matrices of a cascade connection of reentrant resonators are calculated with allowance for the interaction of irregularities via higher modes of evanescent H and E waves in a waveguide. The amplitude-frequency and phase characteristics and the dimensions of synthesized bandpass filters are presented for the case of Π and H-waveguides.

Radar cross section of the cavity with a loaded metal diaphragm

We propose a method for calculating the monostatic radar cross section of a two-dimensional cavity containing a plane-layered medium in the form of a loaded metal diaphragm which is located between two dielectric layers. The method is based on the modal technique and dyadic Green’s functions. The numerical results for the angular dependences of the radar cross section are presented for various parameters of the plane-layered medium. Limitations of the method and the possibilities of its further development are pointed out.

Optimal design of resonant piezoelectric buzzer from a perspective of vibration-absorber theory

In this paper, an optimization technique is presented for the design of piezoelectric buzzers. This design technique aims at finding the optimal configuration of the coupled cavity and diaphragm structure to maximize the sound pressure output. Instead of measuring the material constants of the piezoelectric ceramic and the metal diaphragm, an "added-mass method" is developed to estimate the equivalent electromechanical parameters of the system on which an analogous circuit can be established. The electrical impedance and on-axis sound pressure level of the piezoelectric buzzer can be simulated by solving the loop equations of the electromechanoacoustical analogous circuit. An interesting finding of this research is that the nature of the piezoelectric buzzer bears remarkable resemblance to that in the dynamic vibration absorber theory. Much physical insight can be gained by exploiting this resemblance in search of the optimal configuration. According to the system characteristic equation, a design chart was devised to "lock" the critical frequency at which the system delivers the maximal output. On the basis of the analogous circuit and the vibration absorber theory, an optimal design was found with constrained optimization formalism. Experiments were conducted to justify the optimal design. The results showed that the performance was significantly improved using the optimal design over the original design. Design guidelines for the piezoelectric buzzers are summarized.

Recent progress of bulk metallic glasses for strain-sensing devices

By use of high strength, high elastic strain limit and low Young's modulus of bulk metallic glasses, strain-sensing devices were practically prepared and the performances of the trial products using the devices were investigated. As a result, a Coriolis mass flowmeter constructed from Ti–Cu-based bulk metallic glass pipe exhibits 28.5 times higher sensitivity than conventional flowmeters made from SUS316 pipe. A pressure sensor using a Zr-based bulk metallic glass diaphragm also exhibits 3.8 times higher sensitivity than the conventional sensor using SUS630 diaphragm. These results for the industrial products made of bulk metallic glasses are promising for future developments as industrial materials with high performance.

Development of a multi-material micropump

In this paper, the design of a multi-material micropump will be described. The micropump inhibits a very simple design and therefore is very cost efficient. The pump consists of one plastic part, one metal diaphragm, and three piezo lead-zirconate titanate (PZT) ceramics. The PZT ceramics, glued on a metal diaphragm, form two active valves (inlet and outlet valve) and one actuation diaphragm. The valve seats, the pump chamber, and the inlet/outlet interfacing channels are formed in the plastic body. Due to its function principle, the micropump is able to pump bidirectionally. The design of the micropump covers bubble tolerant and self-priming features. Therefore, design measures have been carried out to realize a large compression ratio and to reduce the capillary pressures of bubbles in the pump chamber. The pump is able to handle gases and liquids. The plastic body is made of poly-ether-ether-ketone, and the metal diaphragm is made of stainless steel. Therefore, a good chemical resistance will be given. First prototypes of the actuation unit have been manufactured and tested successfully. Each actuation unit is able to performa stroke ofmore than 40 μm. Furthermore, the plastic body has been realized by milling, and preliminary measurements were carried out. For future work, the development and optimization of an improved micropump using microinjection moulding instead of milling are envisaged.

New apparatus for calibrations in the range of 2 kPa absolute pressure

Capacitance diaphragm gauges (CDGs) are precise electromechanical pressure sensors in which the displacement of a stretched thin metal diaphragm is detected by the measurement of a capacitance. These are very accurate gauges, and are frequently used as transfer gauges. To calibrate such accurate low-pressure gauges, precise mercury manometers have been used. However, complexity, concern about mercury vapour, and cost of mercury manometers have made it difficult to use these manometers in many industrial calibration laboratories. As a substitute, gas-operated piston gauges can be used for the calibration of such low-pressure gauges. However, the minimum pressure that is necessary to balance the tare weight, which generally corresponds to a pressure of several kilopascals, is a major obstacle. To reduce this minimum operating pressure, we adopted a variable bell-jar pressure method. To realize this method effectively, we developed a new mass-handling device that makes it possible to add or remove weights up to 200 g easily, with a resolution of 10 g, without breaking the vacuum during the calibration. This calibration system can be used to measure pressures from 100 Pa to 2 kPa in the absolute mode. In this paper, we also present the calibration results for two types of CDGs with full-scale ranges of 1330 Pa and 1000 Pa, respectively.

Performance of a detonation driven shock tunnel

A detonation driven shock tunnel is useful as a ground test facility for hypersonic flow research. By attaching a convergent section ahead of the primary diaphragm in the driver section, the downstream operation mode became available to generate a high-enthalpy test flow. A 100 mm diameter shock tunnel was for the first time installed in the Laboratory of High-Temperature-Gas Dynamics (LHD), Institute of Mechanics, Chinese Academy of Sciences, and after its continuous refitments, a high performance detonation driven shock tunnel was achieved to generate high-enthalpy and high-Reynolds number test flows. A new method to burst a metal diaphragm with the downstream operation mode is discussed.

Magnetic-field-controlled optical transmission in a system of metal diaphragms with apertures and a thin dielectric interlayer

A system comprising two metal diaphragms with holes and a thin dielectric interlayer exhibits magnetic-field-controlled optical transmission. This phenomenon can be used, in particular, for the creation of light modulators.

Development of a High-Resolution Quartz Resonator Force and Weight Sensor With Increased Reliability

Test-analyze-and-redesign method is employed to develop a quartz crystal resonator (QCR) force and weight sensor with increased reliability for batch production. The sensor, which mainly consists of a QCR and a metal diaphragm structure, has the advantages of high resolution, digital output, and low cost. The failure mechanism of the single-diaphragm QCR sensor has been uncovered by experiments aiming at providing insight into the failure factors. In order to eliminate the failure stress and improve reliability, the sensor has been redesigned based on failure analysis results by designing a double-diaphragm structure. Life testing experiments for validating the effect of the corrective action show that reliability has been improved five times, and after redesign, the reliability satisfies the requirement of practical use. Accelerated life testing is performed to find acceleration factors and development stresses for batch production.

Demonstration for integrating capacitive pressure sensors with read-out circuitry on stainless steel substrate

Capacitive pressure sensors have lots of potential for commercial applications. However, successful commercial exploitation of highly miniaturized capacitive sensors is often inhibited by the presence of parasitic effects such as environmental noise and parasitic capacitances. Therefore, to alleviate the problems encountered in the capacitive pressure sensor approach, it is important to integrate the sensors and the circuitry as directly as possible. This paper builds on preliminary work reported previously by us [Sens. Actuators A 101 (2002) 231] and focuses on direct integration of read-out circuitry with microfabricated microsensors. These capacitive pressure sensors with three-candidate diaphragm materials (Kapton polyimide film, stainless steel, and titanium) are demonstrated the integration with read-out circuitry on stainless steel substrate. Several approaches for the demonstration of integration have been taken and their various degrees of successes are examined. As the final stage of this study, a commercially available MS3110 Universal Capacitive Read-out IC from Microsensors Inc. in its un-packaged, die-type was used. This chip in its die-form was integrated via wirebonding to the microfabricated sensors. The sensors that are tested using the IC have only the metal diaphragms of stainless steel. The measured value of relative voltage change is 2.85% over the applied pressure range from 0 to 75 kPa. This sensor contains a gap of 21 μm and has a sensitivity of 0.92 mV/kPa.

高温動作用ダイヤフラム一体型圧力センサの開発

A pressure sensor for use in a high temperature atmosphere (150˜250°C) has been developed. The pressure sensor consists of Cr-O thin film strain gauges, electrode films and an oxidation resistance film, which are all sputter deposited on a metal diaphragm covered with an SiO2 insulator. For the pressure measurement, a photolithographically patterned Wheatstone bridge circuit of the Cr-O thin film strain gauges was used. The output voltages showed good linearity with pressure and little hysteresis even at a temperature of 250°C. In order to prevent oxidation of the strain gauges at high temperatures, some sputtered oxidation resistance films were examined. It was shown that non-oxide films such as AlN and Si3N4 films have good characteristics to prevent oxidation of the strain gauges.

A simple microwave component for the vacuum window protection in an ECR ion source for ion beam processing

The main drawback of ECR ion sources for industrial applications is the high vulnerability of the vacuum dielectric window, when located in the line of sight of the plasma. We present the study of a simple microwave component consisting in a metallic diaphragm in the form of a thin rectangular resonant slit associated with a differentially pumped buffer waveguide dedicated to the window protection. This device substantially improves the performances of the source. A microwave power as high as 700 W could be efficiently transmitted through a slit height of only 1 mm cut in a 2 mm thick stainless steel plate.

39. Comparison of the predictive value of computed tomography with myelography versus MRI using exercise treadmill exam in lumbar spinal stenosis

imaging was used to identify at least one radiologically normal disc from the middle thoracic (T6-7 or T7-8) and lower thoracic (T9-10 or T10-11) regions in each volunteer for IDP measurement. Pressure measurements were taken with a needle-mounted thin film metal diaphragm pressure transducer (Gaeltec, Isle of Skye, Scotland). Local anesthetic was administered, and the needle was placed into the nucleus pulposa under fluoroscopic guidance. Nuclear pressure was measured while the subjects performed a sequence of maneuvers in the prone, sitting, and standing positions. In the prone, sitting upright, and standing upright positions, readings were taken with the needle oriented horizontally and vertically to assess the directional dependence of the sensor, while the rest of the positions were recorded with the needle orientated vertically. Global position and disc level comparisons were made using a two-way ANOVA, and pairwise comparisons were made using the Student-Newman-Keuls method. RESULTS: Intradiscal pressure measurements from one middle and one lower thoracic disc were taken in all but one of the participants; due to the inability to access a middle disc in one subject, two discs from the lower region were measured. Globally, different maneuvers had a statistically significant effect on IDP (p 0.0001). The highest pressures recorded were while the subject was sitting and holding 20 kg with arms flexed (mean SEM, 2.77 0.07 MPa), while the lowest pressures were observed while in the prone position (0.21 0.07). The thoracic level (middle or lower) from which the measurements were taken did not show an overall significant pressure difference (p 0.681). There was no significant difference between pressures takenwith needle oriented vertically versus horizontally (p 0.755). DISCUSSION: This study used a minimally invasive technique to measure IDP of the middle and lower thoracic discs in various body positions. Interestingly, there was not a significant difference in pressures recorded from the middle and lower levels of the thoracic spine despite apparently different mechanical environments. Comparison of pressures from the lumbar spine reportedbyNachemson in1970 to thoseof themiddle and lower thoracic spine show the magnitudes of the thoracic pressures to be similar to those reported in the lumbar spinebutwerenot consistentlyhigheror lower. CONCLUSIONS: The information presented here will aid in understanding intervertebral disc biomechanics, and its relationship to spine pathology and treatment. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts.

Barometric Pressure Oscillations in Houston Caused by the 1964 Alaska Earthquake

The ground motion due to Rayleigh waves of the 1964 Alaska earthquake was recorded by a microbarograph in Houston. This appears to be the only known instance when such waves have been thus recorded; consequently some information about it is hereby given to add to the ample documentation about this earthquake ( e.g. , Anonymous-1, 1968–1973; Wood, 1969). Brief mentions of this observation are made in Donn (1964), McGarr (1965, 1968), and an article in Time magazine (Anonymous-2, 1964). I regret the delay in the present publication. At the time of the earthquake (27 March 1964) the seismographic station at Rice University in Houston, Texas (29°43′N, 95°24′W) was equipped with a three-component modified Press-Ewing seismographic system (De Bremaecker et al. , 1963). A microbarograph had been added to record the thermonuclear tests then being conducted by the Soviet Union. The latter purpose was not accomplished, however, since these tests had ended by the time this last instrument started operating. The microbarograph consisted essentially of two chambers separated by a thin metal diaphragm. One of the chambers was open to the outside air; it was connected to the other chamber through a metal tube equipped with a vane, the opening of which could be adjusted. This arrangement reduced the instrumental response to periods greater …

701 携帯電話用メタルドームのクリック特性に及ぼす残留応力の影響

Research on the comfortable click characteristic is done about a Metal Diaphragm, using CAE effectively. The effect of residual stress for manufacturing process is influences of comfortable. The synthetic design by Virtual Manufacturing which went back to the forming process and put the influence of remains stress into the view is performed in that case. A result of this study, considered influence goes back to the forming process of a Metal Diaphragm, and affect the comfortable click characteristic as effective use of CAE.

On Reliability Evaluation of a Diaphragm in a Light Touch Switch

Fatigue characteristics of a metal diaphragm in a light touch switch are evaluated with experimental approach considering cyclic load acting on it. The approach consumes much time and costs for evaluation. In previous paper, we have described that the mechanical properties of stainless steel have anisotropy and the fatigue characteristics must be discussed considering the large scatter of material properties induced by the anisotropy. Therefore, the purpose of this study is to establish a simple method to evaluate the reliability of diaphragms with the consideration of anisotropy. The proposed approach consists of three procedures. Firstly, residual stress after press forming is evaluated by finite element method (FEM), and response curves when the pushing load is applied on the diaphragm are also analyzed. And, the stress amplitude and the mean stress at every point on the diaphragm can be calculated. Secondly, the experimental database about S-N curve and Goodman diagram considering the effect of anisotropy have been prepared. Finally, the fatigue lives considering failure probabilities on the diaphragm can be estimated by comparison of Goodman diagram with numerical results. Obtained results revealed that the proposed approach is very useful for the reliability evaluation of the diaphragm.