Diaphragm Design Research Articles

Study on the Diaphragm Effect of the Beam Type Bridge

Our country bridge design code prescribe beam bridge often set the diaphragm to strengthen transverse connection. However, many countries think the beam bridge can reduce or do not set diaphragm. This paper respectively analyzed the deflection and stress of straight T beam bridge and curved box girder bridge with or without diaphragm, further demonstrated the diaphragm settings are necessary in straight beam bridge and curved beam bridge, especially when the vehicle and bridge width gradually increase, the diaphragm right force analysis and design becomes more and more important, it become an important part of the whole bridge design.

A biologically inspired silicon differential microphone with active Q control and optical sensing

A MEMS differential microphone is described in which the diaphragm design is inspired by the mechanics of directional hearing in the fly Ormia ochracea. The 1 mm by 3 mm diaphragm is designed to rotate about a central pivot in response to sound pressure gradients. The diaphragm is designed to have its dominant resonance mode within the audible frequency range and to have as little viscous damping as possible (to minimize the effects of thermal noise). The motion of the diaphragm is detected using an optical sensing scheme that includes a semiconductor laser (VCSEL), photodetectors, a mirror, and a diffraction grating. To minimize the adverse effects of the light damping on the response, an active feedback system is implemented to achieve active Q control. This uses the output of the optical detection scheme to drive the diaphragm through a capacitive actuator. The microphone and optoelectronics are packaged into an assembly that can be incorporated into a mock behind-the-ear hearing aid. The microphone is shown to achieve a noise floor that is approximately 17 dBA lower than what can be achieved using a pair of existing low noise hearing aid microphones to create a directional hearing aid.

Microfabricated Systems to Measure Marine Variables

The goal of this paper is to provide a basis for MEMS marine-specific sensors and their associated harsh environmental packaging. Specifically, this paper will discuss our efforts in the development of two microfabricated systems to measure marine variables - (a) MEMS-based electrochemical systems to measure marine nutrients and (b) reinforced MEMS pressure sensor to measure spatial depths. The electrochemical detection-on-chip module was fabricated using assembled polypyrrole (PPy) nanowires as the sensing element. The measurement of nitrate ions in a flow through environment is presented here. For the depth measurements, we developed the double diaphragm or reinforced configuration to measure pressure/depth at both higher sensitivity (27% higher) and wider linear operating range (> 400 psi, from combination of inner and outer diaphragms) compared to the conventional single diaphragm design.

An evaluation method for precast concrete diaphragm connectors based on structural testing

In the U.S., precast concrete floor diaphragms are a popular form of construction for parking, residential and commercial facilities. Discrete embedded connections bring together large precast concrete panels and transfer vertical and in-plane forces between panels. A consistent experimental procedure is necessary to meet the requirements of performance-based diaphragm design methodologies. In this paper, the authors propose a seismic design methodology for assessing stiffness, strength, and deformation capacity of precast concrete diaphragm embedded connections. They further offer details on developing a test module, loading setup, load histories, instrumentation, data reduction, reporting, and performance categorization.

Design and Simulation of Pressure Sensor for Ocean Depth Measurements

MEMS (Micro Electro Mechanical System) are usually defined as highly miniaturized devices combining both electrical and mechanical components that are fabricated using integrated circuit batch processing techniques. Pressure sensors are usually manufactured using square or circular diaphragms of constant thickness in the order of few microns. In this work, a comparison between circular diaphragm and square diaphragm indicates that square diaphragm has better perspectives. A new method for designing diaphragm of the Piezoresistive pressure sensor for linearity over a wide pressure range (approximately double) is designed, simulated and compared with existing single diaphragm design with respect to diaphragm deflection and sensor output voltage.

Eloctrostatic Pull-in Characteristic of Silicon Diaphragm for MEMS Micropump Design

Abstract Electrostatic actuation method is commonly employed for MEMS micropump mechanism which consists of diaphragm microstructure and parallel electrode. This work discussed on design and simulation of square silicon diaphragms and it characteristics for micropump application which supply voltage range of 0V-20 V. The characterizations of these diaphragms were based on the measurement on parameters such as diaphragm displacement as function of voltage applied and stress distribution. The simulations were carried out using CoventorWare2007. Results show that simulation deviate theoretical value in a range of below 15%. The displacement of the diaphragm was proportional to the physical geometry of the diaphragm. Pull-in voltage defines the limitation value for micropump operation.

Design and Optimization of Elastic Diaphragm in Miniature High-Temperature Pressure Sensor

The differential stress distribution of rectangular diaphragm with different sizes is simulated and analyzed using ANSYS. The results show that the maximal differential stress region on the rectangular diaphragm is located at the diaphragm center and the long side center, and also it gradually increases as the length-width ratio decrease. When the ratio is less than 1:2.2, the increase degree is not obvious and even falls slightly. According to this, the length-width ratio of the rectangular strain diaphragm was optimized as 1:2.2. Furthermore, the influence of stain diaphragm with different thicknesses and temperatures in differential stress distribution is discussed. It proves that the differential stress of the diaphragm is less affected by temperature, when the diaphragm thickness is properly chosen. The present results will provide the prerequisite for the design of miniature high-temperature pressure sensor in the future.

Integrated Analytical and Experimental Research to Develop a New Seismic Design Methodology for Precast Concrete Diaphragms

AbstractA new seismic diaphragm design methodology has been developed for precast concrete floor diaphragms. The knowledge required to create the design methodology was obtained through an integrated analytical and experimental research project using two Network for Earthquake Engineering Simulation (NEES) equipment sites. The activities of the project involved a sequence of integrated research tasks that systematically developed knowledge about diaphragm behavior from the reinforcement detail level to the structural system level. These tasks included the use of state-of-the-art experimental techniques made possible through the NEES facilities including hybrid simulation and large-scale shake table tests. Such techniques were crucial to the research as the complex behavior of precast diaphragms is not well described by simple analytical models or idealized experiments. Valuable industry oversight in the planning, execution, and technology transfer stages of the project guided the research activities, incl...

Design of an IPMC diaphragm for micropump application

Micropumps have gained a great potential to be applied as biomedical devices and micro systems. Because of low driven voltage, flexible operation, and self sensing ability, the ionic polymer metal composite (IPMC) material has been used as diaphragm of micropumps. This paper presents a novel design of IPMC diaphragm which helps to produce larger deformation and increase the durability of IPMC actuator. Unlike the conventional design of using a single piece of IPMC material clamped at all edges, we use several IPMC actuators (clamped at single edge) to drive elastic thin films. By eliminating the edge constrains for IPMC actuators, the new diaphragm can provide significantly larger deformation. Moreover, new design separates the IPMC from the pumping fluid and thus allows solvent to cover the IPMC and maintain long operating duration.An incorporation of physical induced stress model of IPMC actuators and the visual ANSYS environment is proposed to analyze the characteristic of the proposed diaphragms in comparison with the conventional one. Experiments have also been carried out to demonstrate the effectiveness of proposed model. Experimental results show that the new diaphragm design can produce deformation up to 0.4mm and maintain stable operation over 35min corresponding to a 3V–0.05Hz input signal, while the conventional design can produce only 0.2mm in deformation and the pumping performance decreases rapidly after 8min.

Strengthening of steel structures using the stiffening effect of cladding

Increasing the stiffness of some frames of a structure and making the frames work together by using diaphragms is an alternative way of strengthening steel frameworks. The diaphragm effect of the cladding is well known, but due to the very sophisticated interaction among frames and the cladding, the theoretical solutions need experimental verification.The Laboratory of Structural Engineering, Technical University of Budapest carried out experimental investigations on full-scale simple elastic-plastic frames in 1976. As a part of it, the effect of cladding was studied. The goal of this paper is to compare the experimental results to the results calculated according to the stressed skin diaphragm design method. As the examined structural layouts were different, virtual structures were used to make the results comparable.

Seismic testing and retrofit of steel deck roof diaphragms for building structures

An experimental program of nine steel deck roof diaphragm specimens was carried out to assess their seismic characteristics. The dynamically loaded diaphragms were able to develop the shear strength but not the shear stiffness values calculated using current diaphragm design methods. Furthermore, the shear stiffness decreased with increasing excitation amplitude. Diaphragm ductility decreased with the use of thicker deck panels and when the deck was oriented parallel to the loading direction. Most of the damaged diaphragms could be repaired to recuperate their original strength. A seismic retrofit scheme was effective in increasing the shear strength and stiffness of an arc-spot weld/ button-punch diaphragm.

Physical Analysis of a Biomimetic Microphone With a Central-Supported (C-S) Circular Diaphragm for Sound Source Localization

This paper presents a physical analysis of the biomimetic microphone designed with a central-supported (C-S) diaphragm for the sound source localization. A clover-stem-like C-S design is proposed and achieving 47% improvement of net diaphragm displacement in comparison with the conventional C-S diaphragm design. The new design can effectively not only compensate undesired deformation of sensing diaphragm due to gravity and residual stresses but also make the diaphragm more flexible for better sound pressure sensitivity.

Effect of nonlinear stiffness on the total harmonic distortion and sound pressure level of a circular miniature loudspeaker-experiments and simulations

This paper reports our study on the nonlinear stiffness of a few diaphragm designs used for miniature loudspeakers. For this study, the sample diaphragms were experimented for their stiffness curves using the laser vibrometry. Additionally, the stiffness curves were also obtained using finite element analysis (FEA). For calculating total harmonic distortion (THD), the electroacoustic system is modeled using the equivalentcircuit analogy. As a result of solving the coupled system of ordinary differential equations by the Runge-Kutta method, THD of three sample designs, characterized by different track patterns, were calculated and plotted as a function of frequency. The specimens were tested in a standard anechoic chamber for recording THD. Additionally, the sound pressure level (SPL) curves of these specimens were also recorded for comparison. It turns out that, despite no significant SPL difference, diaphragms with different track patterns shall, as a result, lead to substantial variations of THD. The consistence of our simulations with the measured THD has promised the feasibility of simulating THD by FEA for optimizing the design of track patterns for diaphragm.

Seismic design of low-rise steel buildings with flexible steel roof deck diaphragms - a Canadian perspective

Single-storey steel buildings in Canada are generally designed with a steel roof deck diaphragm to resist and transfer lateral loads to the vertical bracing system. Current Canadian seismic design provisions for these buildings are reviewed here with a focus on the design of the roof diaphragms. An equivalent static analysis method is generally used for these structures and comprehensive capacity design principles are applied to achieve a proper strength hierarchy in order to develop the intended yielding mechanism along the lateral load path. The method is illustrated with the help of a numerical example. The influence of roof diaphragm in-plane flexibility on the dynamic seismic response is discussed.

Computer aided modelling and diaphragm design approach for high sensitivity silicon-on-insulator pressure sensors

Silicon on insulator (SOI) pressure sensor diaphragm is a composite structure of the buried oxide and the SOI layer. This paper brings out the inadequacy of the existing analytical model in describing the deflection response of SOI square diaphragms and focuses on the computer aided burst pressure incorporated high sensitivity design approach using IntelliSuite for SOI pressure sensors. The simulation results indicate that the maximum sensitivity is achieved at a side length of 800 μm for burst pressures of 10 and 5 MPa and at 900 μm for burst pressure of 2 MPa. The new modified analytical model developed and presented in this paper for describing the load–deflection performance of SOI composite diaphragm is able to predict the deflection accurately when compared with deflection obtained by IntelliSuite FEA thus illustrating the validity of the computer aided design approach. Further the new model has demonstrated that the existing analytical model overestimates the deflection and hence inadequate for application to SOI pressure sensors. The subsequent piezoresistive analysis carried out on these SOI sensors also confirms these findings and the maximum sensitivity that can be achieved is estimated to be 56 mV/MPa/V for the burst pressure of 5 MPa. The experimental results reported in the literature have been compared with the simulation results to validate the design approach presented in this paper.

Analysis of Feature and Welding Consideration for Metal Bellows

The design and process of diaphragms for a welded bellow was studied in this paper, which is a flexible component in a piping system or vacuum equipment. Due to a lot of interactive effects on each procedure in the manufacturing for a welded bellow, furthermore the commercial FEM software ANSYS was used to construct a 3-dimension model for the displacement and modal analysis of bellows in which extensions and natural frequencies as well as mode shapes could be observed. The mechanical feature should be considered at the practical applications, i.e., to avoid the occurrence of resonant phenomena corresponding to pump operations and fluid delivery in a piping system. For the purpose of modeling validation, the axial tensile testing machine implemented the extension experiment for welded bellows. According to the results of simulation and experiment, the difference among them could be easily detected for the feature investigation for a design-oriented systemic analysis on the development of welded bellows.

SUS630 다이아프램을 이용한 반도체식 로드셀

The load cell is a force sensor and a transducer that is used to convert a physical force into a electrical signal for weighing equipment. Most conventional load cells are widely used a metal foil strain gauge for sensing element when force being applied spring element in order to converts the deformation to electrical signals. The sensitivity of a load cell is limited by its low gauge factor, hysteresis and creep. But silicon-based sensors perform with higher reliability. This paper presents the basic design and development of the silicon type load cell with an SUS630 diaphragm. The load cell consists of two parts the silicon strain gauge and the SUS630 structure with diaphragm. Structure analysis of load cell was researched by theory to optimize the load cell diaphragm design and to determine the position of peizoresistors on a silicon strain gauge. The piezo-resistors are integrated in the four points of silicon strain gauge processed by ion implantation. The thickness of the silicon strain gauge was polished by CMP under 100 <TEX>${\mu}M$</TEX>. The 10 mm diameter SUS630 diaphragm was designed for loads up to 10 kg with 300 <TEX>${\mu}M$</TEX> of diaphragm thickness. The load cell was successfully tested, the variation of <TEX>${\Delta}$</TEX>R(%) of four points on the silicon strain gauge is good linearity properties and sensitivity.

Diafragmas horizontais de piso em madeira, confeccionados com chapas de OSB e vigas I, submetido ao carregamento em seu plano

This work is focused on lightweight wood-frame constructions, which are accepted worldwide and may be considered feasible for use in Brazil as well. It presents the results of experimental tests on floor diaphragms subjected to lateral loads. This is the first time this kind of test is performed in Brazil. Thus, it brings up valuable information about this subject, giving technical information that may contribute to the design and construction of floor diaphragms employing local materials that come from planted forests. The main goal of this research is to evaluate the resistance and rigidity of wood light-frame floor diaphragms, when subjected to monotonic lateral forces acting in the plane of the floor. Full-scale floor diaphragm specimens (2.50 x 5.00 m) were tested with different constructive arrangements, and the influence of the following variables were examined: blocked vs. unblocked diaphragms, rigidity of the nailed joints between I-joists and sheathing; and distance between nails around the perimeter of the OSB boards. The tests showed that the blocked floor diaphragms enable nailing the whole perimeter of the boards, thus increasing its resistance and rigidity.

Design of a novel disposable piezoelectric co-polymer diaphragm based biosensor unit

Piezoelectric biosensors represent an economic alternative suitable for the detection of a variety of biomolecules. However, the difficulty of forming diverse structures and shapes using conventional piezoelectric ceramic and quartz crystals has so far limited their potential applications. Piezoelectric polymers and their co-polymers are considered as the favourable choice in the fabrication of different types of sensors due to their low cost, light weight and ease in forming delicate shapes. This paper demonstrates a disposable and simple piezoelectric diaphragm sensing platform consisting of a flexible co-polymer thin film and plastic sample holder. To test this platform, protein A was immobilized to form a bridge between goat immunoglobulin G (IgG) probe molecules and the gold electrode on the surface of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] film. The designed polyetheretherketone sample holders were applied to fix the piezoelectric co-polymer films. The apparatus was successfully used as an immunosensor and had the added advantage that the co-polymer thin film could be replaced. Optimum concentration of goat IgG probe molecules for fabricating the immunosensors was determined to be 3mg/mL. The P(VDF-TrFE)-based immunosensor of this type shows a good reproducibility and a broad dynamic detection range.

Development, fabrication, and characterization of hydrogel based piezoresistive pressure sensors with perforated diaphragms

Hydrogels have been demonstrated to swell in response to a number of external stimuli including pH, CO 2, glucose, and ionic strength making them useful for detection of metabolic analytes. To measure hydrogel swelling pressure, we have fabricated and tested novel perforated diaphragm piezoresistive pressure sensor arrays that couple the pressure sensing diaphragm with a perforated semi-permeable membrane. The 2 × 2 arrays measure approximately 3 × 5 mm 2 and consist of four square sensing diaphragms with widths of 1.0, 1.25, and 1.5 mm used to measure full scale pressures of 50, 25, and 5 kPa, respectively. An optimized geometry of micro pores was etched in silicon diaphragm to allow analyte diffusion into the sensor cavity where the hydrogel material is located. The 14-step front side wafer process was carried out by a commercial foundry service (MSF, Frankfurt (Oder), Germany) and diaphragm pores were created using combination of potassium hydroxide (KOH) etching and deep reactive ion etching (DRIE). Sensor characterization was performed (without the use of hydrogels) using a custom bulge testing apparatus that simultaneously measured deflection, pressure, and electrical output. Test results are used to quantify the sensor sensitivity and demonstrate proof-of-concept. Simulations showed that the sensitivity was slightly improved for the perforated diaphragm designs while empirical electrical characterization showed that the perforated diaphragm sensors were slightly less sensitive than solid diaphragm sensors. This discrepancy is believed to be due to the influence of compressive stress found within passivation layers and poor etching uniformity. The new perforated diaphragm sensors were fully functional with sensitivities ranging from 23 to 252 μV/V-kPa (FSO = 5–80 mV), and show a higher nonlinearity at elevated pressures than identical sensors with solid diaphragms. Sensors (1.5 × 1.5 mm 2) with perforated diaphragms (pores = 40 μm) have a nonlinearity of approximately 10% while for the identical solid diaphragm sensor it was roughly 3% over the entire 200 kPa range. This is the first time piezoresistive pressure sensors with integrated diffusion pores for detection of hydrogel swelling pressure have been fabricated and tested.