• Journal of the Semiconductor & Display Technology
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• v.14 no.2
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• pp.1-7
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• 2015

In this paper, a new capacitive pressure sensor has been proposed for a displacement measurement. The new sensor is mainly composed of a gap of $5{\mu}m$ and a notch of $1{\mu}m$. And the sensor has the performance as the high sensitivity and capacitance compared with a commercial capacitive sensor. Therefore, the advantages of the new capacitive pressure sensor are good sensitivity in normal range, mechanically robust and large overload protection. The analytical model is induced for confirming the performance of the proposed sensor. In addition, FEM (finite elements method) simulation has been performed to verify the analytical model. Firstly, the displacement characteristics of diaphragm membrane were simulated by the analytical model and FEM in the case of different structure and materials. At last, through this analysis, these simulation results can be predicted the change of the performance when the device parameters are varied. And it is used as a design tool to achieve at a set of performance we desired.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.10a
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• pp.153-160
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• 1995

Mixed finite element formulations for incompressible materials show pressure oscillations or pressure modes in four-node quadrilateral elements. The criterion for the stability in the pressure solution is the so-called Babufka-Brezzi stability condition, and the four-node elements based on mixed variational principles do not appear to satisfy this condition. In this study, a pressure continuity residual based on the pressure discontinuity at element edges is used to study the stabilization of pressure solutions in bilinear displacement-constant pressure four-node quadrilateral elements. It is shown that the pressure solutions, although stable, exhibit sensitivity to the stabilization parameters.

• Wind and Structures
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• v.10 no.1
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• pp.23-44
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• 2007

Wind tunnel experiments on small scale groups of tanks are reported in the paper, with the aim of evaluating the pressure patterns due to group effects. A real tank configuration is studied in detail because one tank buckled during a hurricane category 3. Three configurations are studied in a wind tunnel, two with several tanks and different wind directions, and a third one with just one blocking tank. The pressures were measured in the cylindrical part and in the roof of the tank, in order to obtain pressure coefficients. Next, computational buckling analyses were carried out for the three configurations to evaluate the buckling pressure of the target structure. Finally, imperfection-sensitivity was investigated for one of the configurations, and moderate sensitivity was found, with reductions in the maximum load of the order of 25%. The results help to explain the buckling of the tank for the levels of wind experienced during the hurricane.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.10-13
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• 2006

This paper describes on the fabrication and characteristics of a 3C-SiC (Silicon Carbide) micro pressure sensor for harsh environment applications. The implemented micro pressure sensor used 3C-SiC thin-films heteroepitaxially grown on SOI (Si-on-insulator) structures. This sensor takes advantages of the good mechanical properties of Si as diaphragms fabricated by D-RIE technology and temperature properties of 3C-SiC piezoresistors. The fabricated pressure sensors were tasted at temperature up to $250^{\circ}C$ and indicated a sensitivity of 0.46 mV/V*bar at room temperature and 0.28 mV/V*bar at $250^{\circ}C$. The fabricated 3C-Sic/SOI pressure sensor presents a high-sensitivity and excel lent temperature stability.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1372-1374
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• 2001

This paper describes fabrication and characteristics of metal thin-film pressure sensor for working at high temperature. The proposed pressure sensor consists of a chrom thin-film, patterned on a Wheatstone bridge configuration, sputter-deposited onto thermally oxidized Si membranes with an aluminium interconnection layer. The fabricated pressure sensor presents a low temperature coefficient of resistance, high-sensitivity, low non-linearity and excellent temperature stability. The sensitivity is 1.097 $\sim$ 1.21 mV/V kgf/$cm^2$ in the temperature range of 25 $\sim$ $200^{\circ}C$ and the maximum non-linearity is 0.43 %FS.

• Journal of the Optical Society of Korea
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• v.17 no.4
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• pp.300-304
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• 2013

Novel breakthrough random-hole optical fibers (RHOFs) are fabricated in a draw tower facility, by tapering an optical fiber preform packed with a silica powder mixture capable of producing air holes in situ at the high temperature of tens of hundreds in degrees Celsius. Structural and propagation characteristics of the porous RHOF are explained briefly. Experimental investigations of the invented RHOF are performed for pressure sensor applications. Remarkable results are obtained for the RHOF with desirable pressure sensitivity independent of temperature, as is required for harsh conditions as in oil reservoirs.

• Journal of Sensor Science and Technology
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• v.33 no.1
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• pp.7-11
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• 2024

Soft-pressure sensors have numerous applications in soft robotics, biomedical devices, and wearable smart devices. Herein, we present a highly sensitive electronic skin device with an isotropic wrinkled pressure sensor. A conductive ink for soft pressure sensors is produced by a solution process using polydimethylsiloxane (PDMS), poly 3-hexylthiophene (P3HT), carbon black, and chloroform as the solvents. P3HT provides high reproducibility and conductivity by improving the ink dispersibility. The conductivity of the ink is optimized by adjusting the composition of the carbon black and PDMS. Soft lithography is used to fabricate a conductive elastic structure with an isotropic wrinkled structure. Two conductive elastic structures with an isotropic wrinkle structure is stacked to develop a pressure sensor, and it is confirmed that the isotropic wrinkle structure is more sensitive to pressure than when two elastic structures with an anisotropic wrinkle structure are overlapped. Specifically, the pressure sensor fabricated with an isotropic wrinkled structure can detect extremely low pressures (1.25 Pa). Additionally, the sensor has a high sensitivity of 15.547 kpa^-1 from 1.25 to 2500 Pa and a linear sensitivity of 5.15 kPa^-1 from 2500 Pa to 25 kPa.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.305-310
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• 2013

In this paper, the pressure sensor usable in a high temperature, using a SDB(silicon-direct-bonding) wafer of Si/$SiO_2$/Si-sub structure was provided and studied the characteristic thereof. The pressure sensor produces a piezoresistor by using a single crystal silicon as a first layer of SDB wafer, to thus provide a prominent sensitivity, and dielectrically isolates the piezoresistor from a silicon substrate by using a silicon dioxide layer as a second layer thereof, to be thus usable even under the high temperature over $120^{\circ}C$ as a limited temperature of a general silicon sensor. The measured result for a pressure sensitivity of the pressure sensor has a characteristic of high sensitivity, and its tested result for an output of the sensor further has a very prominent linearity and hysteresis characteristic.

• The Journal of the Acoustical Society of Korea
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• v.16 no.3
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• pp.73-80
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• 1997

This paper describes structural optimization of optical fiber-wound mandrel hydrophones with Finite Element Method (FEM). The hydrophone is supposed to have operation frequency range of up to 10 kHz and show omni-directional sensitivity pattern at 5 kHz. Studied parameters are mandrel geometry, molding thickness, and material properties of constitutional parts of the hydrophone. Theoretical calculation result shows that pressure sensitivity of the hydrophone increased as either mandrel length or molding thickness gets larger. Also higher pressure sensitivity requires a mandrel or molding material with relatively low Youngs modulus or Poissons ratio. Hydrophone bandwidth increases either as the mandrel length becomes shorter or as the mandrel becomes harder. The omni-directional characteristic is improved as the mandrel length becomes shorter, at 5 kHz. With the above results, we determine the structure of an optical fiber-wound mandrel hydrophone which has the pressure sensitivity of $30 {\times} 10_{-7}$ Rad./Pa, operation frequency range of up to 10 kHz, and shows omni-directional sensitivity pattern at 5 kHz.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.2
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• pp.113-128
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• 2004

To investigate major influencing factors on earth pressure acting on an arch-shaped cut and cover tunnel, Monte Carlo simulation based quantitative sensitivity analysis was carried out for mechanical properties of ground as well as excavation configuration-related design factors. From the sensitivity analysis, it was intended that effects of earth pressures from different influencing factors on a cut and cover tunnel should be numerically identified. Output factors used in the sensitivity analysis such as vertical and horizontal earth pressures at different tunnel positions were obtained from the finite element analysis. In this study, it was revealed that depending upon positions where horizontal as well as vertical earth pressures were acting, they were differently influenced by the same input factors. In addition, earth pressures acting an cut and cover tunnel depended mainly on the embankment at crown and the inclination of cut slope.