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This dissertation presents design challenges and promising solutions for temperature and pressure sensors which are highly desirable for harsh-environment applications, such as turbine engines. To survive the harsh environment consisting of high temperatures above 1000°C, high pressures around 300 psi, and corrosive gases, the sensors are required to be robust both electrically and mechanically. In addition, wire connection of the sensors is a challenging packaging problem, which remains unresolved as of today. In this dissertation, robust ceramic sensors are demonstrated for both high temperature and pressure measurements. Also, the wireless sensors are achieved based on microwave resonators. Two types of temperature sensors are realized using integrated resonator/antennas and reflective patches, respectively. Both types of the sensors utilize alumina substrate which has a temperature-dependent dielectric constant. The temperature in the harsh environment is wirelessly detected by measuring the resonant frequency of the microwave resonator, which is dependent on the substrate permittivity. The integrated resonator/antenna structure minimizes the sensor dimension by adopting a seamless design between the resonator sensor and antenna. This integration technique can be also used to achieve an antenna array integrated with cavity filters. Alternatively, the aforementioned reflective patch sensor works simultaneously as a resonator sensor and a radiation element. Due to its planar structure, the reflective patch sensor is easy for design and fabrication. Both temperature sensors are measured above 1000°C. A pressure sensor is also demonstrated for high-temperature applications. Pressure is detected via the change in resonant frequency of an evanescent-mode resonator which corresponds to cavity deformation under gas pressure. A compact sensor size is achieved with a post loading the cavity resonator and a low-profile antenna connecting to the sensor. Polymer-Derived-Ceramic (PDC) is developed and used for the sensor fabrication. The pressure sensor is characterized under various pressures at high temperatures up to 800°C. In addition, to facilitate sensor characterizations, a robust antenna is developed in order to wirelessly interrogate the sensors. This specially-developed antenna is able to survive a record-setting temperature of 1300°C.

Researchers performed 35 full-scale lateral load tests on piles driven within the reinforcement zone of a mechanically stabilized earth wall (MSE wall). Data defining the induced tensile force on the reinforcements during lateral pile loading was used to develop multi-linear regression equations to predict the induced tensile force. Equations were developed by previous researchers that did not consider the diameter of the pile, the fixed head condition, relative compaction, or cyclic loading. The purpose of this research was to include this tensile force data and develop prediction equations that considered these variables. Additionally, a full-scale lateral load test was performed for a 24-inch diameter pipe pile loaded against a 20-inch width square pile. The test piles were instrumented using load cells, string potentiometers, LVDTs, strain gauges and hybrid pressure sensors. The lateral load tests were used to evaluate the ability of finite difference (LPILE) and finite element (PLAXIS3D) models to compute results comparable to the measured results. The results of this analysis showed that the diameter of the pile is a statistically significant variable for the prediction of induced tensile force, and the induced tensile force is lower for piles with larger diameter. Fixed head conditions have no effect on the prediction of induced tensile force. Cyclic loading had minimal impact on the prediction of induced tensile force, but relative compaction did have an important statistical significance. Therefore, prediction equations for induced tensile force in welded wire were developed for relative compaction less than 95 percent and relative compaction greater or equal than 95 percent. A general prediction equation (Eq. 3-4) was developed for ribbed-strip reinforcements that included the effect of pile diameter and larger head loads. With 1058 data points, this equation has an R2 value of 0.72. A general prediction equation (Eq. 3-9) was also developed for welded-wire reinforcements that included data from cyclic and static loading, fixed and free head conditions, and relative compaction for 12-inch wide piles with a higher range of pile head loads. This equation based on 2070 data points has an R2 value of 0.72. The prediction equations developed based on all the available data are superior to equations developed based on the original set of field tests. The finite element models produced results with good agreement with pipe pile measurements while the finite difference model showed better agreement with the square pile measurements. However, for the denser backfills involved, back-calculated soil properties were much higher than would be predicted based on API correlations. The API equations are not well-calibrated for dense granular backfills.

This report describes a simple mechanical system developed for producing dynamic pressures of up to 50 kPa from zero-to-peak and over the frequency range 0-58 Hz. The system is constructed for dynamic calibration of pressure sensors and consists of an open tube, 30 cm in height, mounted vertically on the support plate. The support plate is connected to the vibration exciter which is driven by a piston, a connecting rod, disc and axle, and an electric motor. The pressure  sensor to be calibrated is mounted vertically at the bottom of the open tube so that the diaphragm of the sensor is in contact with the working liquid in the tube. When the system is started, the motion of the piston provides a sinusoidal movement to the open tube and calibration is achieved. The different parts of the system are designed using NX Siemens. MatLab is used to determine the results and graphs from the equations derived. The analysis shows that the displacement, velocity, and acceleration of the system are highly affected by the distance between the disc centre and the disc pin, and the rotational speed of the system. The length of the connecting rod does not affect the displacement and barely affects the velocity and acceleration of the system. The total force, torque, and power of the system is utilized to select the electric motor and the frequency inverter. / Denna rapport beskriver ett enkelt mekaniskt system som utvecklas för att producera dynamiska tryck upp till 50 kPa från noll-till-topp och över frekvensområdet 0-58 Hz. Systemet är konstruerat för dynamisk kalibrering av trycksensor och består av öppet rör 30 cm höjd monteras vertikalt på stödplattan. Stödplattan är ansluten till vibrationsexcite dvs, den yttre cylindern som drivs av en kolv, en vevstake, skiva och axel och en elmotor. Trycksensorn som skall kalibreras är monterad vertikalt vid botten av det öppna röret så att membranet hos sensorn är i kontakt med arbetsvätskan i röret. När systemet startas, ger rörelsen hos kolven som ger vibrationer till det öppna röret och kalibrering uppnås. De olika delarna av systemet är utformade med hjälp av NX Siemens. MatLab används för att bestämma resultaten och diagram härledda från ekvationerna. Analysen visar att den förskjutning, hastighet och acceleration av systemet är i hög grad påverkade av avståndet mellan skivans centrum och skivtappen, och rotationshastigheten hos systemet. Längdn av vevstaken påverkar inte försjutningen och påverkar knappt hastigheten och accelerationen hos systemet. Den totala kraften, vridmomentet och kraften i systemet användes för attvälja de andra komponenterna i systemet dvs, den elektriska motorn och frekvensomvandlaren.

Ultradünne Gläser (engl. Ultra Thin Glass – UTG) sind ab einer Glasdicke von 25 μm industriell herstellbar und verfügen über eine mechanische Flexibilität. Außerdem hat Glas in Abhängigkeit der Glassorte das Potenzial, eine gute chemische und thermisch Beständigkeit sowie gute elektrische Eigenschaften zu besitzen, wodurch es als Sub-stratmaterial für die Aufbau- und Verbindungstechnik der Elektronik geeignet ist. Der-zeit wächst die Anzahl am Markt verfügbarer ultradünner Gläser und durch bereits entwickelte Rolle zu Rolle (R2R) Anlagen ist eine industrielle Verarbeitung von UTG realisierbar. Um Glas, im Speziellen ultradünnes Glas, in der Aufbau- und Verbindungstechnik der Elektronik als Substratmaterial zu nutzen, wird die Anwendung interdisziplinärer Me-thoden notwendig. Durch die vorliegende Arbeit wird ein Überblick verschiedener Verfahren vorgestellt und ausgewählte Verfahren getestet, welche für die Herstellung von UTG-basierter, hochtemperaturfähiger (HT-fähiger) Schaltungsträger und/oder Sensorik notwendig sind. Abgedeckt wird das gesamte Spektrum beginnend bei der Konfektionierung und Bearbeitung über die Funktionalisierung bzw. die Funktions-schichtabscheidung, die Erzeugung HT-fähiger elektrischer Verbindungen bis hin zur Herstellung und den Test von Demonstratoren in Form von Druck- und Kraftsenso-ren. / Ultra Thin Glasses (UTG) can be produced industrially from a thickness of 25 μm and are mechanically flexible. Furthermore, glass has the potential to have a good chemi-cal and thermic persistence (depending on the type of glass) as well as good electrical characteristics, which makes it interesting as a material to use for the packag-ing of integrated circuits of electronics. Currently, the amount of ultra-thin glasses on the market is rising and roll to roll systems (R2R) allow an industrial processing of UTG. For the use of glass, especially ultra-thin glass for the packaging of integrated circuits of electronics, the use of interdisciplinary methods is needed. This thesis will give an overview over different procedures of which some selected ones, that are essential for the production of UGT-based, high-temperature (HT) resistant circuit carrier and/or sensor technology, will be tested. In doing so, the whole range will be covered: from packaging and processing to the functionalisation or functional layer disposition and the creation of HT-capable electrical connection as well as the production and testing of demonstration systems in the form of pressure sensors and force sensors.

No description available.

No description available.

Pressure measurements are required in various industrial applications, including extremely harsh environments such as turbine engines, power plants and material-processing systems. Conventional sensors are often difficult to apply due to the high temperatures, highly corrosive agents or electromagnetic interference (EMI) noise that may be present in those environments. Fiber optic pressure sensors have been developed for years and proved themselves successfully in such harsh environments. Especially, diaphragm based fiber optic pressure sensors have been shown to possess advantages of high sensitivity, wide bandwidth, high operation temperature, immunity to EMI, lightweight and long life. Static and dynamic pressure measurements at various locations of a gas turbine engine are highly desirable to improve its operation and reliability. However, the operating environment, in which temperatures may exceed 600 °C and pressures may reach 100 psi (690 kPa) with about 1 psi (6.9kPa) variation, is a great challenge to currently available sensors. To meet these requirements, a novel type of fiber optic engine pressure sensor has been developed. This pressure sensor functions as a diaphragm based extrinsic Fabry-Pérot interferometric sensor. One of the unique features of this sensor is the all silica structure, allowing a much higher operating temperature to be achieved with an extremely low temperature dependence. In addition, the flexible nature of the sensor design such as wide sensitivity selection, and passive or adaptive temperature compensation, makes the sensor suitable for a variety of applications An automatically controlled CO₂ laser-based sensor fabrication system was developed and implemented. Several novel bonding methods were proposed and investigated to improve the sensor mechanical ruggedness and reduce its temperature dependence. An engine sensor testing system was designed and instrumented. The system generates known static and dynamic pressures in a temperature-controlled environment, which was used to calibrate the sensor. Several sensor signal demodulation schemes were used for different testing purposes including a white-light interferometry system, a tunable laser based component test system (CTS), and a self-calibrated interferometric-intensity based (SCIIB) system. All of these sensor systems are immune to light source power fluctuations, which offer high reliability and stability. The fiber optic pressure sensor was tested in a F-109 turbofan engine. The testing results prove the sensor performance and the packaging ruggedization. Preliminary laboratory and field test results have shown great potential to meet not only the needs for reliable and precise pressure measurement of turbine engines but also for any other pressure measurements especially requiring high bandwidth and high temperature capability. / Ph. D.

Measurement of physical parameters in harsh environments (high pressure, high temperature, highly corrosive, high electromagnetic interference) is often desired in a variety of areas, such as aerospace, automobile, energy, military systems, and industrial processes. Pressure and temperature are among the most important of these parameters. A typical example is pressure monitoring in jet engine compressors to help detect and control undesirable air flow instabilities, namely rotating stall and surge. However, the temperatures inside a compressor could reach beyond 600°C for today's large engines. Current fiber-optic sensor can operate up to about 300°C and even the most widely employed semiconductor sensors are limited below 500°C. The objective of this research is to push the limit of fiber-optic sensing technology in harsh environment applications for both pressure and temperature measurements by developing novel sensing structures, fabrication techniques, and signal processing algorithms. An all-fused-silica pressure sensor has been demonstrated which is fabricated on the tip of a fiber with a diameter no larger than 125μm. The sensor was able to function beyond the current limit and operate into the 600~700°C range. Also a temperature sensor has been developed using sapphire fibers and wafers for ultra-high temperature measurement as high as 1600°C. This effort will generate more understanding regarding sapphire fiber's high temperature properties and could possibly lead to novel designs of pressure sensor for beyond 1000°C. Both sensors have been field tested in real-world harsh environments and demonstrated to be reliably and robust. In this dissertation, the design, fabrication, and testing of the sensors are discussed in detail. The system and signal processing techniques are presented. The plan and direction for future work are also suggested with an aim of further pushing the operating limit of fiber-optic sensors. / Ph. D.

A technology for fabricating fiber optic pressure sensors is described. This technology is based on intermediate-layer bonding of a fused silica ferrule to a patterned, micro-machined fused silica diaphragm, providing low temperature fabrication of optical pressure sensor heads that can operate at high temperature. Fused silica ferrules and fused silica diaphragms are chosen to reduce the temperature dependence. The fused silica diaphragms have been micro-machined using wet chemical etching in order to form extrinsic Fabry-Perot (FP) interferometric cavities. Sol-gel is used as an intermediate-layer for both fiber-ferrule bonding and ferrule-diaphragm bonding at relatively low temperature (250 °C). The pressure sensors fabricated in the manner can operate at temperatures as high as 600 °C. The self-calibrated interferometric-intensity-based (SCIIB) technology, which combines fiber interferometry and intensity-based sensing method into a single sensor system, is used to test and monitor the pressure sensor signal. The light returned from the FP cavity is split into two channels. One channel with longer coherence length can test the effective interference generated by the FP cavity, while the other channel with shorter coherence length can get signal proportional only to the source power, fiber attenuation, and other optical losses. The ratio of the signals from the two channels can compensate for all unwanted factors, including source power variations and fiber bending losses. [11] / Master of Science