A new torque transfer standard using metallic TBTF resonant sensor was developed to overcome the overload capability problem which occurs with conventional metallic resistance strain gauges. Previous research work, however, has shown that the first prototype of the metallic TBTF resonant sensor was not suitable for use in a torque transfer standard due to its size and subsequent sensitivity to parasitic lateral forces. To maximize the benefits from this sensor, particularly overload capability and long-term stability, in the high accuracy torque measurement application area, there is a need to develop significantly smaller devices. The aim of this thesis is to research through FEA modelling and experimental characterisation the key performance parameters required to produce a miniaturised metallic TBTF resonant sensor that provides better performance when applied in a torque measurement system. For high accuracy any torque transducer using these sensors ought to have low sensitivity to parasitic influences such as bending moments and lateral forces, which can only be achieved with reduced size. The problems with the existing design, key design issues, possible configuration and packaging solutions of the metallic TBTF resonant sensor that could be used for achieving a higher accuracy torque transfer standard are considered. Two designs of miniaturised metallic TBTF resonant sensors, SL20 and SL12, are considered and experimentally investigated. The lateral forces are reduced by 52% for SL20 design and by 80% for SL12 design when compared to the original SL40 design. A torque transducer using the SL20 design was calibrated falling into the Torque Transfer Standard class of accuracy 1 category, uncertainty 0.8%. A torque transducer using the SL12 design was made and calibration showed a class of accuracy 0.5 category, uncertainty 0.2%. The results from this research indicate that the SL12 design is suitable for use in a torque transfer standard. The SL12 design is optimal and the smallest size possible based on the overload capability design criteria requiring the tine cross sectional area to remain constant.

The steel through-truss Traffic Bridge, located in Saskatoon, Saskatchewan is over one hundred years old. The bridge has been subject to ongoing maintenance throughout its service life. However, inspection reports from 2005 and 2006 highlighted the severe deterioration experienced primarily by the steel members immediately above and below the deck surface. These reports prompted the City of Saskatoon (COS) to implement a rehabilitation project that involved the installation of a post-tensioning system to relieve the badly corroded bottom chord members of the axial loads due to the self-weight of the structure, in 2006. Due to the severe deterioration and the structural modifications that the Traffic Bridge has endured, a limited scope structural health monitoring (SHM) system, based on strain measurements, was implemented to reduce some of the uncertainty regarding the active load paths occurring at the deck level.<p> The objectives of the SHM study were to obtain more information regarding the actual load paths and ascertain possible types of structural redundancy, to determine how to best model this type of structure, and to find ways to track ongoing deterioration using instrumentation. The SHM study involved controlled truck loading scenarios to permit measurement of the load paths and provide data to compare the measured results to a finite element (FE) model of the instrumented span. In addition, random loading scenarios were used to capture the vertical dynamic response of the structure in order to further refine the FE model.<p> This study focused on the response of one-half of one interior span. A total of 72 strain gauges were installed. The downstream truss was highly instrumented at ten locations, three members of the upstream truss were instrumented to measure the distribution, and the floor joists in the downstream lane were instrumented to establish possible redundancy paths.<p> Using an FE model in combination with the measured strain data, it was found that redundant load paths only existed at the level of the deck. The bottom chord members experienced non-zero strains once the control vehicle was past the span, possibly indicating some level of redundancy. The members believed to relieve a portion of the bottom chord tensile forces included the car joists, edge joists, and the timber deck. The amount of force transferred from the bottom chord to the deck members was found by FE analysis to be highly related to the lateral stiffness of the floor beams.<p> The FE model was adjusted to match the measured results by modifying various modelling parameters. The most important features of the model were that all deck elements were modelled to be located at the elevation of the bottom chord, that the lateral stiffness of the floor beams was reduced by 50% to best represent the transfer of forces to deck elements, and that the stiffness of bottom chord members was reduced to 80% of their pristine values. In combination with calibrated modification factors applied to the measured values, this FE model is believed to be a useful tool to represent the behaviour of the structure to assist in detecting further damage by modelling the strain differential between members, and components of members.

The steel through-truss Traffic Bridge, located in Saskatoon, Saskatchewan is over one hundred years old. The bridge has been subject to ongoing maintenance throughout its service life. However, inspection reports from 2005 and 2006 highlighted the severe deterioration experienced primarily by the steel members immediately above and below the deck surface. These reports prompted the City of Saskatoon (COS) to implement a rehabilitation project that involved the installation of a post-tensioning system to relieve the badly corroded bottom chord members of the axial loads due to the self-weight of the structure, in 2006. Due to the severe deterioration and the structural modifications that the Traffic Bridge has endured, a limited scope structural health monitoring (SHM) system, based on strain measurements, was implemented to reduce some of the uncertainty regarding the active load paths occurring at the deck level.<p> The objectives of the SHM study were to obtain more information regarding the actual load paths and ascertain possible types of structural redundancy, to determine how to best model this type of structure, and to find ways to track ongoing deterioration using instrumentation. The SHM study involved controlled truck loading scenarios to permit measurement of the load paths and provide data to compare the measured results to a finite element (FE) model of the instrumented span. In addition, random loading scenarios were used to capture the vertical dynamic response of the structure in order to further refine the FE model.<p> This study focused on the response of one-half of one interior span. A total of 72 strain gauges were installed. The downstream truss was highly instrumented at ten locations, three members of the upstream truss were instrumented to measure the distribution, and the floor joists in the downstream lane were instrumented to establish possible redundancy paths.<p> Using an FE model in combination with the measured strain data, it was found that redundant load paths only existed at the level of the deck. The bottom chord members experienced non-zero strains once the control vehicle was past the span, possibly indicating some level of redundancy. The members believed to relieve a portion of the bottom chord tensile forces included the car joists, edge joists, and the timber deck. The amount of force transferred from the bottom chord to the deck members was found by FE analysis to be highly related to the lateral stiffness of the floor beams.<p> The FE model was adjusted to match the measured results by modifying various modelling parameters. The most important features of the model were that all deck elements were modelled to be located at the elevation of the bottom chord, that the lateral stiffness of the floor beams was reduced by 50% to best represent the transfer of forces to deck elements, and that the stiffness of bottom chord members was reduced to 80% of their pristine values. In combination with calibrated modification factors applied to the measured values, this FE model is believed to be a useful tool to represent the behaviour of the structure to assist in detecting further damage by modelling the strain differential between members, and components of members.

Decadal variations in climate are important, because the magnitude of sustained decadal change is often much larger than the often discussed background trends. Climate variability at interannual and longer periods is most often discussed in the context of climate modes defined by sea level pressure (SLP) and sea surface temperature (SST) patterns. However, SLP and SST are not capable descriptors of ocean dynamics. The approximately two decades of global sea surface height (SSH) measurements from satellite altimetry reveal substantial low-frequency redistributions of heat and salt in the ocean, which may or may not be related to defined climate modes. In addition, coastal sea level responds directly to synoptic variability in the atmosphere, providing long records of weather events in coastal areas. The unifying idea in the following analyses is the value and versatility of SSH from altimetry and sea level from tide gauges for investigations of decadal climate variability. Three applications of SSH and coastal sea level to the study of decadal change demonstrate the merits of using sea level for investigations of oceanic and atmospheric, episodic and continuous processes. The analyses concern a multidecadal change in storminess along the coast of the Southeast U.S., basin-scale coherent sea level variations in the western boundary of the North Atlantic, and the low-frequency response of the ocean to atmospheric forcing in the Northeast Pacific.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22256号 / 理博第4570号 / 新制||理||1656(附属図書館) / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)准教授 西村 卓也, 教授 福田 洋一, 准教授 深畑 幸俊 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

The dissertation thesis deals with the determination of uncertainty of strain measurement and the stress using resistance strain gages. You can find two methods to define the uncertainty in the thesis, GUF and MMC, and both are applied for measurements carried out with resistance strain gages. Definition of the measurement uncertainty was set for the strain measured by uniaxial and biaxial strain gages. The uncertainty of the stress was defined for linear strain gages, T Rosettes and Rosettes. There were universal mathematic-technical models defined to measure strain and stress, these models can be used either for standard and special measurements i.e. high-temperature, or for measurements in radiation field. Each part of the strain uncertainty and stress is analyzed from the point of view of a size of uncertainty and a form of probability of the function that strain and stress can adopt. The maximum focus was dedicated to the mistakes influencing measured strain like strain gage properties, installation and operating influences, external influences, time effects and the influence of the measured object. There are two mistakes influencing the stress described and analyzed in the thesis, the mistake of the Young’s modulus of elasticity and the mistake of the Poisson’s ratio. The thesis is conceived as a complex of information related to the measurement uncertainties using the resistance strain gages and methods of defining the measurement uncertainty in a way that the experimenter can apply the gained info and methods in the required measurements. The final chapters give representative examples to define measurement uncertainties for uniaxial and biaxial stress applying GUF and MMC method. The thesis also includes the experiment that compares measured values of strain, stress and measurement uncertainties, using several different types of strain gages at different temperatures, with theoretical calculation of strain and with stress. The experiment was carried out using the displacement sensor that works on an elementary principle of bending load.

The thesis is focused on experimental load definition of an aircraft. Especially is measured bending moment is measured on wing during the flight. The thesis includes theoretical basis for strain gauge measurements and procedure of statistic evaluation. For each of flight maneuvers, there are theoretical wing loads calculated and then the values are compared. The end of the thesis shows proposals for improvement of used method of flight possible repeated measurement.

The purpose of this diploma thesis was design and realisation of measuring system, enabling measuring forces between climber´s feet and holds on the climbing wall and using this measu-red values during a training of sport climber. In this thesis there are discovered possibilities about constructing this system and determina-ted basic requirements of measuring. There are also stated principles of application the strain gauges for measuring the tension. Descriptions of developping specific sensors, hardware interface and PC application are also part of this thesis. Constructed system was used for mea-suring climbers and values were analysed by using the application.

Calibration is assesment dependencies test data on values etalon. Work suggests optimum calibration routes inclusive uncertainties metering.

A torque transducer or a torque sensor is a device for measuring and recording the torque on a rotating system. Torque transducers usually employ strain gauges to measure the torsional moment applied to a rotating shaft.It is to be noted that for an ideal torque transducer, it should measure only the strain that is caused by a torque. Strain due to bending load should be compensated as per the Wheatstone bridge arrangement. However, because of geometrical tolerances and assembly errors, the compensation doesn’t occur and the measured strain is a resultant of bending loads and axial loads which are undesired to measure the torque associated with the system. An analytical formulation has been developed using Matlab and this thesis gives the generalized indication of the strain due to all the associated loads. The user shall also entire the region where the strain needs to be computed and this knowledge can be useful for placing the strain gauges in the shaft accordingly. Initially, the formulation is based on a standard Torque Transducer used at Atlas Copco and then, a generalized result has been developed. The theoretical formulation is verified using the ProEngineer Mechanica software. The end user shall enter the different loads (if any) along with the geometrical tolerance values and the output will be an indication of the strain at point, strain at a region and sensitivity. The main intention of the thesis is to create a better understanding of the strain associated with the twisting, bending and axial loads and also the geometrical imperfections. The user can also make a decision on the location of strain gauges on a shaft for maximum accuracy. Finally, the differences in error from different possible configurations are compared and a conclusion has been made based on factorial design pertaining to design of experiments. / Momentgivare är små sensorer som används för att mäta och registrera vridmomentet på en roterande axel. Momentgivare baseras vanligtvis på trådtöjningsmätare för att mäta vridmomentetet kring axeln de är fixerade på. Det skall noteras att en ideal momentgivare endast bör mäta den yttöjning som uppkommer på grund av ett vridmoment. Den belastning som uppkommer på grund av axelns böjning kompenseras bort med hjälp av en Wheatstonebrygga. Men på grund av geometriska toleranser och monteringsfel kan kompensationen bli felaktig och då påverkas det uppmätta momentet även av böj och axialbelastningar vilket är oönskat. En analytisk modell har utvecklats med hjälp av Matlab och denna rapport undersöker de olika lastfallens bidrag till momentfelet. Användaren kan ange området där yttöjningen skall beräknas och utifrån de beräkningarna bestämma var trådtöjningsgivarna bör placeras. Inledningsvis är beräkningarna baserade på en av Atlas Copcos momentgivare och sedan har generaliserade resultat utvecklats. De teoretiska beräkningarna verifieras med hjälp av programmet ProEngineer Mechanica. Användaren kan ange vilka belastningar som axeln känner samt de geometriska toleransvärdena och modellen beräknar då ytspänningen för den valda regionen. Det huvudsakliga syftet med denna avhandling är att skapa en bättre förståelse av ytspänningen som uppkommer på grund av vridning, böjning och axiella belastningar och även geometriska imperfektioner. Modellen kan också användas för att göra beräkningar som visar var töjningsgivare bör placeras på axeln för maximal precision. Slutligen har de introducerade felet från de olika möjliga konfigurationerna jämförts och en slutsats har dragits baserat på faktorförsök.