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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Data fusion of 3D profiles measured by projected fringe profilometry

Hsu, Yi-Ling 08 July 2005 (has links)
This paper presents a novel integration technique for segmented 3D profiles measured by projected fringe profilometry. Fringe patterns are projected to the inspected surface. The projected patterns fix their positions relative to the tested object during two segmented measurements. Thus, finding two matched surface points becomes a problem of searching for two identical phases in the fused data sets. This novel integration technique can match images successfully and achieve pixel-to-pixel registration easily even in the presence of geometric deformation, illumination changes, and severe occlusions. It is superior to the other methods because of its: (1) High matching accuracy; (2) Improved robustness; (3) Reduced computational time; (4) Capability of compensating distortions of the optical system at every pixel location; (5) Suitable for images rotating or scaling; and (6) Suitable for any other projected fringe measurement method. We also propose a method to design and fabricate a 2-D fringe pattern which can be applied to the integration technique for segmented 3D profiles. Campered with using 1-D fringe patterns for image registration, using a 2-D fringe pattern saves the measurement time and further proveds more tolerence to hand the shadow and noise problems. Tests of the system performance have been carried out that the accuracy of the registration scheme is 5.96% of image pixel size. Therefore, this technique can be extensively used in modern high technology industry. Especially when it requires higher resolution close-up images or overcomes the issue of not every inspected object can be fully expressed just by a single full-field measurement, it is necessary to use this integration technique.
2

Planning for Curved-Surface Milling and Surface Profile Measurement by Taguchi Method

Wang, Hsueh-o 30 June 2006 (has links)
ABSTRACT This research uses Taguchi Method, combined with Computer Aided Design and Manufacturing, processing the work piece into the saddle type. Next, diverse sampling methods are applied to measure the profile of surface with Coordinate Measuring Machine, with an aim to analyzing the main factors that influence cutting and seeking the last conditions for cutting out the curved surface; in addition, I will probe into the contribution rate of each factor which influences the precision during the process of measurement. The following results of this research are expected to be offered to the circles of vocational education as a basis of processing and measuring instruction. In this way, it will not take too much time to try and error and therefore, the practice course can be more efficient. 1. With reference to the documents that are focused on the factors affecting the cutting, this thesis, by means of Taguchi Method, shows that during the process of cutting saddle-type curved surface, the rotating speed of the axle is the most influential, whose contribution rate is 59.38%. 2. Since most documents are on circles, balls or cone objects, this thesis will aim at the measurement of saddle-type curved surface, with an intention to further the measuring technique. 3. It is found that as to the saddle-type curved surface, random sampling can get the profile of surface with minimal errors, and has no such trouble as using HSS or LHS, which can reduce time and cost. 4. In the experiment of Taguchi Method, according to analysis of variance, the influence of the sampling area is the greatest while the choice of sampling method only contributes to 3.46%.
3

Road Surface Measurement and Multi-Scale Modeling of Rubber Road Contact and Adhesion

Motamedi, Mohammad 07 October 2015 (has links)
A major challenge in tire, as well as in road engineering, is to understand the intricate mechanisms of friction. Pavement texture is a feature of the road surface that determines most tire-road interactions, and can be grouped into two classes: macro-texture, resulting mainly in the hysteretic component of friction, and micro-texture, resulting in adhesion. If both textures are maintained at high levels, they can help provide sufficient resistance to skidding. The ultimate objective of this research is to develop a physics-based multiscale rubber-road friction model that can predict the effectiveness of the tire as it interacts with the vehicle and the pavement. The model is developed based on sound physics and contact mechanics theories and uses road profile measurements and data measured on various tire compounds. To be able to predict road surface characteristics, it is proven that road surfaces are of fractal nature on given ranges of scale. It is shown that while global fractal quantities fail to classify pavement profiles, a local fractal parameter and three other texture parameters can separate road profiles that have different friction characteristics. Through the implementation of various contact theories and by conducting simulation studies, a methodical understanding of contact mechanics and of the effect of the diverse factors that influence friction is attained. To predict the viscoelastic friction between any given tire tread compound and road, the Nanovea JR25 portable optical profilometer is used to measure the road profiles. To characterize the road profile, the one-dimensional pavement measurements are used to obtain the two-dimensional power spectrum, followed by testing and characterizing the tread compounds (this is being carried out by Bridgestone). This data is used to develop a comprehensive analytical methodology to predict friction. To validate this model, a Dynamic Friction Test apparatus is designed and built. The friction tester enables measurement of the friction between tread compound samples and arbitrary surfaces, at different slip ratios. The correlations between the simulations and both indoor and outdoor experimental results are investigated. / Ph. D.
4

Electro-optic diagnostic techniques for the CLIC Linear Collider

Pan, Rui January 2015 (has links)
One of the most promising devices to provide accurate measurement of the longitudinal bunch profile at the tens of femtosecond level is based on electro-optic techniques. In this thesis, a bunch profile monitor, based on electro-optic spectral decoding (EOSD), is currently developed for the CLIC Test Facility 3 at CERN. The monitor is optimised for bunch lengths over 3.5 ps with effective window of 16 ps, and sub-picosecond resolution. The measurement results from the EO monitor are compared with measurements by coherent transition radiation on a streak camera. The measurement on bunch charge dependence is studied. Timing resolution of the bunch profile monitor is studied in both theory and numerical calculation. This thesis summarises a frequency analysis approach of electro-optic effect based on $\chi^{(2)}$ frequency mixing process. From the theory analysed in frequency domain, a non-crossed polarization measurement includes all three of the probe laser background term, the linear term to Coulomb field and the quadratic term to Coulomb field. Three methods are induced based on this frequency analysis result to retrieve Coulomb field value which is emitted from electron beam. The measured 1.3 MV/m field strength agrees with calculation result. An experiment is designed to study the role of incident beam sizes and non-collinear incident beams in EO technique. Due to the phase matching process, the non-collinear angle of the incident beams induces a frequency dependent angular chirp in the beams emitted after the EO crystal. This frequency offset may lead to frequency loss in fibre coupling, and thus lead to bunch length broadening in a measurement for short electron bunch.
5

Měření parametrů axiálních ložisek 2D triangulační technikou / Measurement of axial bearing parameters by 2D triangulation technique

Schrötter, Ján January 2018 (has links)
The goal of this diplma thesis is to design a system for axial bearings parameter measurement. The system uses principles of 2D active optical triangulation. The system will have a capability of compensating error caused by refraction on preservative oil layer, which the bearings are covered in.
6

Artificial intelligence based deconvolving on megavoltage photon beam profiles for radiotherapy applications

Weidner, Jan, Horn, Julian, Kabat, Christopher Nickolas, Stathakis, Sotirios, Geissler, Philipp, Wolf, Ulrich, Poppinga, Daniela 04 May 2023 (has links)
Objective. The aim of this work is an AI based approach to reduce the volume effect of ionization chambers used to measure high energy photon beams in radiotherapy. In particular for profile measurements, the air-filled volume leads to an inaccurate measurement of the penumbra. Approach. The AI-based approach presented in this study was trained with synthetic data intended to cover a wide range of realistic linear accelerator data. The synthetic data was created by randomly generating profiles and convolving them with the lateral response function of a Semiflex 3D ionization chamber. The neuronal network was implemented using the open source tensorflow.keras machine learning framework and a U-Net architecture. The approach was validated on three accelerator types (Varian TrueBeam, Elekta VersaHD, Siemens Artiste) at FF and FFF energies between 6 MV and 18 MV at three measurement depths. For each validation, a Semiflex 3D measurement was compared against a microDiamond measurement, and the AI processed Semiflex 3D measurement was compared against the microDiamond measurement. Main results. The AI approach was validated with dataset containing 306 profiles measured with Semiflex 3D ionization chamber and microDiamond. In 90% of the cases, the AI processed Semiflex 3D dataset agrees with the microDiamond dataset within 0.5 mm/2% gamma criterion. 77% of the AI processed Semiflex 3D measurements show a penumbra difference to the microDiamond of less than 0.5 mm, 99% of less than 1 mm. Significance. This AI approach is the first in the field of dosimetry which uses synthetic training data. Thus, the approach is able to cover a wide range of accelerators and the whole specified field size range of the ionization chamber. The application of the AI approach offers an quality improvement and time saving for measurements in the water phantom, in particular for large field sizes
7

Analytical Modeling for Sliding Friction of Rubber-Road Contact

Vadakkeveetil, Sunish 25 April 2017 (has links)
Rubber friction is an important aspect to tire engineers, material developers and pavement engineers because of its importance in the estimation of forces generated at the contact, which further helps in optimizing tire and vehicle performances, and to estimate tire wear. It mainly depends on the material properties, contact mechanics and operating condition. There are two major contributions to rubber friction, due to repeated viscoelastic deformation from undulations of surface called hysteresis and due to Vander Waals interaction of the molecules called adhesion. The study focuses on analytical modeling of friction for stationary sliding of rubber block on rough surfaces. Two novel approaches are discussed and compared. Frictional shear stress is obtained from the energy dissipated at the contact interface due to the elastic deformations of rubber block at different length scales. Contact mechanics theories based on continuity approach combined with stochastic processes to estimate the real contact area, mean penetration depth and true stresses at contact depending on operating conditions. Rubber properties are highly temperature dependent. Temperature model developed based on heat diffusion relation is integrated to consider the effects of temperature rise due to frictional heating. Model results are validated with theoretical results of literature. Simulation results of friction model is obtained for Compound A sliding on rough surface. Material properties are obtained using Dynamic Mechanical Analysis and Time temperature superposition. Influence of the friction models under different conditions are discussed. Model results are validated with experimental data from Dynamic friction tester on a 120-grit surface followed by future works. / Master of Science / Friction is a complex phenomenon that occurs in all tribological application. It is termed as the ratio of the shear force resisting the motion of the component to the normal force acting on the component. Microscopic observation has observed the importance of the effective contact area and roughness of the substrates in the influence of the friction. Rubber friction is an important aspect to tire engineers, material developers and pavement engineers because of its importance in the estimation of forces generated at the contact, which further helps in optimizing tire and vehicle performances, and to estimate tire wear. Because of the viscoelastic nature of rubber, the friction in rubber is much more complicated than observed for elastic materials and hence depends on the material properties apart from contact mechanics and operating condition. There are two major contributions to rubber friction, due to repeated viscoelastic deformation from undulations of surface called hysteresis and due to Vander Waals interaction of the molecules called adhesion. The study focuses on analytical modeling of friction for stationary sliding of rubber block on rough surfaces. Two novel approaches are discussed and compared. Frictional shear stress is obtained from the energy dissipated at the contact interface due to the elastic deformations of rubber block at different length scales. Contact mechanics theories based on continuity approach combined with stochastic processes to estimate the real contact area, mean penetration depth and true stresses at contact depending on operating conditions. Rubber properties are highly temperature dependent. Temperature model developed based on heat diffusion relation is integrated to consider the effects of temperature rise due to frictional heating. Model results are validated with theoretical results of literature. Simulation results of friction model is obtained for Compound A sliding on rough surface. Material properties are obtained using Dynamic Mechanical Analysis and Time temperature superposition. Influence of the friction models under different conditions are discussed. Model results are validated with experimental data from Dynamic friction tester on a 120-grit surface followed by future works.
8

腐食鋼板の力学特性評価のための板厚計測および有効板厚に関する考察

杉浦, 邦征, Sugiura, Kunitomo, 田村, 功, Tamura, Isao, 渡邊, 英一, Watanabe, Eiichi, 伊藤, 義人, Itoh, Yoshito, 藤井, 堅, Fujii, Katashi, 野上, 邦栄, Nogami, Kuniei, 永田, 和寿, Nagata, Kazutoshi, 岡, 扶樹, Oka, Tomoki 03 1900 (has links)
No description available.
9

Validation of hygrothermal material modelling under consideration of the hysteresis of moisture storage / Validierung hygrothermischer Materialmodellierung unter Berücksichtigung der Hysterese der Feuchtespeicherung

Scheffler, Gregor 09 April 2008 (has links) (PDF)
The achievable accuracy of hygrothermal building component simulation is significantly dependent on the applied material functions. These functions are determined by the material modelling marking the connection between the basic storage and transport parameters which are obtained from basic measurements, and the storage and transport coefficients which are defined within the balance and flow equations. It is the aim of the present study to develop a flexible and widely applicable material model which is not restricted to the current level of the transport theory. Furthermore, limits and options of this model are to be validated by means of four building materials on the basis of special transient moisture profile measurements. The study’s starting point is a comprehensive investigation of both, the different existing modelling approaches and the available experimental methods to determine basic hygrothermal material parameters. On this basis, the material modelling is set into the context of the heat and moisture transport theory derived from thermodynamics. The involved limits and restrictions are highlighted and options as well as requirements for further developments are pointed out. The developments this study focuses on comprise three fields: experiments for basic property determination, material modelling, and experiments for material model validation. The set of basic material investigation methods has been extended by the drying experiment under defined conditions. The different influences on the drying as well as its application to hygrothermal material model calibration are pointed out and appraised. On this basis, a drying apparatus is designed, built and applied. Ultimately, standardisation criteria and the derivation of a single-value drying coefficient are evaluated. Appropriate extensions are indicated. Based on the bundle of tubes approach, an own material model is developed. It is coupled with a mechanistical approach accounting for serial and parallel structured moisture transport phenomena. The derived liquid water conductivity is adjusted by the help of measured conductivity data close to saturation as well as within the hygroscopic moisture range. Subsequently, two internal modelling parameters are calibrated which is done by numerical simulation of the water uptake and the drying experiment under consideration of the hysteresis of moisture storage. Facilitating its application to the obtained laboratory data, the material model has been implemented into a computer program. It is applied to the four building materials brick, lime-sand brick, aerated concrete and calcium silicate. The adjusted material functions are shown and discussed. In all four cases, the calibration provides an excellent agreement between measured and calculated material behaviour. As experimental basis of the material model validation, the instantaneous profile measurement technique (IPM) has been extended to be applied in Building Physics. Special equipment is developed and measurement procedures are designed. Different models to derive the water content from dielectric data obtained by Time Domain Reflectometry (TDR) measurements are evaluated and implemented. Ultimately, an extensive program of transient moisture profile measurements within the hygroscopic and the overhygroscopic moisture content range is conducted and evaluated. Within the frame of validation, the developments on the experimental as well as on the modelling fields are combined. The IPM experiments are recalculated on the basis of the measured initial and boundary conditions applying the adjusted and calibrated material functions. The comparison of measured and calculated data reveals the power of the developed material modelling just as the consequences of the simplifications made on the transport theory level. The distinct influences of the hysteresis of moisture storage consisting of effects depending on the process history and effects depending on the process dynamics, are proven. By the presented study, the material modelling has been decisively further developed, the set of basic measurement methods has been extended by a substantial experiment and the instantaneous profile measurement technique has been made applicable to Building Physics. Moreover, the influences of the process history and the process dynamics on the moisture transport and the resulting moisture profiles could be shown and proven. By that, not only a material model is now available which perfectly applies to the requirements of flexibility, applicability and extendability. The obtained data provides also a powerful basis for further research and development. / Die Genauigkeit hygrothermischer Bauteilsimulation hängt maßgeblich von den verwendeten Materialfunktionen ab. Sie werden durch die Materialmodellierung bestimmt, welche die Verbindung zwischen den aus Basisexperimenten gewonnenen Speicher- und Transportparametern sowie den innerhalb der Bilanz- und Flussgleichungen definierten Speicher- und Transportkoeffizienten herstellt. Ziel der vorliegenden Arbeit ist zum einen die Entwicklung eines flexiblen, breit anwendbaren und gleichzeitig nicht auf den gegenwärtigen Stand der Transporttheorie beschränkten Materialmodells. Dessen Grenzen und Möglichkeiten sollen zum anderen auf der Grundlage spezieller instationärer Feuchteprofilmessungen anhand von vier Baustoffen untersucht und aufgezeigt werden. Ausgangspunkt der Arbeit ist eine ausführliche Beleuchtung sowohl der vorhandenen Modellansätze als auch der zur Verfügung stehenden experimentellen Methoden zur Bestimmung hygrothermischer Basisparameter. Auf dieser Grundlage wird die Materialmodellierung in den Kontext der aus der Thermodynamik abgeleiteten Wärmeund Feuchtetransporttheorie eingeordnet. Die damit verbundenen Grenzen und Einschränkungen werden hervorgehoben und Entwicklungsmöglichkeiten sowie weiterer Entwicklungsbedarf aufgezeigt. Dieser umfasst drei Bereiche: die Experimente zur Bestimmung von Basisparametern, die Materialmodellierung, sowie Experimente zur Modellvalidierung. Die Reihe der Basisexperimente wird um den Trocknungsversuch unter definierten Bedingungen erweitert. Die verschiedenen Einflüsse auf die Trocknung und deren Anwendung in der Kalibrierung hygrothermischer Materialmodellierung werden herausgestellt und bewertet. Darauf aufbauend wird eine Apparatur entworfen, gebaut und angewendet. Schließlich werden Kriterien zur Standardisierung und Ableitung eines Einzahlenkennwertes evaluiert. Sinnvolle Erweiterungen werden aufgezeigt. Es wird ein eigenes Materialmodell auf der Grundlage eines Porenbündelansatzes hergeleitet, welches mit einem mechanistischen Ansatz gekoppelt wird, der den Feuchtetransport in seriell und parallel strukturierte Bereiche untergliedert. Die abgeleitete Flüssigwasserleitfähigkeit wird anhand von Leitfähigkeitsmessdaten im nahe gesättigten sowie im hygroskopischen Feuchtebereich justiert. Zwei interne Modellparameter werden anschließend unter Berücksichtigung der Hysterese der Feuchtespeicherung anhand des Aufsaug- und des Trocknungsversuches kalibriert. Das Materialmodell ist zur Erleichterung der Anwendung in ein Computerprogramm zur Anpassung an die Labordaten implementiert worden. Das Programm wird auf die vier Baustoffe Ziegel, Kalksandstein, Porenbeton und Calciumsilikat angewendet. Die entsprechend angepassten Materialfunktionen werden gezeigt und diskutiert. Im Rahmen der Kalibrierung wird eine hervorragende Übereinstimmung zwischen gemessenem und berechnetem Materialverhalten erreicht. Zur Modellvalidierung wird die Augenblicksprofilmethode (IPM) für die bauphysikalische Anwendung erweitert. Spezielle Apparaturen werden entwickelt und Versuchsabläufe entworfen. Modelle zur Ableitung des Wassergehaltes aus mit Hilfe der Time Domain Reflectometry (TDR) gewonnenen Dielektrizitätsmessdaten werden evaluiert und implementiert. Schließlich wird ein umfangreiches Programm an Feuchteprofilmessungen im hygroskopischen und überhygroskopischen Feuchtebereich umgesetzt und ausgewertet. Im Rahmen der Validierung werden die Entwicklungen auf experimenteller sowie auf Modellierungsebene zusammengeführt. Die IPM Experimente werden anhand der gemessenen Anfangs- und Randbedingungen und auf der Grundlage der angepassten und kalibrierten Materialfunktionen nachgerechnet. Der Vergleich zwischen Messung und Rechnung offenbart die Stärke der entwickelten Materialmodellierung ebenso, wie den Einfluss der auf Ebene der Transporttheorie getroffenen Vereinfachungen. Ein deutlicher Einfluss der sich aus der Prozessgeschichte sowie der Prozessdynamik zusammensetzenden Hysterese der Feuchtespeicherung kann nachgewiesen werden. Mit der vorliegenden Arbeit ist somit nicht nur die Materialmodellierung entscheidend weiterentwickelt, die Reihe der einfachen Basisexperimente um einen wesentlichen Versuch erweitert und die Augenblicksprofilmethode für bauphysikalische Belange anwendbar gemacht worden, es wurden auch die Einflüsse der Prozessgeschichte, und erstmals auch der Prozessdynamik, auf den Feuchtetransport sowie die sich einstellenden Feuchteprofile deutlich aufgezeigt und nachgewiesen. Es ist demnach nicht nur ein Materialmodell, welches den gestellten Anforderungen an Flexibilität, breite Anwendbarkeit und Erweiterbarkeit genügt, entwickelt worden, es wird mit den gewonnenen Messdaten auch die Grundlage weiterer Forschung zur Verfügung gestellt.
10

Validation of hygrothermal material modelling under consideration of the hysteresis of moisture storage

Scheffler, Gregor 12 February 2008 (has links)
The achievable accuracy of hygrothermal building component simulation is significantly dependent on the applied material functions. These functions are determined by the material modelling marking the connection between the basic storage and transport parameters which are obtained from basic measurements, and the storage and transport coefficients which are defined within the balance and flow equations. It is the aim of the present study to develop a flexible and widely applicable material model which is not restricted to the current level of the transport theory. Furthermore, limits and options of this model are to be validated by means of four building materials on the basis of special transient moisture profile measurements. The study’s starting point is a comprehensive investigation of both, the different existing modelling approaches and the available experimental methods to determine basic hygrothermal material parameters. On this basis, the material modelling is set into the context of the heat and moisture transport theory derived from thermodynamics. The involved limits and restrictions are highlighted and options as well as requirements for further developments are pointed out. The developments this study focuses on comprise three fields: experiments for basic property determination, material modelling, and experiments for material model validation. The set of basic material investigation methods has been extended by the drying experiment under defined conditions. The different influences on the drying as well as its application to hygrothermal material model calibration are pointed out and appraised. On this basis, a drying apparatus is designed, built and applied. Ultimately, standardisation criteria and the derivation of a single-value drying coefficient are evaluated. Appropriate extensions are indicated. Based on the bundle of tubes approach, an own material model is developed. It is coupled with a mechanistical approach accounting for serial and parallel structured moisture transport phenomena. The derived liquid water conductivity is adjusted by the help of measured conductivity data close to saturation as well as within the hygroscopic moisture range. Subsequently, two internal modelling parameters are calibrated which is done by numerical simulation of the water uptake and the drying experiment under consideration of the hysteresis of moisture storage. Facilitating its application to the obtained laboratory data, the material model has been implemented into a computer program. It is applied to the four building materials brick, lime-sand brick, aerated concrete and calcium silicate. The adjusted material functions are shown and discussed. In all four cases, the calibration provides an excellent agreement between measured and calculated material behaviour. As experimental basis of the material model validation, the instantaneous profile measurement technique (IPM) has been extended to be applied in Building Physics. Special equipment is developed and measurement procedures are designed. Different models to derive the water content from dielectric data obtained by Time Domain Reflectometry (TDR) measurements are evaluated and implemented. Ultimately, an extensive program of transient moisture profile measurements within the hygroscopic and the overhygroscopic moisture content range is conducted and evaluated. Within the frame of validation, the developments on the experimental as well as on the modelling fields are combined. The IPM experiments are recalculated on the basis of the measured initial and boundary conditions applying the adjusted and calibrated material functions. The comparison of measured and calculated data reveals the power of the developed material modelling just as the consequences of the simplifications made on the transport theory level. The distinct influences of the hysteresis of moisture storage consisting of effects depending on the process history and effects depending on the process dynamics, are proven. By the presented study, the material modelling has been decisively further developed, the set of basic measurement methods has been extended by a substantial experiment and the instantaneous profile measurement technique has been made applicable to Building Physics. Moreover, the influences of the process history and the process dynamics on the moisture transport and the resulting moisture profiles could be shown and proven. By that, not only a material model is now available which perfectly applies to the requirements of flexibility, applicability and extendability. The obtained data provides also a powerful basis for further research and development. / Die Genauigkeit hygrothermischer Bauteilsimulation hängt maßgeblich von den verwendeten Materialfunktionen ab. Sie werden durch die Materialmodellierung bestimmt, welche die Verbindung zwischen den aus Basisexperimenten gewonnenen Speicher- und Transportparametern sowie den innerhalb der Bilanz- und Flussgleichungen definierten Speicher- und Transportkoeffizienten herstellt. Ziel der vorliegenden Arbeit ist zum einen die Entwicklung eines flexiblen, breit anwendbaren und gleichzeitig nicht auf den gegenwärtigen Stand der Transporttheorie beschränkten Materialmodells. Dessen Grenzen und Möglichkeiten sollen zum anderen auf der Grundlage spezieller instationärer Feuchteprofilmessungen anhand von vier Baustoffen untersucht und aufgezeigt werden. Ausgangspunkt der Arbeit ist eine ausführliche Beleuchtung sowohl der vorhandenen Modellansätze als auch der zur Verfügung stehenden experimentellen Methoden zur Bestimmung hygrothermischer Basisparameter. Auf dieser Grundlage wird die Materialmodellierung in den Kontext der aus der Thermodynamik abgeleiteten Wärmeund Feuchtetransporttheorie eingeordnet. Die damit verbundenen Grenzen und Einschränkungen werden hervorgehoben und Entwicklungsmöglichkeiten sowie weiterer Entwicklungsbedarf aufgezeigt. Dieser umfasst drei Bereiche: die Experimente zur Bestimmung von Basisparametern, die Materialmodellierung, sowie Experimente zur Modellvalidierung. Die Reihe der Basisexperimente wird um den Trocknungsversuch unter definierten Bedingungen erweitert. Die verschiedenen Einflüsse auf die Trocknung und deren Anwendung in der Kalibrierung hygrothermischer Materialmodellierung werden herausgestellt und bewertet. Darauf aufbauend wird eine Apparatur entworfen, gebaut und angewendet. Schließlich werden Kriterien zur Standardisierung und Ableitung eines Einzahlenkennwertes evaluiert. Sinnvolle Erweiterungen werden aufgezeigt. Es wird ein eigenes Materialmodell auf der Grundlage eines Porenbündelansatzes hergeleitet, welches mit einem mechanistischen Ansatz gekoppelt wird, der den Feuchtetransport in seriell und parallel strukturierte Bereiche untergliedert. Die abgeleitete Flüssigwasserleitfähigkeit wird anhand von Leitfähigkeitsmessdaten im nahe gesättigten sowie im hygroskopischen Feuchtebereich justiert. Zwei interne Modellparameter werden anschließend unter Berücksichtigung der Hysterese der Feuchtespeicherung anhand des Aufsaug- und des Trocknungsversuches kalibriert. Das Materialmodell ist zur Erleichterung der Anwendung in ein Computerprogramm zur Anpassung an die Labordaten implementiert worden. Das Programm wird auf die vier Baustoffe Ziegel, Kalksandstein, Porenbeton und Calciumsilikat angewendet. Die entsprechend angepassten Materialfunktionen werden gezeigt und diskutiert. Im Rahmen der Kalibrierung wird eine hervorragende Übereinstimmung zwischen gemessenem und berechnetem Materialverhalten erreicht. Zur Modellvalidierung wird die Augenblicksprofilmethode (IPM) für die bauphysikalische Anwendung erweitert. Spezielle Apparaturen werden entwickelt und Versuchsabläufe entworfen. Modelle zur Ableitung des Wassergehaltes aus mit Hilfe der Time Domain Reflectometry (TDR) gewonnenen Dielektrizitätsmessdaten werden evaluiert und implementiert. Schließlich wird ein umfangreiches Programm an Feuchteprofilmessungen im hygroskopischen und überhygroskopischen Feuchtebereich umgesetzt und ausgewertet. Im Rahmen der Validierung werden die Entwicklungen auf experimenteller sowie auf Modellierungsebene zusammengeführt. Die IPM Experimente werden anhand der gemessenen Anfangs- und Randbedingungen und auf der Grundlage der angepassten und kalibrierten Materialfunktionen nachgerechnet. Der Vergleich zwischen Messung und Rechnung offenbart die Stärke der entwickelten Materialmodellierung ebenso, wie den Einfluss der auf Ebene der Transporttheorie getroffenen Vereinfachungen. Ein deutlicher Einfluss der sich aus der Prozessgeschichte sowie der Prozessdynamik zusammensetzenden Hysterese der Feuchtespeicherung kann nachgewiesen werden. Mit der vorliegenden Arbeit ist somit nicht nur die Materialmodellierung entscheidend weiterentwickelt, die Reihe der einfachen Basisexperimente um einen wesentlichen Versuch erweitert und die Augenblicksprofilmethode für bauphysikalische Belange anwendbar gemacht worden, es wurden auch die Einflüsse der Prozessgeschichte, und erstmals auch der Prozessdynamik, auf den Feuchtetransport sowie die sich einstellenden Feuchteprofile deutlich aufgezeigt und nachgewiesen. Es ist demnach nicht nur ein Materialmodell, welches den gestellten Anforderungen an Flexibilität, breite Anwendbarkeit und Erweiterbarkeit genügt, entwickelt worden, es wird mit den gewonnenen Messdaten auch die Grundlage weiterer Forschung zur Verfügung gestellt.

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