Orientador: Antonio Ludovico Beraldo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-08T10:50:49Z (GMT). No. of bitstreams: 1 Jose_FlavioJanuario_M.pdf: 4963085 bytes, checksum: 7b25d4ec4eb8715ae3a3a7150fea863d (MD5) Previous issue date: 2006 / Resumo: A pesquisa sobre o tema ¿Chapa de Partículas Homogêneas de Bambu aglomeradas com Resina Poliuretana à Base de Óleo de Mamona¿ teve como finalidade a confecção e a avaliação de chapas de partículas homogêneas aglomeradas, utilizando-se de dois materiais alternativos considerando a sustentabilidade do processo produtivo. Foram utilizadas partículas de Bambusa vulgaris devido à rapidez de crescimento dessa espécie de bambu, e da possibilidade de ser cultivado em praticamente todo o território brasileiro. Como adesivo foi utilizada a resina poliuretana à base de óleo de mamona, por ser de origem parcialmente renovável e, ao contrário dos adesivos convencionais, ser considerada não tóxica. Para a caracterização do material estudado, foram produzidas, em escala de laboratório, chapas cujas partículas de bambu utilizadas na sua composição, apresentaram espessura inferior a 2,4 mm, e aglomeradas com 5%, 10% e 15% de resina em relação à massa de partículas de bambu. Corpos-de-prova foram submetidos a ensaios físicos (controle de espessura, densidade, absorção de água e inchamento) e mecânicos (arrancamento de parafuso da superfície e do topo, dureza Janka, compressão longitudinal, flexão estática e tração perpendicular, segundo as recomendações da NBR 14810 - Chapas de madeira aglomerada). Corpos-de-prova destinados ao ensaio de compressão longitudinal também foram avaliados por meio de ensaio não destrutivo (END) por ultra-som. Os resultados obtidos foram comparados estatisticamente, sendo que o teor de resina em relação à massa de partículas de bambu afetou as propriedades físicas e mecânicas das chapas. O teor de 10% de resina não diferiu estatisticamente do teor 15%, sendo ambos superiores ao teor 5%. Embora o END tenha sido sensível para detectar o efeito dos teores de resina na velocidade do pulso ultra-sônico (VPU) através dos corpos-de-prova, não foi possível correlacionar a VPU com a resistência à compressão longitudinal. Para a maioria das propriedades avaliadas houve diferença estatística entre as chapas com 10% de resina e chapas de aglomerado cru disponíveis comercialmente, sendo que as chapas de aglomerado cru demonstraram resultados superiores, com exceção ao ensaio de inchamento em 24 h / Abstract: The aim of this research ¿Homogeneous Particleboard of Bamboo Bonded whith Poliurethane Resin Castor Oil Based¿ was to manufacture and to evaluate particleboards made with two alternative materials, looking for the productive process sustainability. Particles from Bambusa vulgaris were employed due to the its fast production cycle and its availability in Brazilian country. Poliurethane resin castor oil based was employed as a binder because it is parcially produced by a renewable source and its low toxicity. For the material caracterization it was manufactured at laboratory scale boards from bamboo particles smaller than 2.4 mm combined with 5%, 10% e 15% of resin in relation to the bamboo particles mass. Specimens were submited to physical (thickness control, density, water absorption and swelling after 2 hrs and 24 hrs of imersion in water) and mechanical (nail withdraw on surface and top, Janka hardness, longitudinal compression strength, static bending and internal bond) evaluations according to the Brazilian Standard NBR 14810 ¿ Boards of agglomerate wood. Specimens evaluated in longitudinal compression were previously tested through a Non Destructive Evaluation (NDE) by ultrasonic method. The results were statistically compared and showed that resin content related to bamboo particles afected the physical and mechanical board properties. 10% resin content was not statiscally different of 15% resin content, both superior to 5% resin content. Nevertheless NDE has been sensible to detect resin content effect on ultrasonic pulse velocity (UPV) across the specimens it was not possible to correlate with longitudinal compression strength. In most of the properties evaluated there was a statistical difference between bamboo particles boards with 10% resin content and the commercial agglomerated boards, being the commercial agglomerated boards demonstrated superior results, with exception to the swelling after 24 hrs / Mestrado / Construções Rurais e Ambiencia / Mestre em Engenharia Agrícola

This work is an experimental study of applying an impedance-based health monitoring technique to complex structures. The work is presented in three parts. In the first part we consider effects of the following three factors on damage detection abilities: actuator excitation level, test wire length and ambient conditions (temperature, structural loading and vibration). It was concluded that increasing the applied voltage improves the signal to noise ratio and damage detection abilities. Test wire lengths under 30m do not affect damage detection abilities. The technique is able to distinguish and detect damage even with variations in temperature, structural loading and vibration. In the second part we apply our health monitoring technique to a complex truss structure and a massive steel steam header. We discovered that with multiplexing (acquiring a single signal from distributed actuators) the actuators on the truss structure we could detect damage but with less location information. Damage detection on the steel pipe ended in inconclusive results. The use of this technique on massive structures needs further investigation. Finally, we conducted a detailed experimental study of monitoring the integrity of composite-reinforced masonry structures. We developed a software package which enables even a casual user to determine if significant damage has occurred in these structures. The technique was successfully applied to detect damage (particularly due to delamination) in these composite-concrete structures. Most significantly, the technique was also able to detect damage well in advance of actual failure. This work relies mainly on frequency response plots and damage metric charts to present the data and to arrive at any conclusions. While frequency response plots give a qualitative approach to the analysis, damage metric charts attempt to quantify the data. / Master of Science

No description available.

L'ondulation pli est un défaut majeur qui peut apparaître dans certains matériaux composites tels que le CFRP. Des mesures de vitesse et atténuation ultrasonore permettent la détection, mais pas l'identification, de l'ondulation pli. Dans la présente étude, il est démontré que pour identifier cette ondulation pli, il est important de prendre en compte la déviation du faisceau ultrasonore. Deux méthodes différentes, A²Scan et C²Scan, permettent de détecter et mesurer cette déviation. D'une part, de l'écart produit un comportement asymétrique dans les réponses obtenues à des angles d'incidence oblique. Ce phénomène se manifeste à travers l'étude des domaines d'angles d'incidence, qui peuvent normalement être superposés. D'autre part, la technique de C²Scan permet la mesure de la déviation du champ acoustique transmis. Dans les deux cas, l'étude de la déviation induite révèle sa sensibilité à la présence d'ondulation plis. Ces méthodes ont été validées expérimentalement et leur utilisation potentielle, en fonction de l'épaisseur de la pièce, ainsi que sont industrialisation par ultrasons laser sont discutées. / Ply waviness is a major defect, which can appear in certain composite materials such as CFRP. Attenuation and ultrasound velocity measurements allow the detection, but not the identification, of ply waviness. In the present study it is shown that in order to identify this ply waviness, it is important to take the deviation of the ultrasonic beam into account. Two different methods,A²Scan et C²Scan , allowing such deviations to be detected are proposed. On the one hand, the deviation produces an asymmetrical behaviour in the responses obtained at oblique incidence angles. This phenomenon is revealed through the study of incidence angle ranges, which can normally be superimposed. On the other hand, the double scanning technique allows the deviation of the energy maxima of the transmitted acoustic field to be determined. In both cases, the study of induced deviation reveals that it is sensitive to the presence of ply waviness. These methods have been experimentally validated and their potential use, depending on the thickness of the workpiece and industrialization by laser ultrasonic means are discussed.

The electric Joule heating of solid materials through direct current excitation can be used to generate a temperature profile throughout a powdermetallic (P/M) compact. When recording the surface temperature distribution with an infrared (IR) camera important information regarding the integrity of the sample can be gained. This research will concentrate on the formulation of a mathematical model capable of predicting the temperature distribution and heat flow behavior in P/M parts and its relations to the supplied current, injection method, geometric shape as well as the thermo-physical properties. This theoretical model will subsequently be employed as a tool to aid in the actual measurements of infrared signatures over the sample surface and their correlation with the detection of surface and subsurface flaws. In this work we will develop the theoretical background of IR testing of green-state and sintered P/M compacts in terms of stating the governing equations and boundary conditions, followed by devising analytical and numerical solutions. Our main emphasis is placed on modeling various flaw sizes and orientations in an effort to determine flaw resolution limits as a function of minimally detectable temperature distributions. Preliminary measurements with controlled and industrial samples have shown that this IR testing methodology can successfully be employed to test both green-state and sintered P/M compacts.

Although the study of the interaction of acoustic and elastic waves with periodic surfaces and structures has a rich history dating back to Lord Rayleigh, it has recently been attracting new research efforts due to its value in the study of phononic crystals and in methods for ultrasonic non-destructive evaluation (NDE). The objective of the research described in this thesis is to provide new numerical and experimental tools capable of capturing important features that occur due to the diffraction of ultrasound on periodic solid surfaces. This thesis is divided into four main parts. First, the Rayleigh-Fourier (R-F) method will be used to simulate diffracted fields generated by structures containing multiple periodic surfaces and/or multiple solid layers. The second part of this thesis examines diffraction effects and compares ultrasonic NDE techniques for surfaces with imperfect periodicities. The third portion of this thesis focuses on one unusual phenomenon that has been observed on periodic surfaces, namely the lateral backward displacement of a bounded ultrasonic beam along the surface. This effect is currently understood to occur due to backward propagating surface waves that result from diffraction and mode conversion on the surface. The fourth and final part of this thesis describes the diffraction of bulk ultrasonic waves that can occur on the surfaces of phononic crystals.

La détection d'endommagements et de changements des propriétés élastiques dans des structures, utilisant les variations des paramètres dynamiques, fait l'objet d'une attention particulière depuis plusieurs années dans les domaines du génie mécanique et du génie civil. Le principe général repose sur le fait que la variation des propriétés physiques (e.g. rigidité, masse, module d'Young, conditions aux limites) entraîne une variation des caractéristiques dynamiques de la structure (e.g. fréquences de résonance, amortissements modaux et déformées modales). La présence d'endommagement provoque ainsi une diminution de la rigidité de la structure, c'est-à-dire une augmentation de sa flexibilité et de son amortissement que l'on retrouve dans la forme des modes et les valeurs des fréquences. Utilisant le changement de ces informations entre un état sain et un état endommagé, plusieurs méthodes non-destructives ont été proposées dans la littérature afin d'identifier et de localiser ces endommagements. Ces pratiques et ces activités sont d'une importance considérable puisqu'elles permettent en premier lieu d'anticiper et donc d'éviter des ruptures dans les structures, toujours catastrophiques, et plus généralement de mettre en place des plans de maintenance prédictives, en lien avec le suivi sur le long terme de leur intégrité (Structural Health Monitoring). Ces méthodes de surveillance se popularisent également du fait de la réduction des coûts des instrumentations, liés à l'apparition de nouveaux équipements à bas coût, ayant des performances satisfaisantes. L'objectif de ce travail est de tester les différentes solutions permettant la détection, la localisation et la quantification des changements dans des structures simples. Plusieurs méthodes ont été testées et une approche nouvelle a été proposée basée sur l'utilisation de la méthode des perturbations. Trois approches ont été suivies: une modélisation par éléments finis (analyse modale), une simulation numériques par éléments finis (analyse temporelle) et enfin des analyses expérimentales sur des poutres en Plexiglas au laboratoire, les trois volets de ce travail ayant permis de tester la sensibilité des méthodes non-destructives (NDE) globales et locales pour la détection et la localisation. Les changements ont été associés à une variation locale du module de Young (E), numériquement pour les solutions numériques et par chauffage local sur des sections de la poutre dans le volet expérimental. Dans tous les cas, nous sommes en situations réelles afin de proposer l'identification des caractéristiques modales par des méthodes opérationnelles (Operative Modal Analysis) telles que la méthode du décrément aléatoire et la méthode de décomposition dans le domaine fréquentiel (Frequency Domain Decomposition). Les résultats d'identification ont montré une très bonne corrélation entre les valeurs numériques et les valeurs expérimentales obtenues : fréquences de résonance et déformés modale. Pour identifier l'endommagement, les méthodes de localisation basées sur la courbure des déformées propres, la matrice de flexibilité, la courbure de flexibilité et enfin sur la méthode d'inversion des modes ont été employées. D'après les résultats obtenus, la méthode d'inversion se montre efficace dans le cas de variations modales faibles et transitoires, alors que la méthode de la courbure de flexibilité donne généralement de bons résultats et apparait robuste lorsque les variations sont plus prononcées.

Orientador: Antonio Ludovico Beraldo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-09T06:15:33Z (GMT). No. of bitstreams: 1 Espelho_JeanClaudioChiozzini_M.pdf: 5138907 bytes, checksum: 875754541cac182e91f3c878f2be3883 (MD5) Previous issue date: 2007 / Resumo: O bambu é uma matéria-prima com múltiplas aplicações, principalmente no setor da construção. Seu desenvolvimento e seu desempenho mecânico são obtidos após um curto intervalo de tempo, quando comparado com as árvores. O bambu é um material renovável e encontrado em abundância em regiões tropicais e subtropicais, nas quais é considerado um material de baixo custo. No entanto, a maior parte das espécies de bambu é altamente susceptível ao ataque de fungos e insetos. Basicamente, pode-se aumentar a durabilidade dos colmos de bambu de duas maneiras, representadas por procedimentos culturais (naturais) e pelo tratamento dos colmos com produtos químicos. Dentre os diversos métodos que visam aumentar a durabilidade do bambu destaca-se o ¿Método de Boucherie Modificado¿. Neste trabalho testou-se a eficiência da aplicação do Método de Boucherie Modificado, comparando o aumento na durabilidade das amostras tratadas (taliscas de bambu) com amostras não tratadas ou testemunhas. Para tal, foram avaliados os efeitos de algumas variáveis como: posição da amostra no colmo, tipos de preservativo e sua concentração, duração do tratamento e tempo de exposição das taliscas em dois ambientes (protegido e exposto). Foram realizados ensaios não destrutivos - END (visual, pesagem das amostras e de ultra-som) e destrutivo (flexão estática). Também foram efetuadas análises químicas (concentração dos elementos químicos nas soluções e seu teor nas regiões do colmo) e de rastreabilidade dos elementos químicos por microscopia eletrônica de varredura (MEV). Os resultados obtidos permitiram verificar a falta de uniformidade da distribuição dos elementos químicos ao longo dos constituintes anatômicos do bambu, ocorrendo a deposição dos mesmos basicamente nos vasos. Verificou-se, igualmente, a ineficiência do uso de soluções com baixa concentração, principalmente quando foram combinadas com tratamentos de curta duração. Os ensaios de ultra-som e de flexão estática foram suficientemente sensíveis para detectar a melhor combinação do efeito dos parâmetros avaliados / Abstract: Bamboo is a raw material with several possibilities of applications, mainly for building purposes. Its development and its mechanical performance are obtained after a short interval of growing when compared with trees. Bamboo is renewable raw material and it is available in tropical and subtropical regions, where it is considered as a cheap material. Nevertheless, the most of bamboo species is highly decayed by insects and fungi attacks. Basically the bamboo culm protection can be obtained by means of a two treatment types: natural protection and chemical protection. In this last category one of the most employed is the Boucherie Modified Method. In this work it was evaluated the performance of a Boucherie Modified Method, comparing treated bamboo samples (bamboo splits) with no treated samples (control). It was evaluated the effect of the sample position in the culm, chemical solution type and its concentration, treatment elongation and the exposition period in two environment (protected and no protected). Non destructive evaluation - NDE (visual, weight control and ultrasound) and flexure test were applied to the specimens along the time. Also chemical analysis (chemical element concentration in the solution and its amount in the bamboo regions) and the traceability of these chemical elements by means a scanning electronic microscope (SEM) were employed. Results obtained showed a lack of uniformity of the distribution of the chemical elements across the bamboo anatomical constituents, occurring the salt deposition mainly in the vessel with a greater diameter. Smaller concentration solutions, mainly when they were combined with smaller treatment time, were not effective to protect bamboo against decay. Results obtained by ultrasound and flexure test were sensitive enough to detect the best combination of the effect of the parameters evaluated. / Mestrado / Construções Rurais e Ambiencia / Mestre em Engenharia Engenharia Agrícola

Bei der Assemblierung von Lithium-Ionen-Batterien ist ein zentraler Arbeitsschritt die Herstellung der elektrischen Verbindung von einzelnen Lithium-Ionen-Zellen in Reihen- und/oder Parallelschaltung. Dazu kommen in der Regel Überlappschweißverbindungen aus Blechen mit Dicken von unter 2 mm zum Einsatz. Typischerweise werden Eisen-, Aluminium- und Kupferwerkstoffe genutzt. Dieser Produktionsschritt ist wegen der Wichtigkeit für die gesamte Batteriefunktion in seiner Qualität zu überwachen. Im Rahmen dieser Arbeit wird ein dafür geeignetes Verfahren identifiziert. Es wurden Ultraschallprüfverfahren, Durchstrahlungsverfahren, die Messung des elektrischen Widerstands sowie thermografische Verfahren auf ihre Eignung zur Prüfung derartiger Überlappschweißverbindungen hin untersucht. Dabei zeigte sich, dass die nach dem Stand der Technik verfügbaren Verfahren im betrachteten Anwendungsfall wegen unzureichender Zugänglichkeit, mangelnder Fähigkeit der Fehlerdetektion oder wirtschaftlicher Gründe häufig nur eingeschränkt einsetzbar sind. Demzufolge war ein neues Verfahren zur Prüfung der Schweißnähte zur elektrischen Verbindung von Zellen zu entwickeln. Als Ansatz wurde die optisch angeregte Thermografie gewählt. Diese konnte erfolgreich eingesetzt werden, wenn ein Laser zur Anregung sowie eine Photonendetektorkamera zur Detektion genutzt wurde. Durch die Anwendung der Lockin-Thermografie konnten Rauscheinflüsse auf die Messung minimiert werden. Es konnte gezeigt werden, dass Lockin-Messungen auch dann ausgewertet können, wenn das gemessene Temperatursignal neben einer harmonischen Schwingung und Rauschen einen stetigen Temperaturtrend aufweist. Die Anwendung von im Rahmen der Arbeit entwickelten Abschirmelementen, die für die Anregungsstrahlung transparent und die von der genutzten Kamera erfassten Strahlung undurchlässig sind, erlaubte die Prüfung metallischer Schweißverbindung in der Nähe von hochabsorptiven Flächen. Unter Nutzung eines neu entwickelten Auswertealgorithmus, der auf die Kompensation des Effekts lateraler Wärmeflüsse im untersuchten Bauteil zielt, konnte die Ergebnisqualität der Thermografie hinsichtlich einer besseren optischen Korrelation der Ergebnisbilder zu Referenzprüfungen sowie einer verringerten Messunsicherheit der angebundenen Fläche verbessert werden. Insgesamt zeigte sich das Verfahren in seiner weiterentwickelten Form als für die Prüfung tauglich.:1 Einleitung 1.1 Motivation und Ziel 1.2 Einführung in die Arbeit 2 Stand der Technik 2.1 Lithium-Ionen-Batterien für Elektrofahrzeuge 2.1.1 Lithium-Ionen-Batterien im Vergleich zu anderen Energiespeichern in der Elektromobilität 2.1.2 Aufbau und Funktion von Lithium-Ionen-Batterien 2.2 Fertigungstechnik der Kontaktierung von Lithium-Ionen-Zellen 2.2.1 Kontaktierung von Lithium-Ionen-Zellen 2.2.2 Schweißverfahren zur Kontaktierung von Lithium-Ionen-Zellen 2.3 Schweißnahtanforderungen und -fehler 2.4 Zerstörungsfreie Prüfung von Kontaktierverbindungen 2.4.1 Qualitätssicherung von Kontaktierverbindungen 2.4.2 Anforderungen an zerstörungsfreie Prüfverfahren 2.4.3 Ultraschallprüfung 2.4.4 Durchstrahlungsprüfung 2.4.5 Messung des elektrischen Widerstands 2.4.6 Oberflächenprüfung 2.4.7 Infrarotthermografie 3 Vorauswahl eines geeigneten Verfahrens der zerstörungsfreien Prüfung 3.1 Untersuchte Verfahren 3.2 Ultraschallverfahren 3.3 Durchstrahlungsverfahren 3.4 Messung des elektrischen Widerstands 3.5 Infrarotthermografie 3.6 Verfahrensauswahl 4 Anwendung der optisch angeregten Thermografie zur Schweißnahtprüfung 4.1 Herausforderungen bei der Messung von Kontaktierschweißverbindungen von Lithium-Ionen-Batterien 4.2 Narzisseffekt und Perspektivenkorrektur 4.3 Techniken der optischen Anregung 4.4 Signalaufbereitung durch Lockin-Verfahren 4.4.1 Lockin-Thermografie 4.4.2 Lockin-Thermografie im Nicht-Gleichgewichtszustand 5 Unterdrückung des Einflusses von Reflexionen bei der thermografischen Prüfung von Kontaktierverbindungen 5.1 Hintergrund 5.2 Lösungsansatz 5.3 Werkstoffauswahl 5.4 Erprobung 6 Kompensation des Einflusses lateraler Wärmeströme 6.1 Mehrdimensionaler Wärmefluss 6.2 Simulation des Einflusses lateraler Wärmeströme 6.2.1 Simulationsmodell 6.2.2 Simulationsresultate 6.3 Entwicklung eines Kompensationsalgorithmus 6.3.1 Ansatz 6.3.2 Ergebnis 6.3.3 Sensitivitätsanalyse 6.3.4 Fazit der simulativen Untersuchung des Kompensationsalgorithmus 6.4 Umsetzung und Verifikation des Kompensationsalgorithmus 6.4.1 Untersuchte Proben 6.4.2 Emissionsgradmessung 6.4.3 Ergebnisqualität 6.4.4 Grenzen des Algorithmus 7 Zusammenfassung 8 Ausblick / The electrical connection of a multitude of lithium-ion cells is of high importance for producing lithium-ion batteries. These connections are usually carried out with lap welds of steel, aluminium and copper sheets with a thickness of less than 2 mm. Due to its importance the electrical connection should be subject to non-destructive evaluation. Therefore, a suitable method was identified to evaluate the electrical connection. Technologies based on ultrasonic, radiographic and thermographic evaluation as well as measurement of electrical resistance have been studied regarding their potential to non-destructively test aforementioned lap welds. It was found that in the studied case state of the art technologies are limited by restraints regarding accessibility, cycle time and detectability of ctitical flaws. Therefore, a new technique for non-destructive testing of lap welds between cell connections, had to be be defined. Optically excited thermography was considered a promising approach. Optically excited thermography was applied successfully using a laser as excitation source and a photon detector camera to record infrared radiation. The application of the lock-in principle allowed significant noise reduction. It was shown that the evaluation of temperature sequences using the lock-in algorithm does not depend on a temperature signal that shows strict harmonic behaviour but could also be applied when the raw temperature sequence incorporated a trend. The application of newly developed radiation shields, which are transparent to the wavelengths of the excitation signal, but opaque to the wavelengths of infrared detection, allowed thermographic testing of metal surfaces in proximity to highly absorbing surfaces. A new algorithm was developed for evaluating thermographic sequences aimed at reducing the impact of lateral thermal flux. It was proven to increase the quality of thermographic results in terms of visual correlation to reference technologies and measurement uncertainty of the joined area. Overall, the improved technology was found to be feasible for non-destructive testing of lap welds in lithium-ion batteries.:1 Einleitung 1.1 Motivation und Ziel 1.2 Einführung in die Arbeit 2 Stand der Technik 2.1 Lithium-Ionen-Batterien für Elektrofahrzeuge 2.1.1 Lithium-Ionen-Batterien im Vergleich zu anderen Energiespeichern in der Elektromobilität 2.1.2 Aufbau und Funktion von Lithium-Ionen-Batterien 2.2 Fertigungstechnik der Kontaktierung von Lithium-Ionen-Zellen 2.2.1 Kontaktierung von Lithium-Ionen-Zellen 2.2.2 Schweißverfahren zur Kontaktierung von Lithium-Ionen-Zellen 2.3 Schweißnahtanforderungen und -fehler 2.4 Zerstörungsfreie Prüfung von Kontaktierverbindungen 2.4.1 Qualitätssicherung von Kontaktierverbindungen 2.4.2 Anforderungen an zerstörungsfreie Prüfverfahren 2.4.3 Ultraschallprüfung 2.4.4 Durchstrahlungsprüfung 2.4.5 Messung des elektrischen Widerstands 2.4.6 Oberflächenprüfung 2.4.7 Infrarotthermografie 3 Vorauswahl eines geeigneten Verfahrens der zerstörungsfreien Prüfung 3.1 Untersuchte Verfahren 3.2 Ultraschallverfahren 3.3 Durchstrahlungsverfahren 3.4 Messung des elektrischen Widerstands 3.5 Infrarotthermografie 3.6 Verfahrensauswahl 4 Anwendung der optisch angeregten Thermografie zur Schweißnahtprüfung 4.1 Herausforderungen bei der Messung von Kontaktierschweißverbindungen von Lithium-Ionen-Batterien 4.2 Narzisseffekt und Perspektivenkorrektur 4.3 Techniken der optischen Anregung 4.4 Signalaufbereitung durch Lockin-Verfahren 4.4.1 Lockin-Thermografie 4.4.2 Lockin-Thermografie im Nicht-Gleichgewichtszustand 5 Unterdrückung des Einflusses von Reflexionen bei der thermografischen Prüfung von Kontaktierverbindungen 5.1 Hintergrund 5.2 Lösungsansatz 5.3 Werkstoffauswahl 5.4 Erprobung 6 Kompensation des Einflusses lateraler Wärmeströme 6.1 Mehrdimensionaler Wärmefluss 6.2 Simulation des Einflusses lateraler Wärmeströme 6.2.1 Simulationsmodell 6.2.2 Simulationsresultate 6.3 Entwicklung eines Kompensationsalgorithmus 6.3.1 Ansatz 6.3.2 Ergebnis 6.3.3 Sensitivitätsanalyse 6.3.4 Fazit der simulativen Untersuchung des Kompensationsalgorithmus 6.4 Umsetzung und Verifikation des Kompensationsalgorithmus 6.4.1 Untersuchte Proben 6.4.2 Emissionsgradmessung 6.4.3 Ergebnisqualität 6.4.4 Grenzen des Algorithmus 7 Zusammenfassung 8 Ausblick

No description available.