Background: Mechanical ventilation (MV) inflicts stress on the lungs, initiating or increasing lung inflammation, so-called ventilator-induced lung injury (VILI). Besides overdistention, cyclic opening-and-closing of alveoli (atelectrauma) is recognized as a potential mechanism of VILI. The dynamic stretch may be reduced by positive endexpiratory pressure (PEEP), which in turn increases the static stretch. We investigated whether static stretch modulates the inflammatory response of rat type 2 alveolar epithelial cells (AECs) at different levels of dynamic stretch and hypothesized that static stretch increases pro-inflammatory response of AECs at given dynamic stretch. - Methods: AECs, stimulated and not stimulated with lipopolysaccharide (LPS), were subjected to combinations of static (10, 20, and 30%) and dynamic stretch (15, 20, and 30%), for 1 and 4 h. Non-stretched AECs served as control. The gene expression and secreted protein levels of interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein 2 (MIP-2) were studied by real-time polymerase chain reaction (RTqPCR) and enzyme-linked immunosorbent assay (ELISA), respectively. The effects of static and dynamic stretch were assessed by two-factorial ANOVA with planned effects post-hoc comparison according to Šidák. Statistical significance was considered for p < 0.05. - Results: In LPS-stimulated, but not in non-stimulated rat type 2 AECs, compared to nonstretched cells: 1) dynamic stretch increased the expression of amphiregulin (AREG) (p < 0.05), MCP-1 (p < 0.001), and MIP-2 (<0.05), respectively, as well as the protein secretion of IL-6 (p < 0.001) and MCP-1 (p < 0.05); 2) static stretch increased the gene expression of MCP-1 (p < 0.001) and MIP-2, but not AREG, and resulted in higher secretion of IL-6 (p < 0.001), but not MCP-1, while MIP-2 was not detectable in the medium. - Conclusion: In rat type 2 AECs stimulated with LPS, static stretch increased the proinflammatory response to dynamic stretch, suggesting a potential pro-inflammatory effect of PEEP during mechanical ventilation at the cellular level.

This work describes static and dynamic problems with one messenger or multiple number of messengers and suggests a possibility of solving such problems with modified heuristic methods. To solve messenger problem, modified nearest neighbor heuristic, modified insertion heuristic and modified exchange heuristic are used. The main contribution of this work are applications, developed in MS Excel, programmed with Visual Basic for Application, that can solve static and dynamic problems with one messenger or multiple number of messengers and that could be beneficial for companies that do business in messenger services.

<p>Циљ рада: Циљ истраживања је да се утврди разлика у акутним ефектима статичког (СИ) и динамичког истезања (ДИ), у комбинацији са специфичним кошаркашким загревањем (СКЗ), на флексибилност, експлозивну снагу ногу, брзину, агилност и неуромишићну адаптацију кошаркаша јуниорског узраста.</p><p>Методе: Истраживање у оквиру ове докторске тезе су чинила два одвојена експеримента, један спроведен у теренским условима, и други спроведен у лабораторијским. Оба су била &bdquo;cross-over&ldquo; дизајна. У теренском експерименту је учествовало 46 кошаркаша (узраста 17&plusmn;0,83 година), док је у лабораторијском учествовало 12 (узраста 17,7&plusmn;0,49 година). У теренском експерименту су тестиране четири моторичке способности. За процену флексибилности коришћен је тест досезања у седећем претклону, експлозивна снага ногу је процењивана уз помоћ вертикалног скока са контактне плоче, брзина трчањем на 20 метара, док је Т тест коришћен за процену агилности. У лабораторијском експерименту је као мера неурофизиолошке адаптације коришћена промена ексцитабилности &alpha;-мотонеурона, која је представљена као однос Хофмановог (Х) рефлекса и М таласа (Х/М). За њихово одређивање се користио Medelec ST-10 стимулатор (Medelec, Old Woking, UK). Површинске електромиографске електроде су биле постављене на унутрашњој глави m.gastrocnemius-a одскочне ноге, применом тзв. &bdquo;belly-tendon&ldquo; монтаже. Као третмани, у оба експеримента су коришћени протокол статичког и протокол динамичког истезања, уз комбинацију са специфичним кошаркашким загревањем. Мерења су се у оба експеримента изводила у 3 временске тачке и то пре протокола истезања, одмах након протокола истезања (а пре специфичног кошаркашког загревања) и одмах након специфичног кошаркашког загревања.</p><p>Резултати: Резултати истраживања показују да постоје одређене разлике акутних ефеката комбинација протокола СИ+СКЗ и ДИ+СКЗ. Комбинација протокола СИ+СКЗ је повољније утицала на експлозивну снагу ногу и на агилност кошаркаша јуниорског узраста. Ефекти обе комбинације протокола су били готово идентични на флексибилност, а разлика је изостала и у ефектима на брзину, иако је пре СКЗ био&nbsp;уочљив негативан ефекат СИ. Однос Х/М се значајно разликовао одмах након истезања, када је СИ значајно оборило однос, али су се те разлике изгубиле након примене СКЗ.</p><p>Закључак: Посматрајући ефекте комбинације протокола СИ+СКЗ и ДИ+СКЗ на моторичке способности и неуромишићну адаптацију кошаркаша јуниорског узраста, може се закључити да је примена СИ+СКЗ препоручљивија у свакодневном тренингу и такмичењу.</p> / <p>Cilj rada: Cilj istraživanja je da se utvrdi razlika u akutnim efektima statičkog (SI) i dinamičkog istezanja (DI), u kombinaciji sa specifičnim košarkaškim zagrevanjem (SKZ), na fleksibilnost, eksplozivnu snagu nogu, brzinu, agilnost i neuromišićnu adaptaciju košarkaša juniorskog uzrasta.</p><p>Metode: Istraživanje u okviru ove doktorske teze su činila dva odvojena eksperimenta, jedan sproveden u terenskim uslovima, i drugi sproveden u laboratorijskim. Oba su bila &bdquo;cross-over&ldquo; dizajna. U terenskom eksperimentu je učestvovalo 46 košarkaša (uzrasta 17&plusmn;0,83 godina), dok je u laboratorijskom učestvovalo 12 (uzrasta 17,7&plusmn;0,49 godina). U terenskom eksperimentu su testirane četiri motoričke sposobnosti. Za procenu fleksibilnosti korišćen je test dosezanja u sedećem pretklonu, eksplozivna snaga nogu je procenjivana uz pomoć vertikalnog skoka sa kontaktne ploče, brzina trčanjem na 20 metara, dok je T test korišćen za procenu agilnosti. U laboratorijskom eksperimentu je kao mera neurofiziološke adaptacije korišćena promena ekscitabilnosti &alpha;-motoneurona, koja je predstavljena kao odnos Hofmanovog (H) refleksa i M talasa (H/M). Za njihovo određivanje se koristio Medelec ST-10 stimulator (Medelec, Old Woking, UK). Površinske elektromiografske elektrode su bile postavljene na unutrašnjoj glavi m.gastrocnemius-a odskočne noge, primenom tzv. &bdquo;belly-tendon&ldquo; montaže. Kao tretmani, u oba eksperimenta su korišćeni protokol statičkog i protokol dinamičkog istezanja, uz kombinaciju sa specifičnim košarkaškim zagrevanjem. Merenja su se u oba eksperimenta izvodila u 3 vremenske tačke i to pre protokola istezanja, odmah nakon protokola istezanja (a pre specifičnog košarkaškog zagrevanja) i odmah nakon specifičnog košarkaškog zagrevanja.</p><p>Rezultati: Rezultati istraživanja pokazuju da postoje određene razlike akutnih efekata kombinacija protokola SI+SKZ i DI+SKZ. Kombinacija protokola SI+SKZ je povoljnije uticala na eksplozivnu snagu nogu i na agilnost košarkaša juniorskog uzrasta. Efekti obe kombinacije protokola su bili gotovo identični na fleksibilnost, a razlika je izostala i u efektima na brzinu, iako je pre SKZ bio&nbsp;uočljiv negativan efekat SI. Odnos H/M se značajno razlikovao odmah nakon istezanja, kada je SI značajno oborilo odnos, ali su se te razlike izgubile nakon primene SKZ.</p><p>Zaključak: Posmatrajući efekte kombinacije protokola SI+SKZ i DI+SKZ na motoričke sposobnosti i neuromišićnu adaptaciju košarkaša juniorskog uzrasta, može se zaključiti da je primena SI+SKZ preporučljivija u svakodnevnom treningu i takmičenju.</p> / <p>Objective: The aim of this study was to determine the difference of acute effects of static stretching (SS) and dynamic stretching (DS), in combination with specific basketball warm-up (SBWU), on flexibility, explosive leg strength, speed, agility and neuromuscular adaptation of basketball players U18.</p><p>Methods: This study consisted of two separated experiments, first in field conditions, and second conducted in laboratory. Both had &bdquo;cross-over&ldquo; design. Forty-six basketball players (age: 17&plusmn;0,83 years) participated in field experiment, while twelve participated in laboratory experiment (age 17,7&plusmn;0,49 years). In field experiment, four motor abilities were tested. Seat and rech test was used for the evaluation of flexibility, explosive leg strength was evaluated by vertical jump from contact plate, speed by 20m run, and T test was used for agility testing. In laboratory experiment, the excitability of &alpha;-motoneuron was taken for the evaluation of neuromuscular adaptation. It is presented as a ratio of the maximal amplitudes of Hoffman (H) reflex and M wave (H/M). For their determining we used Medelec ST-10 stimulator (Medelec, Old Woking, UK). Surface electromyographic (EMG) electrodes were placed over the m.gastrocnemius medialis, and Achilles tendon, in a &bdquo;belly-tendon&ldquo; montage. In both experiments, SS protocol and DS protocol, in the combination with SBWU, were used as a treatment. Measures were taken in 3 time points: before the stretching, immediately after stretching (and before SBWU) and immediately after the SBWU.</p><p>Results: Results of this study showed that there are certain differences in acute effects of combination of protocols SS+SBWU and DS+SBWU. Combination of protocols SS+SBWU had more positive influence on explosive leg strength and agility of U18 basketball players. The effects of both protocols were almost the same on flexibility, and there was no noticeable difference in effects on speed, although before SBWU there was significant negative of SS. Immediately after the stretching there was significant difference in H/M ratio, it was significantly lower after the SS, but after the application of SBWU, differences disappeared.<br />&nbsp;<br />Conlcusion: Regarding the effects of SS+SBWU and DS+SBWU protocols on motor abilities and neuromuscular adaptation of U18 basketball players, it could be concluded that the use of SS+SBWU is more preferrable in everyday practice and competition.</p>

This thesis provides a general methodology for classifying and describing many combinatoric problems, systematising and finding theoretical expressions for quantities of interest, and investigating their feasible numerical evaluation. Unifying notation and definitions are provided. Our knowledge of random allocations is also extended. This is achieved by investigating new processes, generalising known processes, and by providing a formal structure and innovative techniques for analysing them. The random allocation models described in this thesis can be classified as occupancy urn models, in which we have a sequence of urns and throw balls into them, and investigate static, waiting-time and dynamic processes. Various structures are placed on the relationship(s) between cells, balls, and the selection of items being distributed, including varieties, batch arrivals, taboo sets and blocking sets. Static, waiting-time and dynamic processes are investigated. Both without-replacement and with-replacement sampling types are considered. Emphasis is placed on the distributions of waiting-times for one or more events to occur measured from the time a particular event occurs; this begins as an abstraction and generalisation of a model of departures of cars parked in lanes. One of several additional determinations is the platoon size distribution. Models are analysed using combinatorial analysis and Markov Chains. Global attributes are measured, including maximum waits, maximum room required, moments and the clustering of completions. Various conversion formulae have been devised to reduce calculation times by several orders of magnitude. New and extended applications include Queueing in Lanes, Cake Displays, Coupon Collector's Problem, Sock-Sorting, Matching Dependent Sets (including Genetic Code Attribute Matching and the game SET), the Zig-Zag Problem, Testing for Randomness (including the Cake Display Test, which is a without-replacement test similar to the standard Empty Cell test), Waiting for Luggage at an Airport, Breakdowns in a Network, Learning Theory and Estimating the Number of Skeletons at an Archaeological Dig. Fundamental, reduction and covering theorems provide ways to reduce the number of calculations required. New combinatorial identities are discovered and a well-known one is proved in a combinatorial way for the first time. Some known results are derived from simple cases of the general models. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1309598 / Thesis (Ph.D.) -- University of Adelaide, School of Mathematical Sciences, 2007

Organizzata in tre saggi, questa tesi si pone l’obiettivo di consentire una migliore comprensione del legame tra crescita e istituzioni, e dei meccanismi attraverso cui gli assetti istituzionali possono condizionare i sentieri economici. Riconoscendo, sulla base di considerazioni storiche, il potere esemplificativo delle ex Repubbliche Socialiste Sovietiche e della loro comune esperienza passata, questo lavoro fornisce, da un lato, una struttura empirica di riferimento per esaminare l’impatto sulla performance economica di un insieme di istituzioni, concretamente legate al funzionamento dell’attività economica; dall’altro, approfondisce lo studio degli effetti e delle determinanti delle azioni di policy. Il primo saggio offre una disamina della letteratura riguardante il legame crescita e istituzioni, fornendo un quadro esaustivo degli sviluppi teorici ed empirici, e illustra diversi aspetti che possono essere concepiti come obiettivi per la ricerca futura; il secondo, attraverso la costruzione di un modello statico e di un modello dinamico, quantifica l’impatto delle istituzioni economiche sui sentieri di crescita di questi paesi, impiegando e analizzando numerose tecniche di stima; il terzo saggio formula diverse specificazioni e affronta il tema rilevante del ruolo degli interventi di policy sullo sviluppo economico e dell’effetto delle istituzioni politiche su comportamenti e decisioni del governo. / Organized in three essays, this thesis aims at achieving a better understanding of the link between growth and institutions, and of the mechanisms through which the institutional arrangements affect the economic paths. Exploiting the past common experience of the Former Soviet Union economies, this work provides an empirical framework to examine the impact on the economic performance of a set of institutions concretely related to the “functioning” of the economic activity and offers a first attempt to include in this research program the study of the consequences of the government actions. The first essay offers a thorough review of the literature researching on the link between economic growth and institutions, and elucidates several issues that deserve further attention; the second develops a static and a dynamic approach to assess, using multiple estimation techniques, the impact of a set of economic institutions on the growth paths of these countries; the third essay, through several formal specifications, deals with the relevant issue of the role of policy measures and of the effect of the political institutions on the governments behaviour.

This thesis provides a general methodology for classifying and describing many combinatoric problems, systematising and finding theoretical expressions for quantities of interest, and investigating their feasible numerical evaluation. Unifying notation and definitions are provided. Our knowledge of random allocations is also extended. This is achieved by investigating new processes, generalising known processes, and by providing a formal structure and innovative techniques for analysing them. The random allocation models described in this thesis can be classified as occupancy urn models, in which we have a sequence of urns and throw balls into them, and investigate static, waiting-time and dynamic processes. Various structures are placed on the relationship(s) between cells, balls, and the selection of items being distributed, including varieties, batch arrivals, taboo sets and blocking sets. Static, waiting-time and dynamic processes are investigated. Both without-replacement and with-replacement sampling types are considered. Emphasis is placed on the distributions of waiting-times for one or more events to occur measured from the time a particular event occurs; this begins as an abstraction and generalisation of a model of departures of cars parked in lanes. One of several additional determinations is the platoon size distribution. Models are analysed using combinatorial analysis and Markov Chains. Global attributes are measured, including maximum waits, maximum room required, moments and the clustering of completions. Various conversion formulae have been devised to reduce calculation times by several orders of magnitude. New and extended applications include Queueing in Lanes, Cake Displays, Coupon Collector's Problem, Sock-Sorting, Matching Dependent Sets (including Genetic Code Attribute Matching and the game SET), the Zig-Zag Problem, Testing for Randomness (including the Cake Display Test, which is a without-replacement test similar to the standard Empty Cell test), Waiting for Luggage at an Airport, Breakdowns in a Network, Learning Theory and Estimating the Number of Skeletons at an Archaeological Dig. Fundamental, reduction and covering theorems provide ways to reduce the number of calculations required. New combinatorial identities are discovered and a well-known one is proved in a combinatorial way for the first time. Some known results are derived from simple cases of the general models. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1309598 / Thesis (Ph.D.) -- University of Adelaide, School of Mathematical Sciences, 2007

L’électronique de puissance a un rôle de plus en plus grandissant dans les systèmes de transports : voitures électriques et hybrides, trains et avions. Pour ces applications, la sécurité est un point critique et par conséquent la fiabilité du système de puissance doit être optimisée. La connaissance du temps de fonctionnement avant défaillance est une donnée recherchée par les concepteurs de ces systèmes. Dans cette optique, un indicateur de défaillance précoce permettrait de prédire la défaillance des systèmes avant que celle-ci soit effective. Dans cette thèse, nous nous sommes intéressés à la caractérisation électromécanique des puces de puissance IGBT et MOSFET. L’exploitation de cette caractérisation devrait permettre, à plus long terme, de mettre en évidence un indicateur de l’état mécanique des assemblages de puissance à des fins de fiabilité prédictive. / Power electronics has a role increasingly growing up in transport:electric and hybrid vehicles, trains and aircraft. For these applications, security is a critical point, thus the reliability of the power assembly must be optimized. The knowledge of time to failure is very important information for the designers of these systems. Inthis context, an early failure indicator would predict system failuresbefore it becomes effective. In this thesis, we focused on the electromechanical characterization of power transistors: MOSFET and IGBT. Based on these results this electromechanical characterization should help us in the longer term, to highlight an early failure indicator of the power assembly.

Les séismes constituent une source d’aléas importante pour l’étude de la vulnérabilité d’unbâtiment. Le comportement parasismique des bâtiments à ossatures en bois est particulièrementintéressant. Deux familles de structure à ossature en bois peuvent être distinguées : les ossaturesutilisant les produits industriels que sont les panneaux en bois reconstitué servant à contreventerla structure et les connecteurs métalliques, et les ossatures traditionnelles avec remplissage reposantsur des techniques de construction anciennes et dépendantes du contexte local. L’efficacitédu comportement parasismique des bâtiments à ossature en bois traditionnels avec remplissagereste encore peu reconnue en raison du manque de résultats issus des travaux de recherche.Les travaux présentés dans cette thèse visent ainsi à améliorer les connaissances sur le comportementparasismique de cette typologie constructive. Partant de l’hypothèse selon laquellece comportement est gouverné par la réponse des assemblages par connecteurs métalliques, uneapproche multi-échelles, couplant études expérimentales et études numériques est développée.Elle détaille l’analyse à l’échelle 1 de la connexion, en passant par l’échelle 2 des cellules élémentaires,constitutives des murs, par l’échelle 3 des murs de contreventement pour se finaliserà l’échelle 4 du bâtiment dans son ensemble.Sur le plan expérimental, cette approche permet d’une part, de réaliser des études paramétriqueset ainsi d’appréhender l’influence de la réponse de chaque élément (bois, clous, feuillard,remplissage, contreventement, ouvertures) sur le comportement local (échelles 1 et 2) et global(échelles 3 et 4) de la structure. D’autre part, elle permet de fournir une base de données pourla validation des modélisations numériques aux différentes échelles.Sur le plan de la modélisation numérique, cette approche multi-échelles est fondée sur la priseen compte du comportement non-linéaire hystérétique des assemblages à l’échelle supérieure, parl’intermédiaire d’un macro-élément, développé dans la cadre de la méthode des éléments finis.Ainsi, grâce à une modélisation simplifiée (assemblage des macro-éléments), le calcul est rapide,aussi bien à l’échelle du mur qu’à celle du bâtiment, et intègre les phénomènes non-linéaire locaux.Le modèle peut ainsi prédire de manière relativement précise le comportement dynamique de lastructure complète à l’échelle 4, testée sur table vibrante.L’étude présentée dans ce manuscrit fait partie des travaux précurseurs relatifs à l’analysede la vulnérabilité sismique des ossatures bois avec remplissage. Cette étude débouche sur denombreuses perspectives pour l’analyse de cette typologie constructive. Elle confirme que les bâtimentsà ossatures en bois avec remplissage ont un comportement parasismique très performant. / The seismic vulnerabilty is an important issue in the design of a building. The seismicresistant behavior of timber-framed structures is particularly relevant. Two types of timberframedstructures can be distinguished : the timber-framed structures using industrial products,such as wood-products panels used to brace the structure or metal fasteners, and traditionaltimber-framed structures included infill made of natuarl materials (earth or stones masonry).The seismic resistant behavior efficiency of traditional structures remains poorly recognizedbecause of the lack of research results on this kind of construction.Therefore, the thesis aims at improving the seismic behavior knowledge of timber-framedmasonry. Based on the assumption that their behavior is driven by the response of the metalfasteners connections, a multi-scale approach is proposed. It couples experimental and numericalstudies. At the scale 1 of the connection, at the scale 2 of the elementary constitutive cell ofwalls, at the scale 3 of structural elements such as shear walls and finally at the scale 4 of theentire building.In regards to the experimental work, this method allows, on the one hand, to perform parametricstudies and to analyze the influence of each element (wood member, nails, steel strip,infill, bracing, openings) on the local behavior (scales 1 and 2) and on the global behavior(scales 3 and 4) of the structure. On the other hand, it allows to provide a database to validatethe numerical modeling at each scale.In regards to the numerical work, this multi-scale approach allows to take into account thehysteretic behavior of joints in the development of a macro-element at the scale 2. Thus, thanksto a simplified finite element modeling (macro-element assembly), the computational cost islimited and it allows to take into account the local phenomena. The model is able to predictrelatively accurately the dynamic behavior at the scale 4 of the building, tested on a shakingtable.The study, presented herein, is one of the pioneer work that deals with the analysis of theseismic vulnerability of timber-framed structures with infill panels. This study provides outlookfor the analysis of this type of buildings. It confirms that the timbered masonry structures havea relevant seismic resistant behavior.

Ce travail de recherche porte sur l’étude de l’effet du vieillissement par fatigue électrothermique sur la compatibilité électromagnétique des composants de puissance à base de carbure de silicium. Il est axé sur deux grandes parties ; une partie expérimentale et une autre plus orientée modélisation. Sur le plan expérimental, cette thèse étudie l’effet du vieillissement des transistors à base de carbure de silicium utilisés dans les convertisseurs statiques sur les perturbations électromagnétiques générées par ces convertisseurs. La deuxième partie porte sur la modélisation de ces transistors afin d’émuler l’effet de leur vieillissement sur les perturbations électromagnétiques des modules qu’ils composent. Cette dernière étape repose sur une étude de l’évolution des caractéristiques électriques statiques et dynamiques effectuées sur le composant sous test pour extraire les principaux paramètres intrinsèques du transistor de puissance dégradé après les séries de stress appliquées. En effet, ces paramètres intrinsèques dégradés émulent l’effet du vieillissement et sont représentatifs des principaux phénomènes pouvant influencer les convertisseurs de puissance étudiés. De ce fait, le changement de leurs valeurs dans le modèle du dit composant, décrit en VHDL-AMS et implémenté sur le simulateur de type circuit ANSYS SIMLORER, nous permet d’obtenir un modèle d’un tel composant après vieillissement. Cette étape a permis de valider la méthodologie développée pour la simulation des perturbations électromagnétiques conduites d’un composant sain dans un premier temps et d’un composant vieilli dans un second. Globalement, cette approche de modélisation innovante développée dans ce travail permet d’aider les concepteurs des convertisseurs statiques à prédire les perturbations électromagnétiques conduites avant et après vieillissement sans passer par la mesure et ses points faibles. Ceci apporte des informations complémentaires sur l’évolution des signatures CEM de tels modules durant sa durée de vie et d’estimer donc le risque lié au vieillissement des composants. / This research work focuses on the electrothermal aging effect on the electromagnetic compatibility of power components based on silicon carbide SiC. It focuses on two major parts ; an experimental part and another more oriented modelization. Experimentally, this thesis studies the aging effect of SiC transistors used in static converters on the electromagnetic interferences EMI generated by these converters. The second part deals with the modeling of these transistors in order to emulate the effect of their aging on the EMI of the modules they compose. This step made it possible to validate the methodology developed for the simulation of the conducted EMI of a healthy SiC MOFSET at first and of an aged SiC MOSFET in a second time. Overall, this innovative modeling approach developed in this work helps the designers of static converters to predict the conducted EMI before and after aging without going through the measurement. This provides additional information on the evolution of the EMC signatures of such modules during its lifetime and thus to estimate the risk associated with the aging of the components.

Es wird ein einfacher Berechnungsansatz für ein Baukastensystem aus Kastenprofilen verschiedener Querschnittsabmessungen erarbeitet. Diese Profile bestehen aus WVC (Wood Veneer Composites, Holzfurnierlagenverbundwerkstoffen). Der Ansatz bildet den statischen Lastfall und das Ermüdungsverhalten unter schwellende Dreipunktbiegung ab. Am Beispiel eines ausgewählten Strukturbauteils aus handelsüblichen Birkensperrholz wird der Berechnungsansatz konkretisiert und durch Versuche evaluiert. Aufbauend auf dem Kraft-Verformungsverhalten der analysierten Einzelbauteile und der kapillarporösen Struktur des Holzes wird bei dem Berechnungsansatz auf eine Analyse der Spannungen verzichtet. Stattdessen wird als Berechnungskriterium die kritische Normaldehnung in der Randfaser der Strukturbauteile genutzt. Weiterhin wird eine Methode vorgestellt um mittels niederzyklischen Ermüdungsversuchs (LCF, ca. 1e+03 Lastwechsel) den „Knickpunkt“ der Zeitfestigkeitslinie eines einstufigen Ermüdungsversuchs bei hohen Lastspielzahlen (HCF, 1e+06 bis 1e+07 Lastwechsel) für diese Strukturbauteile zu bestimmen. / It was developed a simple approach for the calculation of a modular construction system for box sections (profile structures) of different cross-sectional dimensions. These profile structures consists of WVC (Wood Veneer Composites). The approach maps the static load case and the fatigue behavior under pulsating three-point bending. By using a structural component made from commercial birch plywood, the calculation approach is specified and verified. Based on the force-deformation behavior of the analyzed single components in connection with the capillary-porous structure of the wood, the calculation approach dispense on an analysis of the tensions. Instead, a criterion, which calculates the critical normal strain in the outer fibers of the structural components, is used. Furthermore, a method of a low-cycle fatigue test (LCF, abbr. 1e+03 cycles) is presented. This method detects the “knee point" of the fatigue limit line for the profiles. That point is usually determined by the use of a high-cycle fatigue tests (HCF, 1e+06 until 1e+07 cycles).