In this study, ABS Publication 115, “Guidance on Fatigue Assessment of Offshore Structures” is briefly reviewed. Emphasis is on the S-N curves based fatigue assessment approach of non-tubular joints, and both size and environment effects are also considered. Further, fatigue tests are performed to study the fatigue strength of load-carrying and non-load-carrying steel cruciform joints that represent typical joint types in marine structures. The experimental results are then compared against ABS fatigue assessment methods, based on nominal stress approach, which demonstrates a need for better fatigue evaluation parameter. A good fatigue parameter by definition should be consistent and should correlate the S-N data well. The equivalent structural stress parameter is introduced to investigate the fatigue behavior of welded joints using the traction based structural stress approach on finite element models of specimens, and representing the data as a single Master S-N curve.

La résistance au cisaillement des éléments en béton armé reste un sujet d'un grand intérêt pour l'ingénierie des structures civiles. En service, la plupart des éléments structuraux sont soumis à des sollicitations de cisaillement et/ou de poinçonnement avec un risque accru de rupture fragile. Différentes méthodes de calcul des résistances à l’effort tranchant existent, mais présentent des dispersions considérables notamment pour les éléments structuraux non armés transversalement. Ceci est dû principalement à la non-prise en compte de l’ensemble des mécanismes entrant dans le phénomène de cisaillement. L’objectif du présent travail de thèse est de contribuer à la compréhension des mécanismes de transfert de l’effort tranchant dans les poutres en béton armé. Pour cela, une campagne expérimentale est réalisée sur des poutres en béton armé sans armatures transversales et de différentes tailles afin d’étudier l’effet d’échelle sur l’effort tranchant. Le processus de fissuration marqué par la présence d’une fissure diagonale est analysé par deux techniques expérimentales : Corrélation d’images numériques et l’émission acoustique. Par la combinaison des résultats de la corrélation d'images et les jauges de déformations collées sur les armatures longitudinales, il est possible de distinguer la contribution du mécanisme d’engrènement des granulats et de l'action d’effet de goujon. L’influence de l’effet d’échelle sur chaque mécanisme de transfert est analysée par des modèles numériques et empiriques simplifiés en se basant sur les résultats expérimentaux à l’échelle locale. Les résultats confirment que l’engrènement des granulats joue un rôle décisif dans la contribution à la résistance de cisaillement pour les éléments en béton armé sans armatures transversales. Cette contribution dépend essentiellement des variables cinématiques(ouverture de fissure et glissement) et l’angle d’inclinaison de la fissure diagonale. Ce mécanisme est très dépendant de la taille de l’élément et de la forme de la fissure. / The shear strength of reinforced concrete elements remains a subject of great interest for the civil engineering structures. During service,most structural elements are subjected to shear and /or punching stresses with an increased risk of brittle failure. Different methods of calculation of shear strengths exist but have considerable discrepancy especially for the structural elements without transverse reinforcement. It is mainly by not taking into consideration all the mechanisms which are involved in the shear behavior. The objective of thisdoctoral thesis is to contribute towards the understanding of the shear force transfer mechanisms in reinforced concrete beams. For this,an experimental campaign is carried out on reinforced concrete beams without transverse reinforcement and of different geometrically similar sizes in order to investigate the size effect on the shear force. The cracking process manifested by thepresence of a diagonal crack is analyzed by two experimental techniques: Digital Image Correlation and Acoustic Emission. By combining the results of the digital image correlation and the strain gauges glued on the longitudinal reinforcement, it is possible to distinguish the contribution of the aggregate interlocking mechanism and the dowel action on the transfer of shear forces. The influence of size effect on each transfer mechanism is analysed by simplified numerical and empirical models based on experimental results at the local scale. The results confirm that the aggregate interlocking mechanism plays a critical role in the contribution to shear strength for reinforced concrete elements without transverse reinforcement. This contribution depends essentially on the kinematic variables (crack opening and sliding) and the angle of inclination of the diagonal crack. This mechanism is strongly dependent on the size of the element and the shape of the crack.

Diversos materiais de interesse tecnológico podem ser considerados como materiais heterogêneos, onde sua natureza aleatória deve ser considerada para representar corretamente o comportamento não-linear. A avaliação quantitativa do dano em materiais sujeitos a estados de tensão ou deformação tem grande importância devido ao caráter crítico desse fenômeno, que pode crescer de forma abrupta e resultar em uma falha catastrófica da estrutura. Em estudos anteriores, Carpinteri e seus colaboradores apresentaram diferentes aspectos relacionados à caracterização do dano em materiais heterogêneos. Três desses aspectos são discutidos neste trabalho: (i) a proposta do número de fragilidade como medida da fragilidade da estrutura em análise; (ii) a evolução da dimensão fractal em que o processo de dano é desenvolvido; (iii) e os índices globais obtidos pela análise de Emissão Acústica (EA). Neste trabalho, uma versão do método dos elementos discretos formado por barras é utilizada para explorar esses aspectos. Espécimes de material quase-frágil são simulados e, quando possível, os resultados numéricos são comparados com resultados experimentais. Além disso, a discussão dos resultados obtidos é realizada visando compreender o comportamento desse tipo de material, como por exemplo, o fato de que estruturas com diferentes dimensões, porém com o mesmo número de fragilidade, têm comportamentos similares. Ademais, o método numérico empregado é apresentado como uma ferramenta viável para complementar a informação obtida em ensaios experimentais na avaliação do processo de dano. Pelo sinal de EA obtido através do método numérico empregado, obtiveram-se parâmetros para a classificação do tipo de falha e para o cálculo do tensor momento, onde comparando os resultados obtidos pelo modelo numérico e pela EA se observam comportamentos coerentes. / Several materials with technological interest can be considered as heterogeneous materials, where their random nature must be accounted to correctly represent the nonlinear behavior. The quantitative evaluation of damage in materials subjected to stress or strain states have great importance due to the critical nature of this phenomenon, which abruptly can rise to catastrophic failure. In previous studies, Carpinteri and his coworkers have presented different aspects of the damage process characterization in heterogeneous materials. Three of these aspects are discussed in this work: (i) the brittleness number proposal to measure the brittleness level of the analyzed structure, (ii) the relationship of the fractal dimension in which the damage process is developed, (iii) and the global indexes obtained by the Acoustic Emission (AE) analysis. In the present work, a version of discrete element method formed by bars is used to explore these concepts. A set of quasi-brittle material specimen is simulated and, when possible, the numerical results are compared with experimental ones. Moreover, a discussion of the obtained results is carried out aiming to understand the behavior of this kind of material, for instance, the fact that structures with different dimensions, but with the same brittleness number, have similar behavior. In addition, the numerical method is presented as a viable tool to complement information from experimental test on the damage process. From the AE signal obtained by the numerical method, parameters to classify the type of crack and for calculating the moment tensor were obtained, where consistent behaviors are observed by comparing the results of the numerical model and the AE.

abstract: One type of assistive device for the blind has attempted to convert visual information into information that can be perceived through another sense, such as touch or hearing. A vibrotactile haptic display assistive device consists of an array of vibrating elements placed against the skin, allowing the blind individual to receive visual information through touch. However, these approaches have two significant technical challenges: large vibration element size and the number of microcontroller pins required for vibration control, both causing excessively low resolution of the device. Here, I propose and investigate a type of high-resolution vibrotactile haptic display which overcomes these challenges by utilizing a ‘microbeam’ as the vibrating element. These microbeams can then be actuated using only one microcontroller pin connected to a speaker or surface transducer. This approach could solve the low-resolution problem currently present in all haptic displays. In this paper, the results of an investigation into the manufacturability of such a device, simulation of the vibrational characteristics, and prototyping and experimental validation of the device concept are presented. The possible reasons of the frequency shift between the result of the forced or free response of beams and the frequency calculated based on a lumped mass approximation are investigated. It is found that one of the important reasons for the frequency shift is the size effect, the dependency of the elastic modulus on the size and kind of material. This size effect on A2 tool steel for Micro-Meso scale cantilever beams for the proposed system is investigated. / Dissertation/Thesis / Doctoral Dissertation Systems Engineering 2019

本文嘗試利用涉險值（VaR）的估計來衡量投資組合風險和規模效果之間的關係。在歷史模擬法、變異-共變異法及極端值法估計VaR的結果中，皆得到小規模策略投資組合之可能損失風險額大於大規模策略投資組合。由VaR的估計，我們可得以下結論：規模溢酬和風險具有高度相關。小規模策略投資組合的風險高於大規模策略投資組合，故需具備較大規模策略投資組合為高之風險溢酬。 而投資人若進行買進小規模策略投資組合及賣出大規模策略投資組合，則因所承擔之風險較高，故所獲致優於大盤的績效，便在於彌補其所承擔的風險。此結果支持理性資產定價模式（Rational Asset Pricing）的論點。

規模效應是資本資產定價模型所無法解釋的報酬異常現象中，最常被討論的一個。本文首先將探討台灣股市是否具有規模效應情形，若有，再進一步檢視其型態為何。接下來，本文試圖了解是否公司發生財務危機的機率高低會與規模溢酬有所關連，亦即，小公司因為較容易發生財務危機事件，因此平均而言，較大公司有更高的報酬率。本研究將採用Shumway(2001)的羅吉斯迴歸模型來估算公司發生財務危機事件之機率，並且比較不同變數之預測能力如何。 經由實證結果，發現1986年至2009年的台灣股市具有規模效應情形，此結果與之前幾位研究者之研究結果相符。而在財務危機事件機率的部份，亦可看出發生財務危機機率較高的投資組合享有較高的報酬率，此情形在小市值規模的公司身上尤其明顯。從以上發現，我們可以推論財務危機風險確實為構成規模效應的因素之一。 / Size effect is one of wildly-discussed pricing anomalies that cannot be explained by capital assets pricing model, we would like to exam whether it exists in Taiwan stock markets and how its pattern is. Furthermore, we assume the higher financial distress risk a company has, the higher expected return it will earn. That is, there is positive correlation between financial distress risk and return. Following the logistic model developed by Shumway(2001), we explore the list of variables which have greater explanatory power in prediction. Through empirical data with stocks listed and ever listed on Taiwan Stock Exchange and GreTai Securities Market, we find size effect does exist. The result is consistent with previous study. We also see firms with higher distress risk tend to have higher returns, this condition is especially obvious in small companies. So we can infer that having higher distress risk is one of the reasons why small companies can earn higher returns, they are consistent with our conjecture.

<p>This study deals with one of the efficient market hypothesis’ anomaly. The research aims at proving the</p><p>existence of a size anomaly by answering the question: can you outperform the market by investing in</p><p>small and mid caps? It is in fact a questioning of the well-know efficient market hypothesis (EMH). We</p><p>investigate the size effect in the situation of a passive strategy with different indices (Russell Indices and</p><p>S&P Indices) from 1995 to 2005.</p><p>The introduction gives to the reader the background he needs to understand the methodology and the</p><p>approach of the issue by the authors. Key concepts are defined such as EMH, passive strategy.</p><p>The second part exposes the methodology the authors choose and the methodology of exploited indices.</p><p>The research consist on measuring the risk adjusting excess returns by comparing the market index</p><p>return (S&P 500 or Russell 3000) and the Small and Mid Caps indices (S&P Small Cap 600, S&P Mid</p><p>Cap 400, Russell Mid Cap and Russell 2000) over the period. Indeed the methodology of indices is</p><p>exposing in details to understand in which extent the study can be influence by the construction of</p><p>indices.</p><p>Then in part 3 the authors describe theories that are possible explanations for the size effect. Then it is</p><p>understandable that the size anomaly is the result of a set of factors that generate abnormal returns.</p><p>These theories help the authors to come up with a model that gives an overview of the research.</p><p>After having explained their research method and reveal their empirical findings. The authors</p><p>demonstrate that excess returns can be earned by investing in small and mid caps indices even after</p><p>controlling for risk. The risk adjusting excess returns their findings can potentially be explained by the</p><p>other factors depicted in the theoretical part. E/P ratios, Trading Costs, January effect, Overreaction are</p><p>possible reasons to explain the size anomaly. They also find an instability and/or reversal of the size</p><p>effect consistent with one of the theories. However the authors find data with non statistic significance,</p><p>so I accept the null hypothesis that the excess returns of small and mid caps indices are equal to zero.</p><p>The paper ends with a discussion about the limitations of the study and possible further researches. The</p><p>authors conclude that even if the existence of a size effect is obvious for some years and horizons of</p><p>investment, the passive strategy appears to be an unsuited method to take advantage of the small effect</p><p>since the results reject the null hypothesis. The authors clarify the fact that before investing in small and</p><p>mid caps, one has to be aware of all the factors that can influence his investment (beside risk) because</p><p>the size effect is a set of factors.</p><p>Key words: Efficient Market Hypothesis, Abnormal returns, Size effect (anomaly), Passive strategy,</p><p>Market Index, S&P indices, Russell indices</p>

Instrumented nanoindentation techniques have been widely used in characterizing mechanical behavior of materials in small length scales. For defect-free single crystals under nanoindentation, the onset of elastic-plastic transition is often shown by a sudden displacement burst in the measured load-displacement curve. It is believed to result from the homogeneous dislocation nucleation because the maximum shear stress at the pop-in load approaches the theoretical strength of the material and because statistical measurements agree with a thermally activated process of homogeneous dislocation nucleation. For single crystals with defects, the pop-in is believed to result from the sudden motion of pre-existing dislocations or heterogeneous dislocation nucleation. If the sample is prestrained before nanoindentation tests, a monotonic decrease of the measured pop-in load with respect to the increase of prestrain on Ni and Mo single crystals is observed. A similar trend is also observed that the pop-in load will gradually decrease if the size of indenter tip radius increases. This dissertation presents a systematic modeling endeavor of energetics and kinetics of defect initiation in the stressed volume at small scales. For homogeneous dislocation nucleation, an indentation Schmid factor is determined as the ratio of maximum resolved shear stress to the maximum contact pressure. The orientation-depended nanoindentation pop-in loads are predicted based on the indentation Schmid factor, theoretical strength of the material, indenter radius, and the effective indentation modulus. A good agreement has been reached when comparing the experimental data of nanoindentation tests on NiAl, Mo, and Ni, with different loading orientations to theoretical predictions. Statistical measurements generally confirm the thermal activation model of homogeneous dislocation nucleation, because the extracted dependence of activation energy on resolved shear stress is almost unique for all the indentation directions. For pop-in due to pre-existing defects, the pop-in load is predicted to be dependent on the defect density and the critical strength for heterogeneous dislocation nucleation. The cumulative probability of pop-in loads contains convoluted information from the homogenous dislocation nucleation, which is sensitive to temperature and loading rate, and heterogeneous dislocation nucleation due to the unstable change of existing defect network, which is sensitive to the initial defect distribution.

This study deals with one of the efficient market hypothesis’ anomaly. The research aims at proving the existence of a size anomaly by answering the question: can you outperform the market by investing in small and mid caps? It is in fact a questioning of the well-know efficient market hypothesis (EMH). We investigate the size effect in the situation of a passive strategy with different indices (Russell Indices and S&amp;P Indices) from 1995 to 2005. The introduction gives to the reader the background he needs to understand the methodology and the approach of the issue by the authors. Key concepts are defined such as EMH, passive strategy. The second part exposes the methodology the authors choose and the methodology of exploited indices. The research consist on measuring the risk adjusting excess returns by comparing the market index return (S&amp;P 500 or Russell 3000) and the Small and Mid Caps indices (S&amp;P Small Cap 600, S&amp;P Mid Cap 400, Russell Mid Cap and Russell 2000) over the period. Indeed the methodology of indices is exposing in details to understand in which extent the study can be influence by the construction of indices. Then in part 3 the authors describe theories that are possible explanations for the size effect. Then it is understandable that the size anomaly is the result of a set of factors that generate abnormal returns. These theories help the authors to come up with a model that gives an overview of the research. After having explained their research method and reveal their empirical findings. The authors demonstrate that excess returns can be earned by investing in small and mid caps indices even after controlling for risk. The risk adjusting excess returns their findings can potentially be explained by the other factors depicted in the theoretical part. E/P ratios, Trading Costs, January effect, Overreaction are possible reasons to explain the size anomaly. They also find an instability and/or reversal of the size effect consistent with one of the theories. However the authors find data with non statistic significance, so I accept the null hypothesis that the excess returns of small and mid caps indices are equal to zero. The paper ends with a discussion about the limitations of the study and possible further researches. The authors conclude that even if the existence of a size effect is obvious for some years and horizons of investment, the passive strategy appears to be an unsuited method to take advantage of the small effect since the results reject the null hypothesis. The authors clarify the fact that before investing in small and mid caps, one has to be aware of all the factors that can influence his investment (beside risk) because the size effect is a set of factors. Key words: Efficient Market Hypothesis, Abnormal returns, Size effect (anomaly), Passive strategy, Market Index, S&amp;P indices, Russell indices

Die Nanoindentation ist ein inzwischen etabliertes Verfahren zur Bestimmung der Materialkennwerte Härte und Elastizitätsmodul in kleinen Größendimensionen. Eine zusätzliche Bestimmung der Fließspannung aus solchen Nanoindentationsexperimenten würde deren Einsatzmöglichkeiten deutlich erweitern und zum Beispiel für die Bauteilauslegung kleiner Strukturen, Schichtcharakterisierung und die Beschaffung von Simulationseingangsdaten einen großen Fortschritt bedeuten. Diese Gründe machen das Thema zu einem aktuellen Forschungsgegenstand. In der vorliegenden Arbeit steht deswegen die Bewertung von Fließspannungsbestimmungsverfahren für Massivmaterialien in der Nanoindentation mittels einer Kombination aus Finite-Elemente-Simulationen und umfangreichen Experimentaldaten im Zentrum. Im Speziellen wird dabei das Konzept des effektiv geformten Indenters mit dem erweiterten Hertzschen Ansatz und dessen Anwendung zur Fließspannungsbestimmung aus Eindringversuchen mit selbstähnlichen Berkovichpyramiden betrachtet. Zur Bearbeitung dieser Aufgabenstellung wurden unter anderem drei Referenzverfahren zur Fließspannungsbestimmung (die Expanding cavity-Modelle, das Loading partial unloading-Verfahren und Minidruckversuche) ausführlich charakterisiert. Damit konnten dann im Weiteren belastbare Referenzfließspannungen für die umfangreiche Experimentaldatenbasis zur Verfügung gestellt werden. Außerdem wurden die untersuchten Materialien auf den Einfluss der Größenabhängigkeit der Fließspannungen, den Indentation size effect, hin untersucht. Dabei wurden die vorliegenden physikalischen Vorgänge in den Proben beschrieben, dahingehende Unterschiede bei den betrachteten Referenzverfahren charakterisiert und den Fließspannungswerten die Fließzonendimensionen zugeordnet. Mit den damit zur Verfügung stehenden Informationen konnte das Konzept des effektiv geformten Indenters in seiner Anwendung zur Fließspannungsbestimmung grundlegend bewertet werden. Alle Untersuchungen wurden dabei stets parallel mit Hilfe von Simulations- und Experimentaldaten durchgeführt, um tiefere Einblicke in die zu Grunde liegende Mechanik der Fließprozesse zu gewinnen.