54 resultados para Er Stress


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Due to functional requirement of a structural detail brackets with and without scallop are frequently used in bridges, decks, ships and offshore structure. Scallops are designed to serve as passage way for fluids, to reduce weld length and plate distortions. Moreover, scallops are used to avoid intersection of two or more welds for the fact that there is the presence of inventible inherent initial crack except for full penetrated weld and the formation of multi-axial stress state at the weld intersection. Welding all around the scallop corner increase the possibility of brittle fracture even for the case the bracket is not loaded by primary load. Avoiding of scallop will establish an initial crack in the corner if bracket is welded by fillet welds. If the two weld run pass had crossed, this would have given a 3D residual stress situation. Therefore the presences and absence of scallop necessitates the 3D FEA fatigue resistance of both types of brackets using effective notch stress approach ( ). FEMAP 10.1 with NX NASTRAN was used for the 3D FEA. The first and main objective of this research was to investigate and compare the fatigue resistance of brackets with and without scallop. The secondary goal was the fatigue design of scallops in case they cannot be avoided for some reason. The fatigue resistance for both types of brackets was determined based on approach using 1 mm fictitiously rounded radius based on IIW recommendation. Identical geometrical, boundary and loading conditions were used for the determination and comparison of fatigue resistance of both types of brackets using linear 3D FEA. Moreover the size effect of bracket length was also studied using 2D SHELL element FEA. In the case of brackets with scallop the flange plate weld toe at the corner of the scallop was found to exhibit the highest and made the flange plate weld toe critical for fatigue failure. Whereas weld root and weld toe at the weld intersections were the highly stressed location for brackets without scallop. Thus weld toe for brackets with scallop, and weld root and weld toe for brackets without scallop were found to be the critical area for fatigue failure. Employing identical parameters on both types of brackets, brackets without scallop had the highest except for full penetrated weld. Furthermore the fatigue resistance of brackets without scallop was highly affected by the lack of weld penetration length and it was found out that decreased as the weld penetration was increased. Despite the fact that the very presence of scallop reduces the stiffness and also same time induce stress concentration, based on the 3D FEA it is worth concluding that using scallop provided better fatigue resistance when both types of brackets were fillet welded. However brackets without scallop had the highest fatigue resistance when full penetration weld was used. This thesis also showed that weld toe for brackets with scallop was the only highly stressed area unlike brackets without scallop in which both weld toe and weld root were the critical locations for fatigue failure when different types of boundary conditions were used. Weld throat thickness, plate thickness, scallop radius, lack of weld penetration length, boundary condition and weld quality affected the fatigue resistance of both types of brackets. And as a result, bracket design procedure, especially welding quality and post weld treatment techniques significantly affect the fatigue resistance of both type of brackets.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The main purpose of this study was to analyze how stress tests are used in risk management in the Finnish banking and insurance sectors. In order to enhance understanding of the topic, stress testing was explored in the context of corporate governance and regulato-ry implications of Basel II and Solvency II on stress testing were examined. In addition, the effects of the global financial crisis on stress testing were mapped and the differences in stress testing practices between the banking and insurance sector were discussed. The research method was qualitative case study and it was conducted by interviewing risk managers from ten institutions and a representative from FIN-FSA. Findings pointed out that stress testing practices vary significantly between different institutions. Interesting observations were made in terms of stress testing practices in the banking and insurance sectors. The increasing importance and use of stress tests were recognized as a result of the financial crisis. Stress testing was even considered more like art than science given the amount of challenges it involves. In general, improvements in stress tests were suggested, with an emphasis on stress concentration between different types of risks.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In the Russian Wholesale Market, electricity and capacity are traded separately. Capacity is a special good, the sale of which obliges suppliers to keep their generating equipment ready to produce the quantity of electricity indicated by the System Operator. The purpose of the formation of capacity trading was the maintenance of reliable and uninterrupted delivery of electricity in the wholesale market. The price of capacity reflects constant investments in construction, modernization and maintenance of power plants. So, the capacity sale creates favorable conditions to attract investments in the energy sector because it guarantees the investor that his investments will be returned.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The purpose of this thesis is to develop a theory model about some core concepts and phenomena within caritative ethics when patients' demands are existential. There are two research questions, (A) Which realities represent concepts such courage, responsibility, and sacrifice within the caritative ethics. (B) Which phenomena of ethical significance are made current and applicable when patients¿ demands are existential. This study takes as its point of departurecertain chosen theoretical perspectives that discuss some perspectives of the concepts of courage, responsibility, and sacrifice in terms of their significanceto the research questions A. This represents the study¿s theoretical data. The empirical data provide answers to the research question B. In the end, the thesis discusses synthesis of these two accesses of knowledge in order to formulate theses and create a theory model. Løgstrup's contribution and description of the ethical claim helps in understanding and interpreting the links between the substance of the caritative ethic and the concrete reality in the encounter with existential issues. This thesis is a study within the field of Caring Science. The nursing profession provides empirical data and reflects the study topic, by addressing issues of relevance to the application of the knowledge of Caring Sciencein light of the nursing profession's various daily challenges. This study proceeds from the basic assumption: "Caring relationships form the meaningful contextfor caring and derive from the ethos of love, responsibility, and sacrifice, i.e. a caritative ethics" (Eriksson 2001). This study attempts to explore and prove this statement in the light of theoretical and empirical data, in the light ofthe caring scientific perspective which is here linked particularly to the viewof man as a unity of body, mind, and soul, and to the ontological health model. Hermeneutics is the overall perspective for the interpretations proposed in this thesis. Through conversation and hermeneutic observations, I try to understandthe challenges of nursing performance in the encounter with existential issues. This constitutes the empirical data that was gathered on a ward treating cancerpatients. The discussion proceeds sequence by sequence, first by discussing theconditions of the caritative ethics when meeting the existential claims in the light of the concepts of courage, sacrifice, and responsibility. Then a thesis is formulated concerning the caritative ethics in the light of Caring Science. This is the foundation of the creation of the theory model. The resulting theses concern the chosen concepts and phenomena which promote caritative ethics when patients' claims are existential: Freedom is the hallmark of caritative ethics. Freedom is the basic category of caring. When attending to the patient's existential claims, it is of vital importance to secure human relationships as caring interpersonal communions, created by responsible persons who have shown courage and sacrifice. Courage and sacrifice constitute the ethos of caring communities (communions). Courage and sacrifice are then a part of the collective ethos of caring communities, because the patient is confirmed as the unity of body, mind, and soul.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Myös HMV V154.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Myös Gramophone 83257.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Broschyr om Närings-, trafik- och miljöcentralerna.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Kirjallisuusarvostelu

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The fatigue failure of structures under fluctuating loads in fillet weld joints raises a demand to determine the parameters related to this type of loading. In this study, the stress distribution in the susceptible area of weld toe and weld root in fillet welded models analyzed by finite element method applying FEMAP software. To avoid the geometrical singularity on the path of analytical stress analysis in the toe and root area of a weld model the effective notch stress approach applied by which a proper fictitious rounding that mostly depend on the material of structure is applied. The models with different weld toe waving width and radius are analyzed while the flank angle of weld varied in 45 and 30 degrees. The processed results shows that the waving compare to the straight weld toe makes differences in the value of stress and consequently the stress concentration factor between the tip and depth of the waves in the weld toe which helps to protect the crack of propagation and gives enough time and tools to be informed of the crack initiation in the structure during the periodical observation of structure. In the weld root study the analyses among the models with the welding penetration percentage from non-penetration to the full-penetration shows a slightly increase in the root area stress value which comparing with the stiffening effect of penetration conclude that the half-penetration can make an optimization between the stress increase and stiffening effect of deep penetration.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Roll-to-Roll process makes it possible to print electronic products continuously onto a uniform substrate. Printing components on flexible surfaces can bring down the costs of simple electronic devices such as RFID tags, antennas and transistors. The possibility of quickly printing flexible electronic components opens up a wide array of novel products previously too expensive to produce on a large scale. Several different printing methods can be used in Roll-to-Roll printing, such as gravure, spray, offset, flexographic and others. Most of the methods can also be mixed in one production line. Most of them still require years of research to reach a significant commercial level. The research for this thesis was carried out at the Konkuk University Flexible Display Research Center (KU-FDRC) in Seoul, Korea. A system using Roll-to-Roll printing requires that the motion of the web can be controlled in every direction in order to align different layers of ink properly. Between printers the ink is dried with hot air. The effects of thermal expansion on the tension of the web are studied in this work, and a mathematical model was constructed on Matlab and Simulink. Simulations and experiments lead to the conclusion that the thermal expansion of the web has a great influence on the tension of the web. Also, experimental evidence was gained that the particular printing machine used for these experiments at KU-FDRC may have a problem in controlling the speeds of the cylinders which pull the web.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The dissertation ´I knit, therefore I am!´ Learning and identity in informal space has two main purposes. The first purpose being an investigation of how new value attributions and thinking can generate novel and usable knowledge to the field of craftsmanship, and the second purpose being a display of a different and overlooked philosophical and cultural potential in a reflexive mode of expression, which is able to reflect the normative comprehension of craftsmanship. The dissertation focuses on learning and identity in informal spaces of learning and how it is possible to relate such a learning perspective to crafts training in educational establishments. The empirical foundation of this dissertation is ‘craftivism’. In the dissertation activists from the Nordic countries have been interviewed about what they do when they put up their textile graffiti on lamp posts and house walls. Three research problems are presented: 1) What stories do people who work as crafts activists, tell about ways of relating and methods of action when they make crafts? 2) What do these stories tell about learning and identity? 3) How may the research results influence training and education in craftsmanship? These questions are being asked in order to acquire new knowledge in two aspects; first aspect being knowledge about crafts in relation to techniques, tradition and the objects in crafts, and the second aspect being knowledge about learning and identity in informal spaces of learning. The dissertations theoretical foundation is post structural and sociocultural combined with hermeneutical-inspired qualitative interviews. The author’s position and pre-understanding is subject to discussion in relation to the informant; the performing activist, as the background for both of them is craftsmanship. Starting from cultural studies, it is possible to see the activist subject’s conditions of possibilities in the culture, as the activism of the sub-cultural phenomenon’s craft lights up through a performing approach to the individual’s actions. First the research material has been analysed for events of textile graffiti and possible themes in the events, after which the results have been summarised. Next the research material has been analysed for events about learning and identity due to the author’s wish of comprehending the background of and motivational force in activism. The analysis is divided in main perspectives with different dimensions. The results of the analysis show the activist subject’s construction of an individual who actively takes part in a community by e.g. creating joy, changing the world’s perception of sustainability or by feminizing the public space. By taking crafts over the borders (and away from the class room) crafts become contextualized in a novel fashion thus obtaining an independent status. In this fashion the dissertation writes itself into a new method of comprehending and performing traditional craftsmanship techniques.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Modern machine structures are often fabricated by welding. From a fatigue point of view, the structural details and especially, the welded details are the most prone to fatigue damage and failure. Design against fatigue requires information on the fatigue resistance of a structure’s critical details and the stress loads that act on each detail. Even though, dynamic simulation of flexible bodies is already current method for analyzing structures, obtaining the stress history of a structural detail during dynamic simulation is a challenging task; especially when the detail has a complex geometry. In particular, analyzing the stress history of every structural detail within a single finite element model can be overwhelming since the amount of nodal degrees of freedom needed in the model may require an impractical amount of computational effort. The purpose of computer simulation is to reduce amount of prototypes and speed up the product development process. Also, to take operator influence into account, real time models, i.e. simplified and computationally efficient models are required. This in turn, requires stress computation to be efficient if it will be performed during dynamic simulation. The research looks back at the theoretical background of multibody dynamic simulation and finite element method to find suitable parts to form a new approach for efficient stress calculation. This study proposes that, the problem of stress calculation during dynamic simulation can be greatly simplified by using a combination of floating frame of reference formulation with modal superposition and a sub-modeling approach. In practice, the proposed approach can be used to efficiently generate the relevant fatigue assessment stress history for a structural detail during or after dynamic simulation. In this work numerical examples are presented to demonstrate the proposed approach in practice. The results show that approach is applicable and can be used as proposed.