Dissertations / Theses on the topic 'DUCTILE DESIGN'

The research promotes a better understanding of the response of torsionally unrestrained and restrained ductile systems by examining the mechanism developed during the torsional response of systems as they are affected by the dynamic actions of the translational and rotational mass. A simple but effective design strategy for the seismic design of torsionally asymmetric systems is suggested based on the estimate of the system displacement ductility capacity and the distribution of the estimated system strength to its elements. The strength eccentricity is considered the main parameter to influence the ductile response of asymmetric systems. The possible success of the design strategy to limit displacement demands of the elements to less than their displacement ductility capacity, for zero and increasing strength eccentricities, was examined against the effects of key parameters expected to influence response. These parameters are: strength eccentricity and the associated increase of system strength, mass eccentricity, ratio of radii of gyration of strength and mass, reduced system displacement ductility capacity, transverse elements and their degree of torsional restraint, the ratio of element nominal yield displacement, i.e., α=Δye2/Δye1. and associated stiffness eccentricity, uncoupled translational period, consideration of different earthquake records and their direction of application. Elements are modelled with a realistic relationship between element strength, stiffness and nominal yield displacement. The stiffness is strength dependant and the nominal yield displacement is a geometric and material property independent of strength. The centre of strength and stiffness are, therefore, not independent parameters. This research focuses on analytical studies of torsionally unrestrained and restrained single-mass asymmetric systems. Single, two and multi-element systems were examined. An experimental programme was also undertaken on single-mass models to verify some of the analytical findings. The findings suggest that the suggested design strategy is successful in limiting the displacement demands on elements to less than their displacement capacity for zero and increasing strength eccentricities. No differentiation is required between systems having or not having mass eccentricity. The proposed design strategy is slightly different for torsionally unrestrained and restrained systems. It promises to be straightforward, rational and in terms of design efforts most user friendly.

In order to produce economical seismic designs, the modern building codes allow reducing seismic design forces if the seismic force resisting system (SFRS) of a building is designed to develop an identified mechanism of inelastic lateral response. The capacity design aims to ensure that the inelastic mechanism develops as intended and no undesirable failure modes occur. Since the 1984 edition, this design approach is implemented in the Canadian Standards Association (CSA) standard A23.3 for seismic design of ductile reinforced concrete (RC) shear walls with the objectives of providing sufficient flexural and shear strength to confine the mechanism to the identified plastic hinges and ensure a flexure-governed inelastic lateral response of the walls. For a single regular wall, the implemented capacity design requirements assume a lateral deformation of the wall in its fundamental lateral mode of vibration, and hence aim to constrain the inelastic mechanism at the expected base plastic hinge. This design is referred to as single plastic-hinge (SPH) design. Despite these requirements, CSA standard A23.3 did not prescribe, prior to the 2004 edition, any methods for determining capacity design envelopes for flexural and shear strength design of ductile RC shear walls over their height. Only its Commentary recommended such methods. However, various studies suggested, mainly for cantilever walls, that the application of these methods could result in multistorey wall designs experiencing the formation of unintended plastic hinges at the upper storeys and a high potential of undesirable shear failure, principally at the wall base, jeopardizing the intended ductile flexural response of the wall. These design issues result from an underestimation of dynamic amplification due to lateral modes of vibration higher than the fundamental lateral mode. The 2004 CSA standard A23.3 now prescribes capacity design methods intending in part to address these design issues. Although these methods have not been assessed yet, their formulation appears deficient in accounting for the higher mode amplification effects. In this regard, this research project proposes for CSA standard A23.3 new capacity design methods, considering these effects, for a SPH design of regular ductile RC cantilever walls used as SFRS for multistorey buildings. In order to achieve this objective, first a seismic performance assessment of a realistic ductile shear wall system designed according to the 2004 CSA standard A23.3 is carried out to assess the prescribed capacity design methods. Secondly, an extensive parametric study based on sophisticated inelastic dynamic simulations is conducted to investigate the influence of various parameters on the higher mode amplification effects, and hence on the seismic force demand, in regular ductile RC cantilever walls designed with the 2004 CSA standard A23.3. Thirdly, a review of various capacity design methods proposed in the current literature and recommended by design codes for a SPH design is performed. From the outcomes of this review and the parametric study, new capacity design methods are proposed and a discussion on the limitations of these methods and on their applicability to various wall systems is presented.

This thesis is concerned with the effects of lateral confining reinforcement on the ductile behaviour of reinforced concrete columns. The contents of the chapters are summarized as follows. In Chapter one, the general problems in seismic design are discussed and earthquake design methods based on the ductile design approach are described. Japanese, New Zealand and United States design codes are compared. Finally, the scope of this research project is outlined. In Chapter two, after reviewing previous research on confined concrete, the factors which affect the effectiveness of lateral confinement are discussed. Especially the effects of the yield strength of transverse reinforcement, the compressive strength of plain concrete and the strain gradient in the column section due to bending are discussed based on tests which were conducted by the author et al at Kyoto University and Akashi Technological College, Japan. In the axial compression tests on spirally reinforced concrete cylinders (150 mm in diameter by 300 mm in height), the yield strength of transverse reinforcement and the compressive strength of plain concrete were varied from 161 MPa to 1352 MPa and from 17 MPa to 60 MPa, respectively, as experimental parameters. It is found that, when high strength spirals are used as confining reinforcement, the strength and ductility of the confined core concrete are remarkably enhanced but need to be estimated assuming several failure modes which could occur. These are based on the observations that concrete cylinders with high strength spirals suddenly failed at a concrete compressive strain of 2 to 3.5 % due to explosive crushing of the core concrete between the spiral bars or due to bearing failure of the core concrete immediately beneath the spiral bars, while the concrete cylinders with ordinary strength spirals failed in a gentle manner normally observed. In addition, eccentric loading tests were conducted on concrete columns with 200 mm square section confined by square spirals. It is found that the effectiveness of confining reinforcement is reduced by the presence of the strain gradient along the transverse section of column. In Chapter three, the effectiveness of transverse reinforcement with various types of anchorage details which simplify the fabrication of reinforcing cages are investigated. Eight reinforced concrete columns, with either 400 mm or 550 mm square cross sections, were tested subjected to axial compression loading and cyclic lateral loading which simulated a severe earthquake. The transverse reinforcement consisted of arrangements of square perimeter hoops with 135° end hooks, cross ties with 90° and 135° or 180° end hooks, and 'U' and 'J' shaped cross ties and perimeter hoops with tension splices. Conclusions are reached with regard to the effectiveness of the tested anchorage details in the plastic hinge regions of columns designed for earthquake resistance. In Chapter four, the effectiveness of interlocking spirals as transverse reinforcement is studied. Firstly, the general aspects and the related problems of interlocking spirals to provide adequate ductility in the potential plastic hinge region of columns are discussed, referring to the provisions in the New Zealand code,the CALTRANS (California Transportation Authority) code and other related codes. Secondly, based on those discussions, a design method to securely interlock the spirals is proposed. Thirdly, the effectiveness of interlocking spirals is assessed based on column tests conducted as part of this study. Three columns with interlocking spirals and, for comparison, one rectangular column with rectangular hoopsandcross ties, were tested under cyclic horizontal loading which simulated a severe earthquake. The sections of those columns were 400 mm by 600 mm. In Chapter five, analytical models to investigate the buckling behaviour of longitudinal reinforcement restrained by cross ties with 90° and 135° end hooks and by peripheral hoops are proposed. The analyzed results using the proposed models compare well with the experimental observations described in Chapter three. Using those proposed models, a method to check the effectiveness of cross ties with 90° and 135° end hooks is proposed for practical design purposes. In Chapter six, a theory for the prediction of the ultimate longitudinal compressive concrete strain at the stage of first hoop fracture referred to as the "Energy Balance Theory", which has been developed by Mander, Priestley and Park at University of Canterbury, is introduced. After discussing the problems in the "Energy Balance Theory", a modified theory for the prediction of the ultimate longitudinal compressive concrete strain at the stage of first hoop fracture is proposed. The predictions from the modified theory are found to compare well with previous experimental results.

Inelastic design methods have been used in seismic design for several years and are well accepted in engineering practice. In contrast, an inelastic wind design method is yet to be developed, in part due to the inherent differences between seismic forces and wind forces. Current wind design practice follows a linear method to find a design windspeed for the location where the structure will be built. Once the design windspeed has been determined, the lateral force resisting system is designed such that it will behave elastically. This study was conducted with the hypothesis that by providing ductility at the material level, member level, and system level it may be possible to use a reduced design force for wind (i.e., a design force reduction that is proportional to a wind response modification factor). A three-story office building that uses steel moment frames as the primary lateral force resisting system was examined to test the hypothesis. Various levels of ductility were included based on ductility requirements for material strength, section stability and system stability originally developed for seismic design. Moment frames were designed for a range of design windspeeds and for three levels of ductility. For each design windspeed, a non-ductile (representing the moment frame as it would be designed by current standards), moderately-ductile and highly-ductile moment frame were developed. A finite element model of the building was made to capture inelastic material behavior and large displacements. The finite element model was subjected to wind loads based on wind tunnel tests data, and the static pushover, vibration, and dynamic responses of the building were evaluated. The performance of each moderately-ductile and highly-ductile moment frame was compared to the performance of each non-ductile frame of a higher design windspeed. The results show that for moderately-ductile moment frames, a wind response modification factor equal to 2 provided a collapse capacity that met or exceeded the collapse capacity of the comparative nonductile moment frame. For highly-ductile moment frames, a wind response modification factor equal to 3 met or exceeded the collapse capacity of the comparative non-ductile moment frame. In many instances, the collapse capacity of the moderately-ductile moment frame was similar to the collapse capacity of the highly-ductile moment frame. Thus, the results indicate that the use of a response modification factor for wind may be viable.

The aim of the project is to develop a model, which is going to be used for mass reduction of a standard profile of aluminium seat rails in Aircraft structure. Using nonlinear analysis including plasticity and material failure laws the effect of changes in geometry vs. ultimate load is analysed (ABAQUS 6.11). First, the non-linear model used is validated with experimental testing: Boundary conditions and material properties are adjusted based on load displacement curves, strain gauges information and failure patterns. Less than 1% deviation is achieved between simulation and testing. An inclusion of material imperfection led to a 5% improvement of the results. Using the validated algorithm, a mass reduction is performed via geometry variation
Ziel der Studie ist es ein adäquates Simulationsmodell zu entwickeln, welches zur Gewichtsreduzierung einer Standardprofil Aluminium Sitzschiene im Flugzeug verwendet werden kann. In einer nichtlinearen Analyse unter Berücksichtigung der Plastizität des Materials und von Materialfehlern wird die Auswirkung der Geometrieänderungen auf die maximale Traglast analysiert (ABAQUS 6.11). Zunächst wird das nicht-lineare Modell mit experimentell ermittelten Daten überprüft: Randbedingungen und Materialeigenschaften werden basierend auf Lastverschiebungskurven, Informationen von Dehnungsmessstreifen und Versagensmustern angepasst. Dabei wurden weniger als 1% Abweichung zwischen Simulation und Test erzielt. Die Berücksichtigung von Materialfehlern führte zu einer 5%-igen Verbesserung der Ergebnisse. Mit dem validierten Modell wird abschließend eine Gewichtsreduzierung mittels Geometrievariation durchgeführt

Non-ductile reinforced concrete frame buildings constitute an important part of the vulnerable buildings in seismic regions of the world. Collapse of non-ductile multi story concrete buildings during strong earthquakes in the past resulted in severe casualties and economic losses. Their rehabilitation through retrofitting is a critical issue in reducing seismic risks worldwide. A displacement-based retrofitting approach is presented in this study for seismic retrofitting of medium height non-ductile concrete frames. A minimum amount of shear walls are added for maintaining the deformation levels below the critical level dictated by the existing columns in the critical story, which is usually at the ground story. Detailing of shear walls are based on conforming to the reduced deformation demands of the retrofitted frame/wall system. Member-end rotations are employed as the response parameters for performance evaluation. Initial results obtained from the proposed displacement based approach have revealed that jacketing of columns and confining the end regions of added shear walls are usually unnecessary compared to the conventional force-based approach, where excessive force and deformation capacities are provided regardless of the actual deformation demands.

This thesis documents an investigation of the use of the roof diaphragm flexibility in the seismic design and analysis procedure of single-storey steel buildings designed otherwise in accordance with the provisions of the 2010 NBCC and the 2009 CSA S16. The design approach considers the members of the vertical bracing system as the ductile fuse elements in the seismic force resisting system (SFRS), whereas the diaphragm remains elastic. An alternative design approach was also examined in which the steel deck roof diaphragm acts as a ductile fuse element in the SFRS; at present this procedure is not permitted by the NBCC or CSA S16. The investigation was reliant on a complementary three phase test program in which nineteen large-scale roof diaphragm specimens were dynamically excited with a sequence of increasing amplitude loading protocols. The first part of the study comprised the development of a deep horizontal plane truss numerical model using the OpenSees software platform to reproduce the dynamic characteristics as well as the elastic and inelastic response of the nineteen test specimens. The predicted fundamental period of vibration, the elastic response and the inelastic hysteretic response were compared with the test results and the models were calibrated accordingly. In the second part of the study, the detailed design and non-linear time history dynamic analyses of representative medium size and large size single-storey steel buildings were carried out. The intent was to evaluate the overall behaviour of four structural systems whose design was tailored to either rely on the flexibility of the diaphragm or to allow the roof decking / connections to deform inelastically. OpenSees building models were developed by integrating a non-linear brace model with the non-linear diaphragm model. Dynamic analyses were performed on the designed buildings using the corresponding OpenSees building model and responses were evaluated under a suite of design level earthquake signals. The study illustrated that the analytically predicted fundamental period of vibration which includes the influence of the roof deck diaphragm could be used in the design of such single-storey steel buildings. This finding leads to the recommendation to revise the expression given in 2010 NBCC for the fundamental period of vibration as well as for the period limitation. Further, compared to the different structural systems, the buildings designed with EBF structural system were found most promising in terms of the relative capacity force on the steel deck diaphragm and the building response. The study also found that the diaphragms in the EBF and CBF structural systems could be designed for the force corresponding to the seismic base shear with RdRo = 2, if it controls the design. Moreover, significant shear strength degradation and concentration of inelastic demand were observed in the diaphragm at the edge of the buildings when the steel decks were parallel to the loading direction and the diaphragm was designed as a ductile fuse element. This illustrates that the value of 2.0 that was assumed for the seismic force reduction parameter Rd may not be appropriate in the design of such buildings. Similar strength degradation and concentration of inelastic demand in the diaphragm were observed in the buildings with a Type CC structural system, which shows that the diaphragm may need to be designed corresponding to the elastic seismic force.
La présente thèse porte sur une recherche sur l'utilisation de la flexibilité du diaphragme de toit dans la conception et l'analyse parasismiques des bâtiments d'un seul étage en acier conçus selon les dispositions parasismiques des normes de construction CNBC 2010 et CSA S16-09. L'approche de conception consiste à considérer les diagonales de contreventement faisant partie du système de résistance aux forces sismiques (SRFS) comme les éléments ductiles, alors que le comportement du diaphragme de toit demeure dans le domaine élastique. Une approche différente a aussi été examinée selon laquelle le diaphragme de toit en acier agit comme un élément ductile dans le SFRS, approche qui n'est pas autorisée dans les codes CNBC et CSA S16 présentement en vigueur. L'étude est tributaire d'un programme d'essais complémentaires en trois phases durant lequel dix-neuf spécimens de diaphragme de toit à grande échelle ont été soumis à des essais dynamiques selon un protocole de chargement à amplitude variable. La première partie de l'étude a porté sur l'élaboration avec le logiciel OpenSees d'un modèle numérique de diaphragme de toit composé d'un système de treillis afin de reproduire les caractéristiques dynamiques de même que les comportements élastique et inélastique des dix neuf spécimens. Les prédictions de la période fondamentale de vibration, du comportement élastique et de la réponse sous sollicitation inélastique cyclique ont été comparées aux résultats des essais au laboratoire, et les modèles ont été ajustés en conséquence. Dans le seconde partie du programme d'essais, la conception de différents bâtiments à un étage de taille moyenne et de taille grande, ainsi que l'analyse non-linéaire de ceux-ci, a été complétée. L'objectif était d'évaluer le comportement global de quatre systèmes structuraux dont la conception avait été adaptée pour prendre en compte la flexibilité du diaphragme de toit ou permettre les déformations inélastiques des connecteurs du tablier métallique. Des modèles des bâtiments ont été développés avec le logiciel OpenSees, en intégrant un modèle non linéaire des diagonales et le modèle non linéaire du diaphragme. Des analyses dynamiques des bâtiments ainsi conçus ont été réalisées avec le logiciel OpenSees et leur comportement a été évalué sous un ensemble de mouvements de sol sismique d'amplitude correspondant au niveau sismique de conception. L'étude à démontré que la période qui inclus l'influence du diaphragme peut être utilisée dans la conception d'un bâtiment à un étage en acier avec ce type de construction. Cette découverte mène à la recommandation de réviser l'expression du CNBC 2010 pour la période fondamentale du bâtiment ainsi que la limite empirique sur celle-ci. Les bâtiments construits avec un système de contreventements de type excentrique sont les plus prometteurs au niveau de la capacité relative du diaphragme en acier et la comportement du bâtiment. L'étude a aussi démontré que les diaphragmes qui sont unis avec un système de contreventements concentriques ou excentriques peuvent êtres conçus pour la force qui correspond au cisaillement calculé avec RdRo = 2, si celui-ci contrôle la conception du diaphragme. Il faut aussi noter qu'une dégradation significative de la capacité en cisaillement et une concentration de la demande élastique à été observée aux côtés des bâtiments quand la tôle est installée parallèle à la direction de la charge et quand le diaphragme est conçu comme l'élément sacrifiant. Ceci illustre le fait que la valeur de 2.0 assumé pour la ductilité du système (Rd) n'est pas nécessairement appropriée pour la conception de ce genre de bâtiments. Cette même concentration de la demande aux côtes et dégradation du système a aussi été observée dans les bâtiments conçus avec un système latéral de type 'construction conventionnelle' ce qui veut dire que le diaphragme devrait sans doute être construit pour la force sismique élastique.

Use of fiber reinforced polymer (FRP) material has been a good solution for many problems in many fields. FRP is available in different types (carbon and glass) and shapes (sheets, rods, and laminates). Civil engineers have used this material to overcome the weakness of concrete members that may have been caused by substandard design or due to changes in the load distribution or to correct the weakness of concrete structures over time specially those subjected to hostile weather conditions. The attachment of FRP material to concrete surfaces to promote the function of the concrete members within the frame system is called Externally Bonded Fiber Reinforced Polymer Systems. Another common way to use the FRP is called Near Surface Mounted (NSM) whereby the material is inserted into the concrete members through grooves within the concrete cover. Concrete beam-column joints designed and constructed before 1970s were characterized by weak column-strong beam. Lack of transverse reinforcement within the joint reign, hence lack of ductility in the joints, and weak concrete could be one of the main reasons that many concrete buildings failed during earthquakes around the world. A technique was used in the present work to compensate for the lack of transverse reinforcement in the beam-column joint by using the carbon fiber reinforced polymer (CFRP) sheets as an Externally Bonded Fiber Reinforced Polymer System in order to retrofit the joint region, and to transfer the failure to the concrete beams. Six specimens in one third scale were designed, constructed, and tested. The proposed retrofitting technique proved to be very effective in improving the behavior of non-ductile beam-column joints, and to change the final mode of failure. The comparison between beam-column joints before and after retrofitting is presented in this study as exhibited by load versus deflection, load versus CFRP strain, energy dissipation, and ductility.

In-vessel tungsten components of a future demonstration fusion reactor are likely to be operated in the material's non-ductile regime. Assessment of the components' reliability is not possible with current ductile design codes or through experimental qualification. There is therefore an urgent need for non-ductile assessment procedures. One such approach currently considered is Weibull's weakest link theory, which is based on linear-elastic fracture mechanics and has its origins in ceramics. A full assessment of its validity has been performed, and the challenge of obtaining irradiated material data addressed. Bend tests at the macroscopic scale confirm previous findings that the scatter in strength of pure tungsten follows a two-parameter Weibull distribution, provided the material fractures within its elastic regime. However, tests conducted over a range of specimen sizes reveal the technique's shortcomings in accurately predicting the material's size effect in fracture, questioning its applicability to pure tungsten and also other brittle metallic materials. Fracture strength tests conducted at the micrometre scale through cantilever bending have addressed the challenge of obtaining irradiated material data. An ultra-fine grained self-passivating tungsten alloy, considered as an alternative contender to tungsten for in-vessel components, is shown to fracture within its linear-elastic regime at the microscopic scale. A reliable and repeatable measurement of its strength of approximately 5.9 GPa is obtained. The scatter in measurements is shown to be greater than random errors, and to be described well by a two-parameter Weibull distribution. Cantilever tests conducted over a range of specimen sizes reveal a strong size effect (4.3 - 9.0 GPa), which is accurately predicted by Weibull's weakest link theory. Ion implantations, conducted in the tungsten alloy to mimic neutron induced elastic collision damage, result in a statistically confirmed drop (6 %) in cantilever measured fracture strength at low doses (0.7 dpa), and an increase (9-16 %) at higher doses (7 dpa).The cantilever test technique is therefore suitable for the measurement of ion and neutron irradiation effects on the material's fracture strength. Provided a full validation of Weibull's weakest link theory strength extrapolation from the micro- to macroscopic scale is realised on a future heterogeneity free material batch, irradiated material data obtained from cantilever tests could be used to assess the reliability of in-vessel components fabricated from a self-passivating tungsten alloy, and fill the current gap in non-ductile design assessment procedures.

Incremental Dynamic Analysis (IDA) procedures are advanced and then applied to a quantitative risk assessment for bridge structures. This is achieved by combining IDA with site-dependent hazard-recurrence relations and damage outcomes. The IDA procedure is also developed as a way to select a critical earthquake motion record for a one-off destructive experiment. Three prototype bridge substructures are designed according to the loading and detailing requirements of New Zealand, Japan and Caltrans codes. From these designs 30 percent reduced scale specimens are constructed as part of an experimental investigation. The Pseudodynamic test is then to control on three specimens using the identified critical earthquake records. The results are presented in a probabilistic riskbased format. The differences in the seismic performance of the three different countries' design codes are examined. Each of these current seismic design codes strive for ductile behaviour of bridge substructures. Seismic response is expected to be resulting damage on structures, which may threaten post-earthquake serviceability. To overcome this major performance shortcoming, the seismic behaviour under bi-directional lateral loading is investigated for a bridge pier designed and constructed in accordance with Damage Avoidance principles. Due to the presence of steel armoured rocking interface at the base, it is demonstrated that damage can be avoided, but due to the lack of hysteresis it is necessary to add some supplemental damping. Experimental results of the armoured rocking pier under bi-directional loading are compared with a companion ductile design specimen.

Ductile braced frames are often used to resist lateral earthquake loads in steel buildings; however the presence of a brace element can sometimes interfere with architectural features. One common type of ductile braced frame system sometimes used to accommodate architectural features is the eccentrically braced frame (EBF). In order to dissipate seismic forces, EBF beam regions (called links) must sustain large inelastic deformations. EBF links with column connections must transmit large moments and shear forces to facilitate link rotation. Experiments have shown that welded link-to-column connections tend to fracture in the link flange prior to large link rotations. This study investigated methods for improving EBF link-to-column connection performance, and proposed an alternative ductile braced frame system for accommodating architectural features. Several EBF links with reduced web and flange sections were analytically investigated using validated finite element models in ABAQUS. Results indicated that putting holes in the link web reduced stress and strain values in the link flanges at the connection, but increased the plastic strain and stress triaxiality in the web at the edges of holes. Removing area from the link flanges had little effect on connection stresses and strains. Thus, the reduced web section and reduced flange section methods are not a promising solution to the EBF link-to-column connection problem. The alternative braced frame system proposed in the dissertation used ductile beam splices and buckling-restrained braces in eccentric configurations (BRBF-Es) to accommodate architectural features. Design considerations for the BRBF-Es were determined and dynamic BRBF-E performance was compared with EBF performance. BRBF-E system and component performance was determined using multiple finite element methods. Inter-story drifts and residual drifts for the BRBF-Es were similar to those for EBFs. Results indicated that BRBF-Es are a viable alternative to the EBF, and may result in better design economy than EBFs. With the BRBF-E, damage was isolated within the brace, and in the EBF, damage was isolated within the link, indicating simpler repairs with the BRBF-E. Shop welding of BRBF-E members may replace the multiple field welds required in EBF construction.

The aim of the thesis is design and technological design of wing with significant reduction manual work and number of preparations in preparing part of structures. The first part of the work is to explanation the issues and machining metal parts forming wings and also the use of CAD systems. The next section describes several design proposals wings, strength test and compare price and weight of main girders with breams made of L-profiles. Followed by the technological process of production individual part design and control hems of sheet metal part design. The conclusion is dedicated to building assembler wings.

The Advisory Council of Aeronautical Research in Europe (ACARE) has set record emission reduction targets for 2020, in response to increased awareness of global warming issues and the forecast high level of growth in global air traffic. In order to meet this legislation engine designers have to consider new and unconventional designs. An intercooled aero-engine with a heat exchanger (HX) positioned between the IP and HP compressors has the potential to reduce emissions and/or reduce specific fuel consumption relative to conventional engine cycles. In such an engine a coolant delivery system is required to bleed a proportion of the bypass flow, from behind the fan outlet guide vane (FOGV), rapidly diffuse the flow (to reduce pressure loss through the HX modules) and present it to the intercooler (i.e. heat exchanger) modules for cooling. This spent cooling air is then fed back into the bypass duct. To realise the benefits of the intercooled cycle the coolant delivery system must diffuse the flow, within the geometrical constraints, with minimal pressure loss and present it to the heat exchanger modules with suitable flow characteristics over a range of operating conditions. Therefore, a predominately experimental study, complemented with CFD predictions, was undertaken to investigate the design and performance of a coolant delivery system aimed at providing high pressure recovery in a relatively short length. For this to be achieved some pre-diffusion of the flow is required upstream of the offtake (i.e. by making the offtake larger than the captured streamtube), with a controlled diffuser or hybrid diffuser arrangement located downstream of the offtake. Although targeted at an intercooled aero-engine the concept of a system that produces a high pressure recovery in a limited length is applicable to a variety of applications. Experimental data were obtained on a modified existing low speed isothermal annular test facility operating at nominally atmospheric conditions. The offtake must operate aft of the FOGV in a highly complex flow field environment. Hence, a 1½ stage axial flow compressor (IGV, rotor and modified OGV) was used to simulate the unsteady blade wakes, secondary flows, loss cores and other turbo-machinery features that can significantly influence offtake performance. Preliminary numerical (CFD) studies enabled an offtake configuration to be determined and provided understanding of the governing fluid mechanic processes. A relatively small scale, low speed test facility was designed that had the capability to evaluate aerodynamic processes in isolation (i.e. pre-diffusion, controlled diffusion, hybrid diffusion) and full system modelling to enable the complex interaction between these flow processes to be assessed. Hence an optimal system could be characterised in terms of total pressure loss, static pressure recovery and flow profiles at HX inlet. Measurements and numerical predictions are initially presented for a baseline configuration with no offtake present. This enabled the OGV near field region to be characterised and provided a datum, relative to which the effects of introducing an offtake could be assessed. The results showed that in the near field region (i.e. within one chord downstream of the FOGV) the high velocity gradients in the circumferential direction, and associated turbulent shear stresses, dominate the profile mixing and loss production. There is little mixing out of profiles in the radial direction. Furthermore, the relatively large amount of kinetic energy associated with the compressor efflux and its subsequent mixing to a more uniform profile (i.e. reduced blockage) results in a significant static pressure recovery (Cp=5.5%). With the offtake present a variety of configurations were investigated including different levels of pre-diffusion, prior to the offtake, and different offtake positions. This enabled evaluation of the upstream pressure effects and interaction with the upstream FOGV. For very compact systems of short length, such that the gap between the OGV and offtake is relatively small, the amount of pre-diffusion achievable is limited by the offtake pressure field and its impact on the upstream OGV row. This pressure field is also influenced by parameters such as the non-dimensional offtake height and splitter thickness. For systems of increased length a significant amount of flow pre-diffusion can be achieved with little performance penalty (relative to the datum configuration). Hence, the loss associated with mixing blade wakes and secondary flows in an adverse pressure gradient is relatively small. However, the pre-diffusion level is eventually limited, to approximately 1.5, by the increased distortion and pressure losses associated with the captured streamtube. Further measurements were made with various controlled diffuser and hybrid diffusers (of varying area ratio) downstream of the offtake and various levels of pre-diffusion. The flow profile that is presented to the controlled diffuser is directly influenced by the upstream pre-diffusion process. Hence, in this case the upstream-downstream interaction is relatively strong. Conversely, the downstream-upstream interaction, between the controlled diffuser and pre-diffusion process, is relatively weak and thus has little effect on the upstream flow field. The data enabled an optimal system to be characterised (pre-diffusion/controlled diffusion split) in terms of total pressure loss, static pressure recovery and flow profiles at HX inlet. A total system diffusion of 1.8 was achievable with a pre-diffusion of 1.4 and controlled diffusion of 1.25, with further increases in either the pre-diffusion level or the controlled diffuser area ratio destabilising the system. This was achieved with an absolute mass weighted total pressure loss of 11% measured from FOGV inlet to the controlled diffuser exit plane. Utilising a hybrid bled diffuser, combined with the pre-diffusion, enabled a total system diffusion of 2.24 to be achieved. The system incorporated a 6% bleed from the hybrid diffuser and a system total pressure loss of 13%. Experimental and computational results obtained in the current research have provided an understanding of the governing flow mechanisms and quantified the geometric and aerodynamic interaction of the offtake with the FOGV and between the diffusion processes. This has enabled a design methodology to be outlined that provides approximate information on system geometry and performance (in terms of optimal diffusion split and total pressure loss) for future coolant delivery systems with minimal effort. Preliminary design maps have been developed to define the magnitude of the interaction between the offtake and FOGV in terms of the offtake height, pre-diffusion level, the splitter thickness and the axial distance between the fan OGV and offtake. In this way systems of optimal diffusion split, minimum pressure loss and minimal axial length can be determined.

O adenocarcinoma pancreático (PDAC) é uma neoplasia de difícil diagnóstico precoce e cujo tratamento não tem apresentado avanços expressivos desde a última década. As tecnologias de sequenciamento de nova geração (next generation sequencing - NGS) podem trazer importantes avanços para a busca de novos marcadores para diagnóstico de PDACs, podendo também contribuir para o desenvolvimento de terapias individualizadas. Bancos de dados são ferramentas poderosas para integração, padronização e armazenamento de grandes volumes de informação. O objetivo do presente estudo foi modelar e implementar um banco de dados relacional (CaRDIGAn - Cancer Relational Database for Integration and Genomic Analysis) que integra dados disponíveis publicamente, provenientes de experimentos de NGS de amostras de diferentes tipos histopatológicos de PDAC, com dados gerados por nosso grupo no IQ-USP, facilitando a comparação entre os mesmos. A funcionalidade do CaRDIGAn foi demonstrada através da recuperação de dados clínicos e dados de expressão gênica de pacientes a partir de listas de genes candidatos, associados com mutação no oncogene KRAS ou diferencialmente expressos em tumores identificados em dados de RNAseq gerados em nosso grupo. Os dados recuperados foram utilizados para a análise de curvas de sobrevida que resultou na identificação de 11 genes com potencial prognóstico no câncer de pâncreas, ilustrando o potencial da ferramenta para facilitar a análise, organização e priorização de novos alvos biomarcadores para o diagnóstico molecular do PDAC.
Pancreatic Ductal Adenocarcinoma (PDAC) is a type of cancer difficult to diagnose early on and treatment has not improved over the last decade. Next Generation Sequencing (NGS) technology may contribute to discover new biomarkers, develop diagnose strategies and personalised therapy applications. Databases are powerfull tools for data integration, normalization and storage of large data volumes. The main objective of this study was the design and implementation of a relational database to integrate publicly available data of NGS experiments of PDAC pacients with data generated in by our group at IQ-USP, alowing comparisson between both data sources. The database was called CaRDIGAn (Cancer Relational Database for Integration and Genomic Analysis) and its funcionalities were tested by retrieving clinical and expression data of public data of genes differencially expressed genes in our samples or genes associated with KRAS mutation. The output of those queries were used to fit survival curves of patients, which led to the identification of 11 genes potencially usefull for PDAC prognosis. Thus, CaRDIGAn is a tool for data storage and analysis, with promissing applications to identification and priorization of new biomarkers for molecular diagnosis in PDAC.

The beam column joints in reinforced concrete frame building is the most critical part of the structure as the time when seismic forces act on the building, A large amount of forces attracted at beam column joints. Mostly, failure of structure is shear failure at joint and it is brittle nature. This type of failure not required as earthquake resistance design. For avoiding shear failure of joints IS Codes and different countries codes also, gives recommendation of beam and column joints in ductile frames that the joints must have adequate shear strength and ductility to facilitate the development of large inelastic reversible rotation in the event at the time of severe earthquake by providing this special confining reinforcement (hoops). This confining reinforcement near the column end should be extended in the join as well. Development length requirement for flexural reinforcement within the joint is also required. It is desirable to use high strength concrete mix in the joint region and shall achieve good compaction of concrete. The main problem at beam column joints is diagonal cracking and crushing of concrete. In the joint resign concrete may controlled by two means by providing large column sizes and closely spaced steel ties around column bar in the joint region. Ties are to hold the joint together and also resist the shear forces thereby reducing the cracking and crushing of concrete. We study Corner (knee) joint with the help of SAP and Staad model as finite Element Member and note the failure load, moments and deflection for two conditions, opening joint and closing joint. In another model we increased the area of concrete by providing 45 degree angle in the concrete fillet and provide nominal reinforcement. It is found that the moment, axial force and deflection are reduced. In third model, we increased concrete area by providing two fillet surfaces and again found moment, axial force and deflection are reduced. Fourth specimen same as third specimen, but we have provided extra reinforcement at tension side of opening joints. We have also verified experimentally by making four types of specimen and tested in the lab and found same results.

碩士
國立臺灣科技大學
營建工程技術學系
83
Steel structures are widely used in the construction of buildings in Taiwan. The strength and ductility of steel buildings depend greatly on the behavior of their beam-to- column connections. However, from past studies, it is found that about 20% of the connection specimens failed brittle. The fracture of beam-to-column connection of steel frames in Northridge earthquake also arose concerns about the reliability of the current design and construction practice. This reported research is part of a series research work deal with the enhancement of ductility of steel beam-to-column connections. The suggested connection method is able to achieve a plastic rotational angle about two times larger than that is generally required where the strength of the new design can be 1.2 times higher than that of the nominal values. The design guideline for this reliable ductile connection are also presented in this

碩士
國立臺灣大學
機械工程學研究所
102
Ductile cast irons have been widely applied in the industry due to their high strength and ductility. In view of the stringent quality requirements for the castings, not only the mechanical properties must meet the specification, but also the shrinkage defects should be prevented. In this study a high strength grade (FCD-800-2) ductile cast iron was chosen as the target alloy, and a heavy section ductile iron casting (120mm cube) was selected for the study of the optimal riser design. Regarding the riser design, top risers were employed in this study. The experimental results indicate that under the condition of 1400oC pouring temperature, the optimal riser design obtained is：Dr=70mm, Hr=70mm, Dn=40mm, Hn=20mm. On the other hand, as the insulated riser sleeve or exothermic riser sleeve was used, the optimal riser designs for both types are：Dr=54mm, Hr=54mm, Dn=40mm, Hn=20mm. Accordingly, a reduction of riser size (volume) as high as 55% can be obtained when insulated or exothermic riser sleeves were employed. Regarding the alloy design and heat treatment that are required to meet the FCD-800-2 specification, the C and Si contents are set at 3.6% and 2.4%, respectively. Moreover, in order to attain a merely fully pearlitic matrix, Fe-Mn alloy and copper (Cu) were added. 25mm-Y blocks were cast for tensile specimens. The experimental results show that the optimal alloy design is 0.2%Mn, 1.0%Cu, with the as-cast mechanical properties of 797MPa, 500MPa, 6.3% and 290HB for tensile strength, yield strength, elongation and hardness, respectively. Furthermore, as the optimal heat treatment condition of 890oC-1hr/oil quench at 600oC-1hr/furnace cooling to RT was conducted on the specimens, the following mechanical properties: 864MPa in tensile strength, 720MPa in yield strength and 4.5% in elongation can be obtained, all meeting the FCD-800-2 specification.

碩士
國立聯合大學
材料科學工程學系碩士班
106
In the feeder design for ductile iron casting, not only the hotspot regions resulting from its geometry should be considered, but also fluid flow behavior deriving from the spherical graphite formation in liquid-solid region during solidification. In this region, the spherical eutectic structure of the spherical graphite shelled by Austenite results in increasing apparent viscosity of liquid cast iron, and some volumetric expansion of spherical graphite also happens due to its low density relative to that of the iron phase. In this study, First Principe model, the numerical solidification model, was used to simulate the complex solidification process of ductile cast iron liquid. This model includes the residual liquid region (or hot-spot) tracking scheme in 3-dimension during solidification, and it also considers the fluid-flow behavior and the volumetric expansion of the spherical graphite crystallized from the liquid iron. This model was validated by casting a cube-shaped cast. Outlines and locations of porosities in the cross-sectional area of the castings with feeders were confirmed by the hardness contours. In the single-hotspot-cube cast without feeder, a conical shaped shrinkage piping was found on its top and the volumetric percentage of porosity over to the whole cast is 3.9% in the modeling result. From this result, the bulk density of the cast in the modeling is close relative to that of real casting measured by the Archimedes method. In the feeder shape experiments, the optimized feeder shape is cylindrical feeder with a neck connected to the cast. In this feeder shape with the optimized dimensions, the solidification modulus ratios of feeder over cast is 1.07. Its feeding efficiency is averaged value of 12.31% in this single-hotspot-cube cast. In the feeder neck experiment, the solidification modulus ratio of the whole feeder over the cast is the minimum (e.g., 1.056 at 1450°C) if that of the neck over the cast is closed to 1.0. At the temperature lower than 1400°C, the modulus ratio of the feeder over the cast is over than 1.1, while that is less than 1.1 at temperature greater than 1450°C. In the temperature range from 1350°C to 1450°C, that modulus ratio of the neck over the cast is in the minimum of 0.55. In double-hotspot-cube cast, the two hotspot could be considered as one hotspot cast, if the modulus ratio of its bridge over its two cube shapes is greater than the critical value of 0.86. In that case, the modulus ratio of the feeder over the whole cast is in the range between 1.12 and 1.16. Thus, the averaged feeding efficiency is 17.81%. Using this feeding rule, an optimized feeder volume of 226899mm3 was calculated for a real ductile iron cast example, the break caliper cast. In this feeder design, shrinkage porosity located just awaythe cast was successfully achieved. It is a proof that two hotspot behavior in this real ductile iron cast with the correctness of its feeding efficiency rule.

碩士
逢甲大學
機械與電腦輔助工程學系
104
The purpose of this study is to investigate the design of ductile cast iron pot spout and the treatment and mechanism of surface oxidation layer. The design of pot spout includes height of spout, spout inlet and outlet area ratio. The relations between surface color, metallographic microstructure and heat treatment conditions of ductile cast iron surface oxidation layer also are discussed. The result of experiment show that the spout height of ductile cast iron pot should be designed to zero that is parallel to the top of the total height of pot body. More suitable design for the spout inlet area and the spout outlet area ratio, there are two ways. The first is that when spout inlet area is 10% of the central cross section area of the spot body, and spout outlet area is 10% of spout inlet area. The second is that when spout inlet area is 20% of the central cross section area of the pot body, and spout outlet area is 5% of spout inlet area. There are mainly three different results at the heat treatment temperature, that the ductile iron casting surface color is relatively difference, there are 573 K, 873 K, 1173 K. Ductile iron specimens surface color is blue-black after the heat treatment temperature of 573 K, the reddish brown color after the 873 K and the deeper blue after the 1173 K. After analyzing, the Hematite (Fe2O3) and Magnetite (Fe3O4) iron oxide simultaneously appear on the surface of specimen with the heat treatment temperature of 873 K. The Hematite (Fe2O3) iron oxide only appears on the surface of specimen with the heat treatment temperature of 1173 K. The ductile cast iron specimens have generated considerable oxide thickness after the heat treatment temperature of 1173 K. When heat treatment temperature of 873 K, the metallographic structure of ductile cast iron specimens increase in ferritic area ratio and decrease in pearlite area ratio. When heat treatment temperature of 1173 K, the metallographic structure of ductile cast iron specimens increase in pearlite area ratio and decrease in ferritic area ratio. For the graphite nodule counts and the nodular graphite diameters of ductile cast iron, the trends are falling down when increasing the heat treatment temperature. The nodularity of ductile cast iron specimens are not affected by the heat treatment temperature. The heat treatment temperature of 1173 K is the more appropriate for the ductile cast iron oxidation layer forming after comprehensive survey.

碩士
逢甲大學
機械工程學所
95
The objective of this research is to focus on the manufacturing of furan resin mold ductile cast iron by using the In-mold Process. The effect of inoculation treatment used reaction chamber design (position, inlet to outlet cross section area ratio, inoculant and reaction chamber height ratio, shape etc.,) and casting parameters (addition amount and grain size of inoculant, pouring temperature etc.,) on the mechanical properties (tensile property, toughness, hardness, etc.,) and metallographic microstructures (nodularity, nodule count, matrix etc.,) of the ductile cast iron will be investigated in this research. The results of this study indicate in two ways： A. In the reaction chamber design of In-mold Process inoculation treatment： (1)When the inoculation treatment used reaction chamber position from the nodulation treatment used reaction chamber position is 60 mm, the mechanical properties are the best. The nodularity is 93%, the nodule counts are 320 counts/mm2, the tensile strength is 406MPa. (2)When the reaction chamber inlet and outlet cross section area ratio is 1：1, the casting quality of the ductile cast iron casting is the best. The nodularity is 92%, the nodule counts is 302 counts/mm2, the tensile strength is 476MPa, and the elongation is 23%. (3)When the inoculant to the reaction chamber height ratio is 3/4, the nodularity and the tensile strength of casting are better than the other two height ratios. The nodularity is 92% and the tensile strength is 436MPa. (4)When the shape of the reaction chamber is designed as a cubic, the nodularity(93%) and the tensile strength(456MPa) are the best. Either the modulus increased (cylindric) or decreased (rectangular), the metallographic microstructure and the mechanical properties were toward to worse. B. In the casting parameters： (1)When the addition amount of inoculant is 0.3%, the tensile strength and the ductile are better. The results of tensile strength and ductility variation are matched with the metallographic microstructure results of nodularity and matrix. (2)When the grain size of inoculant is coarse ( 3.62~2.42mm), the metallographic microstructure and tensile strength are the best for the ductile iron casting. (3)When pouring temperature is 1500℃, the metallographic microstructure and tensile strength are better for the ductile iron casting. (4)Use and with finer filter ( 1.5mm) to make inclusion content reduce, and the metallographic microstructures and mechanical properties will be improved to some extent. So it is good to propose using the filter and with finer filter ( 1.5mm). SEM-EDS analyses show that oxide and carbide are major compositions of the inclusion in ductile iron casting. (5)Use the statistic method of coefficient of variation to analyze the repeatability of casting quality, the results show the coefficient of variation is smaller than 5%. So it can be concluded that the repeatability of casting quality with optimum inoculation treatment used reaction chamber design condition is good. (6)When the nodularity, nodule count, diameter of graphite, ferrite content of the ductile cast iron with inoculation obviously improved, also increase the ductility, toughness and reduce the hardness. SEM analyses show that Inoculation treatment can thin pearlite structures and increase ferritic grains. All these can be proved from the improvement of mechanical properties.