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Advanced Telemetry Tracking System for High Dynamic TargetsMinschwaner, Nathan, Leide, Nelson Paiva Oliveira 10 1900 (has links)
ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / A new advanced 2.4 meter telemetry tracking antenna system allows for successful autotracking of high dynamic targets. The system is designed to work at C, S, and L bands. One of these systems at L/S-band was recently implemented and tested in the field. The testing included tracking aircraft during maneuvers such as rolls, spins, and antenna tower fly-by at high rates of speed. This paper examines test results and some of the features of the new system that allow for continuous tracking.
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Modeling and Simulation of High Dynamic Processes for Laminated Composite Materials with Nonlinear CharacteristicsNazarinezhad Giashi, Abolhasan 30 December 2019 (has links)
This work resulted in a simulation platform and a validated numerical framework, which can precisely model the packaging material that are made of complex paperboard composite laminates and predict the material behaviour when it undergo es processing and converting procedures.
Due to their specific advantages such as flexibility, hygiene, cost-effectiveness and environmental compatibility, paperboard composite materials are widely us ed for food and beverage packaging. The packaging materials are made of multi-layer sandwich laminates and mainly consists of several carton plies, a thin aluminium foil and several polyethylene layers. Compared to other conventional composite structures, such as carbon fibre composites, carton-based packages have an extremely thin composite structure with significantly softer material properties.
To obtain a robust and well-formed commercial packaging, many manufacturing processes are usually carried out, for instance creasing, folding or bottom and gable sealing. In addition to the structural and architectural aspects, various technical requirements must b e met regarding functionality, rigidity and robustness of the packaging. During the converting procedures; especially at higher production speeds, unexpected operational flaws might b e observed often for material rupture and inter-layer delamination influencing the quality of a package performance.
Furthermore, to examine the new paperboard material generations and operational developments, it is necessary to characterize and predict materials behaviour and packaging process if higher converting speeds, extended performance and efficiency are demanded. To satisfy the above-mentioned technical requirements, mathematical modelling and simulation methods are an appropriated way to formulate the paperboard material characteristics and analyse converting processes such as creasing and folding.
A series of quasi-static and high-speed tensile tests were carried out to determine the mechanical properties of the highly anisotropic carton material. In addition to the classical tensile test, improved tests were also conducted specifically to measure the shear strength of the paperboard plies. Tests such as the Rigid Block Shear Test (RST) and the Double Notches Shear Test (DNST) were performed to obtain the shear stress curve and maximum shear strength across the paperboard thickness, respectively. Furthermore, the z-directional tensile test (ZDT) was also employed to identify the paperboard interfacial characteristics in terms of traction-separation curves.
A mathematical model based on the finite element method (FEM) has been develop ed and implemented in the commercial ABAQUS software to simulate material behaviour under highly dynamic loads. The simulation model includes both constitutive elasticplastic formulation of packaging composite structure and a description of interlayer interaction and delamination between the composite plies as well. A formulation according to the Hill ´criteria has been used to formulate the anisotropic elastic-plastic behaviour of the material based on its rate-dependent characteristics. The interaction between the paperboard layers and the corresponding delamination during the creasing and folding processes have been implemented using an anisotropic traction separation model in respect to the relative sliding and opening of the adjacent interfaces.
The most important simulation parameters have been comprehensively investigated and optimized regarding the calculation accuracy, simulation costs and efficiency. Subsequently, the obtained numerical results were successfully validated with available experimental data for practical static and dynamic creasing and folding processes.:1. Introduction
2. The State of the Art
2.1 Introduction
2.2 Paperboard and packaging composites manufacturing process
2.3 Paperboard converting process: creasing and folding
2.4 Analyzing of existing models for packaging materials and packaging procedures
2.5 Conclusions
3 Objective and Research Program
3.1 Objective
3.2 Research Program
4 Continuum Mechanics and Modeling of Packaging Process
4.1 Introduction
4.2 Continuum mechanics
4.2.1 Deformation gradient
4.2.2 Finite strain equations
4.2.3 Constitutive model and stress decomposition
4.2.4 Velocity gradient and rate of deformation
4.2.5 Yield criteria
4.2.6 Hardening law and plastic flow 0
4.3 Analytical model for paperboard material characterization
4.3.1 Constitutive equations
4.3.2 Elasticity
4.3.3 In-plane plasticity
4.3.4 Out-of-plane plasticity
4.4 Contact and interfacial formulation
4.4.1 Normal contact analysis
4.4.2 Tangential contact analysis
4.4.3 Interface model
4.5 Conclusions
5 Development of Experimental Methods for Paperboard Material Identification
5.1 Introduction
5.2 Quasi-static tensile test
5.3 Shear and interfacial experiments
5.3.1 Rigid block shear test (RST)
5.3.2 Double notched shear test (DNST)
5.3.3 Z-directional tensile test (ZDT)
5.4 Paperboard dynamic material characterizations
5.4.1 Dynamic test set-up and measurement
5.4.2 Dynamic material calibration and parameter identification
5.5 Conclusions
6 Paperboard Composites Converting Process Experiments and Finite Element
Modeling
6.1 Introduction
6.2 Material and interfacial numerical modeling
6.3 Punching creasing
6.3.1 Punching creasing experiment
6.3.2 Punching creasing FE simulation
6.4 Dynamic creasing
6.4.1 Dynamic creasing experiments
6.4.2 Dynamic creasing simulation
6.5 Folding model
6.5.1 Folding experiment
6.5.2 Folding simulation
6.6 Conclusions
7 Results and Discussion
7.1 Introduction
7.2 FE results and validation
7.2.1 Quasi-static punching creasing process
7.2.2 High speed rotating dynamic creasing process
7.2.3 High speed folding process
7.3 Conclusions
8 Potential Analysis of Material and Process Optimization
8.1 Introduction
8.2 Material optimization
8.2.1 Material continuum characterization
8.2.2 Material interface characterization
8.2.3 Material shear characterization
8.3 Conclusion
9 Summary and Outlook
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Parameters Affecting the Blast Performance of High Strength Fibre Reinforced Concrete BeamsAlgassem, Omar January 2016 (has links)
A limited number of studies have been conducted in the literature in order to investigate the behaviour of high-strength fibre-reinforced concrete (HSFRC) structural components subjected to blast loads. This study summarizes the results of a research program investigating the potential of using steel fibres to improve the blast performance of high-strength reinforced concrete beams. As part of the experimental investigation twenty beams were tested, including nine beams tested under static four-point bending, and eleven beams tested under dynamic blast loads using a shock-tube. Parameters considered in the study include the effect of concrete strength, steel fibres, fibre content, fibre type, longitudinal reinforcement ratio, and presence of shear reinforcement. All beams in the study have identical dimensions, with a cross-section of 125 x 250 mm and length of 2440 mm. To manufacture the specimens, two beams were cast with normal-strength self-consolidate concrete (SCC), with a specified strength of 50 MPa, while the remaining beams were cast with either plain or fibre-reinforced high-strength concrete having a compressive strength which varied between 95-110 MPa. The steel fibre content in the HSFRC beams varied between 0.5 and 1.0%, by volume of concrete. To investigate the effect of reinforcement ratio (ρ), the beams were reinforced with 2-#4 (American size) bars, 2-15M bars or 2-20M bars (ρ = 1.02%, 1.59%, and 2.41%, respectively). The majority of the plain concrete beams had transverse reinforcement which consisted of 6 mm stirrups arranged at a spacing of 100 mm in the shear spans, while most of the HSFRC beams were built without stirrups. The results indicate that all the parameters in this study (reinforcement ratio, presence of stirrups, concrete strength, steel fibres, fibre content and fibre type) affected the static and blast response of the beams, however, the results demonstrate that steel fibres have a more remarkable effect when compared to the other parameters. The provision of fibres is found to improve the blast performance of the HSC beams by increasing shear capacity, reducing maximum and residual mid-span displacements, reducing blast fragments and increasing damage tolerance.
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Deformační člen formulového vozidla / Formula Car Impact AttenuatorRupčík, Jan January 2015 (has links)
The diploma thesis deals with Formula Student Impact Attenuator design of TU Brno Racing team. The aim of the thesis is the design, the dynamic tests and the production of Impact Attenuator of racing formulas called Dragon 4 and Dragon 5, so to meet the Formula Student rules. The thesis deals further with FEM dynamic analysis of Impact Attenuator.
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Test data generation based on binary search for class-level testingBeydeda, Sami, Gruhn, Volker 08 November 2018 (has links)
One of the important tasks during software testing is the generation of appropriate test data. Various techniques have been proposed to automate this task. The techniques available, however, often have problems limiting their use. In the case of dynamic test data generation techniques, a frequent problem is that a large number of iterations might be necessary to obtain test data. This article proposes a novel technique for automated test data generation based on binary search. Binary search conducts searching tasks in logarithmic time, as long as its assumptions are fulfilled. This article shows that these assumptions can also be fulfilled in the case of path-oriented test data generation and presents a technique which can be used to generate test data covering certain paths in class methods.
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Experimental Techniques and Mechanical Behavior of T800/F3900 at Various Strain RatesYang, Peiyu January 2016 (has links)
No description available.
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Strategies for Scalable Symbolic Execution-based Test GenerationKrishnamoorthy, Saparya 02 August 2010 (has links)
With the advent of advanced program analysis and constraint solving techniques, several test generation tools use variants of symbolic execution. Symbolic techniques have been shown to be very effective in path-based test generation; however, they fail to scale to large programs due to the exponential number of paths to be explored. In this thesis, we focus on tackling this path explosion problem and propose search strategies to achieve quick branch coverage under symbolic execution, while exploring only a fraction of paths in the program. We present a reachability-guided strategy that makes use of the reachability graph of the program to explore unvisited portions of the program and a conflict driven backtracking strategy that utilizes conflict analysis to perform nonchronological backtracking. We also propose error-directed search strategies, that are aimed at catching bugs in the program faster, by targeting those parts of the program where bugs are likely to be found or those that are hard to reach. We present experimental evidence that these strategies can significantly reduce the search space and improve the speed of test generation for programs. / Master of Science
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Avaliação da Aderência em Estruturas Tubulares Metálicas Revestidas com Material Cimentício sob Esforços estáticos e dinâmicos. / Evaluation of bond in structures tubular metal coated with cementitious material under static and dynamic stressSilva, Elisângela Pereira da 26 March 2010 (has links)
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Previous issue date: 2010-03-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The bond on tubular steel coated with cementitious material, such as oil wells is quite
complex. These are subject to change in temperature, pumping, steam injection, vibration
caused by explosive charges, which can harm the interface of the tube cement paste
through the loss of bond. Pullout tests in the laboratory are used for verification of the
bond. However, this technique does not contemplate the life of the structural integrity of
the well. This work aimed to contribute to the improvement of the technical verification of
the bond through static and dynamic loading. For this, first using pullout tests has been
proposed a study to test an improved speed of application loading. For this we used tubes
coated partially of cement paste. Simulating the two contact conditions: no treatment on
the surface of the tubes, and treatment with NaCl. It was observed that the presence of
NaCl and a slower rate of load application positively influenced the bond stress. For the
quasi-static dynamic test, by counting the number of cycles, it was felt that this substance
in the interface showed a greater number of cycles. Thus it was concluded that this
technique is feasible to evaluate the useful life of the well oil. / A aderência em estruturas tubulares metálicas revestidas com material cimentício, tais
como, poço de petróleo é bastante complexa. Estes estão sujeitos a variação de
temperatura, bombeamento, injeção de vapor, vibrações provocadas por cargas explosivas,
que podem vir a prejudicar a interface do conjunto tubo-pasta de cimento, através da perda
da aderência. Ensaios de arrancamento em laboratório são utilizados para verificação desta
aderência. No entanto, esta técnica não contempla a vida útil da integridade estrutural do
poço. O presente trabalho tem como objetivo contribuir para o aperfeiçoamento da técnica
de verificação da aderência através de carregamento estático e dinâmico. Para isto,
utilizou-se primeiro testes de arrancamento para verificação de uma melhor velocidade de
aplicação de carga. Para isto utilizou-se tubos metálicos revestidos parcialmente por pasta
de cimento. Simulou-se duas condições de contato: sem tratamento na superfície dos tubos,
e com tratamento NaCl. Observou-se que a presença do NaCl e uma menor velocidade de
aplicação de carga influenciaram de forma positiva a tensão de aderência. Para o ensaio
dinâmico quase estático, através da contagem do número de ciclos, percebeu-se que a
presença desta substância na interface apresentou um maior número de ciclos. Desta forma
concluiu-se que esta técnica é viável para avaliação da vida útil do poço de petróleo.
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Avaliação da rigidez à flexão de toras de madeira por meio de vibração transversal / Evaluation of bending stiffness of wood logs by means of transverse vibrationCarreira, Marcelo Rodrigo 12 March 2012 (has links)
Antes de utilizar as toras de madeira como elemento estrutural é necessário avaliar as propriedades mecânicas desse material tanto por inspeção visual quanto por ensaio mecânico. A técnica de vibração transversal tem se destacado entre os demais métodos de Avaliação Não-Destrutiva para madeira serrada por obter estimativas acuradas do módulo de elasticidade à flexão. Contudo, testes prévios com essa técnica evidenciaram dificuldades de empregá-la na avaliação a rigidez à flexão de toras. O objetivo deste trabalho foi propor um método de ensaio para estimar o módulo de elasticidade na flexão de toras de madeira por meio de vibração transversal. O método proposto foi testado e validado em uma amostra de 40 toras de Eucalyptus sp. Foram obtidas boas correlações entre o módulo de elasticidade estático e o módulo de elasticidade dinâmico obtido pelo ensaio de vibração transversal. / Before using the wood logs as a structural element is necessary to evaluate the mechanical properties of this material by visual inspection and mechanical testing. The transverse vibration technique has stood out among the other methods of Non-Destructive Evaluation for lumber to obtain accurate estimates of the bending modulus of elasticity. However, previous tests showed difficulties with this technique to use it to evaluate the bending stiffness of logs. The aim of this work is to propose a test method to estimate the bending modulus of elasticity of wood logs by means of transverse vibration. The proposed method was tested and validated on a sample of 40 logs of Eucalyptus sp. It was obtained good correlation between the static bending and dynamic modulus of elasticity obtained by transverse vibration test.
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Ultrastructural Aspects of Pulp Fibers as Studied by Dynamic FT-IR SpectroscopyÅkerholm, Margaretha January 2003 (has links)
Dynamic (or 2D) FT-IR spectroscopy in combination withpolarized IR irradiation has been used in this work to studywood polymer orientation and interactions on theultrastructural level in wood fibers in the native state aswell as the effects of different pulping processes. The woodpolymer interactions were studied under both dry and humidconditions. The matrix of lignin and hemicelluloses located between thewell-ordered cellulose fibrils in the wood cell wall of sprucewas here shown to be more highly ordered than has earlier beenrevealed. It was confirmed that glucomannan is orientedparallel to the cellulose fibrils and is highly coupled to it.The lignin was also shown to have a main orientation in thestructure although this is probably not as strong as that ofglucomannan. The orientation of the lignin may derive from thefact that the polysaccharides act as templates during thelignification of the cell wall. This organization implies thatnot only the cellulose but also the lignin and thehemicelluloses have different mechanical properties in thelongitudinal and cross-fiber directions. The ability to gain molecular information on the stresstransfer in polymers with dynamic FT-IR spectroscopy made itpossible to verify experimentally earlier molecularcalculations on the stress transfer within the cellulose chain.It was also possible to show, on the molecular level, thedominant importance of the cellulose fibrils for the stresstransfer in the longitudinal direction of pulp fibers,including lignin-rich mechanical pulp fibers. The glucomannanof softwood fibers was also shown to participate in the stresstransfer in the fiber direction indicating a close associationwith the cellulose, whereas the xylan showed no dynamicresponse. Already under dry conditions, the lignin was shown tohave a more viscoelastic response than the polysaccharidesduring the loading of pulp fibers and it was thus able to moveindependently of the cellulose. The enhanced spectral resolution obtained with dynamic FT-IRspectroscopy made it possible to study the crystalstructure/chain order of cellulose in pulp fibers. Thepossibility of following changes in the relative cellulose Iallomorph composition of pulp fibers was demonstrated for somechemical pulps. Dynamic FT-IR experiments under humid conditions and ofelevated temperatures made it possible to study the softeningof the biopolymers in their native environment. This was alsodemonstrated for some different pulps, and this may be apromising tool for obtaining viscoelastic information on themolecular level in composite systems such as wood fibers. <b>Keywords:</b>cellulose, cooperation, crystallinity, dynamictest, glucomannan, hardwood, holocellulose, humidity, infraredspectroscopy, kraft pulp, lignin, mechanical pulp, orientation,polarised light, softwood, strain, sulphite pulp,viscoelasticity, xylan
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