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M. Beniušis „Kelto „Victoria Seaways“ šilumokaičio ir aušinimo vamzdyno virpesių tyrimas“. Laivų projektavimo ir statybos magistratūros studijų programos baigiamasis darbas. Darbo vadovas dr. P. Mažeika, Klaipėdos universitetas: Klaipėda, 2014. Raktažodžiai: virpesiai, laivas, keltas, virpesių tyrimai, šilumokaitis. Baigiamojo darbo teorinėje dalyje aprašoma virpesių klasifikacija, pagrindiniai virpesių žadintojai ir analizuojami įvairūs virpesių lygio mažinimo laive, virpesių skaičiavimo būdai. Eksperimentinėje dalyje pateikiama keltų „Victoria Seaways“ ir „Athena Seaways“ aušinimo sistemos dalies virpesių matavimo metodika. Nagrinėjami reiso Klaipėda-Kylis-Klaipėda metu atliktų matavimų rezultatai, bei nustatomos tiriamos aušinimo sistemos dalies padidintų virpesių lygio priežastys. Paskutinėje darbo dalyje pateikiamos išvados ir rekomendacijos. / M. Beniušis “Vibration research of heat exchanger and cooling piping in Victoria Seaways ferry”. Final work of the master studies of ship design and building program. Academic supervisor Dr. P. Mažeika, Klaipeda University: Klaipėda, 2014. Keywords: vibrations, ship, ferry, vibration research, heat exchanger. The theoretical part of the final work describes the classification of vibration, main excitations of vibration and analyses various methods for reduction of the vibration level on board and vibration calculation. The experimental part presents the vibration measurement methodology in the cooling systems of Victoria Seaways and Athena Seaways ferries. It examines the results of measurements carried out during Klaipėda-Kiel-Klaipėda trip and identifies the reasons for the recent level of vibration in the analysed cooling system. The final part of the work contains the conclusions and recommendations.

Title: Detection of rheological changes in the axial system of pregnant women using the TVS method. Objectives: The aim of this thesis is to evaluace the effect of pregnancy on the biomechanical properties of the spine. Methods: TVS vibration diagnostic methods were applied to six pregnant women twice during pregnancy. It was investigated ability of axial system to dampen vibration spreading through out the spine. The ability of every single segment to damp vibrations were compared with each other at the beginning and during pregnancy. Results: TVS method used for purpose of this paper has been proved adequate to provide information about the resonant frequencies and the total attenuation of the spine with sufficient accuracy, so that the biomechanice changes of axial system during pregnancy could be decidly identified. Comparison of the frequency dependency and total attenuation of spine indicated increase of total attenuation of the spine and also increase of flexibility of the spine in all investigated probands. Keywords: gravidity, pregnancy, axial system, vibrations, TVS, spine

Title: Electromyographic analysis of the influence of vibrating dumbbell on upper extremity muscles Objective: The main purpose of this study was to compare the electric activity of m. biceps and triceps brachii, and upper and lower part of m. trapezius, during exercises both with a vibrating dumbbell, and a dumbbell without vibrations. Furthermore, our objective was to compare the muscle activity during static stress (dumbbell kept in one position), and dynamic stress with the vibrating dumbbell (moving in the elbow joint). Methods: Surface electromyography was chosen as an objectification method. Nine healthy women of age between 23 and 26 years participated in this study. A dumbbell of 1, 5 kg weight, 36 Hz vibrating frequency and 1,3 mm amplitude was used. Results: An increase of electrical activity can be observed in all assessed muscles when stimulated with vibrations. However, this increase can be considered as statistically significant only in case of static stress of the m. biceps and triceps brachii. Results also indicate high activity of the upper part of m. trapezius during exercise with activated vibrations. Key words: vibrations, vibrating dumbbell, vibration training, electromyographic analysis

Les systèmes mécaniques soumis et excités par vibrations sont les candidats naturels à être modélisé par des systèmes linéaires invariables dans le temps. La localisation de dommages utilisant les paramètres modaux évalués à partir de données de vibration ambiantes mesurées grâce à de capteurs est possible notamment par l'approche nommée Stochastic Dynamic Damage Location Vector (SDDLV), où l'emplacement des dommages est empiriquement relié aux positions où le stress est proche de zéro. La première contribution dans cette thèse montre comment l'incertitude sur les paramètres du système d'état peut être utilisée pour déduire des bornes d'incertitude sur les résidus de localisation de dommages, ceci afin de décider de l'emplacement de dommage utilisant un test d'hypothèse. Dans la deuxième contribution, la méthode de localisation de dommages est étendue pour être robuste au choix des variables de Laplace utilisées dans cette méthode. Ceci est obtenue en agrégeant statistiquement les résultats à valeurs différentes dans le domaine de Laplace. L'influence Line Damage Location (ILDL) est une approche complémentaire du SDDLV où l'angle entre les sous-espaces principaux est calculé et les dommages sont empiriquement localisés aux points près du zéro. L'approche développée pour la SDDLV est étendue à cette nouvelle approche, l'ILDL. Les méthodes proposées sont validées et appliquées avec succès pour la localisation de dommages dans des structures civiles. / Mechanical systems under vibration excitation are prime candidate for being modeled by linear time invariant systems. Damage localization using both finite element information and modal parameters estimated from ambient vibration data collected from sensors is possible by the Stochastic Dynamic Damage Location Vector (SDDLV) approach, where the damage location is empirically related to positions where the stress is close to zero. The first contribution in this thesis shows how the uncertainty in the estimates of the state space system can be used to derive uncertainty bounds on the damage localization residuals to decide about the damage location with a hypothesis test using one chosen Laplace value. In the second contribution, the damage localization method is extended with a statistical framework and robustness of the localization information is achieved by aggregating results at different values in the Laplace domain. The Influence Line Damage Location (ILDL) is a complementary approach of the SDDLV where the subspace angle is computed and damage is empirically located at points near zero. The last contribution describes how robustness of the localization information is achieved by aggregating results at different values in the Laplace domain based on the previous two contributions. The proposed methods are validated and successfully applied to damage localization of several applications in civil structures.

Increased competition in the capital-intensive paper industry makes optimized operation to an important part of corporate strategies to reduce them overall costs. Running the machines in a reliable way contributes to higher plant availability, which is particularly important in industries where the production rate is high and a break lead to costly production downtime. To achieve high plant availability, an effective maintenance of manufacturing equipment is required. This requires that the right action is taken at the right time. The purpose of this project was to increase understanding of how operation parameters for a paper machine affect the condition of the machine. The condition is assessed by studying the vibration levels using a condition monitoring system installed on the wire section rollers. The goal was to identify tools that can help operators to run the paper machine in a harmless and cost-effective way. The study was conducted by varying three parameters: wire speed, wire tension and vacuum in the suction boxes of the wire section. Wire speed and wire tension were varied for the flat wire and the upper wire. The vacuum was only varied for the flat wire. Each parameter was varied separately and the influence on the rolls vibration levels were analyzed. The range for the different operating parameters was determined in consultation with the operating personnel. There were no clear trends of how the operation parameters affect the machine condition. However, changes in vibration levels for single rolls were found. For the flat wire the changes in vibration levels were small except for a specific roll where the vibration level dropped drastically at increased speed, increased vacuum and higher tension. Even for the upper wire the changes in vibration levels were marginal except for a specific roll, which increased tension resulted in reduced vibration level, -from 2,74mm / s to 1.56 mm / s, which is a significant difference when the alarm limit of the machine is 2.5mm / s. This is an important discovery because the rollers can be seen as vital components in a series of linked systems and their operation is necessary for the paper machine to perform its required function. A conclusion is that relatively small adjustments of operation parameters affect vibration levels, which will have an effect on the component remaining life, and hence the system availability. / Ökad konkurrens inom den kapitalintensiva pappersindustrin gör att en optimerad drift blir en viktig del i företagens strategier för att minska dem totala kostnaderna. Att köra maskinerna på ett driftsäkert sätt bidrar till högre anläggningstillgänglighet, vilket är särskilt viktigt vid industrier där produktionstakten är hög och ett avbrott leder till kostsamma produktionsbortfall. För att uppnå hög anläggningstillgänglighet krävs också ett effektivt underhåll av tillverkningsutrustningen. Detta kräver att rätt åtgärder sätts in i rätt tid. Syftet med detta examensarbete var att öka förståelsen för hur olika driftparametrar för en pappersmaskin påverkar tillståndet för maskinen. Tillståndet bedömdes genom att studera vibrationsnivåer från ett lagerövervakningssystem installerat på virapartiets valsar. Målet var att hitta redskap som kan hjälpa operatörerna att köra pappersmaskinen på ett så skonsamt och kostnadseffektivt sätt som möjligt. Studien genomfördes genom att variera tre driftparametrar: virahastighet, viraspänning och undertryck i virapartiets suglådor. Virahastighet och viraspänning varierades för både planviran och överviran. Undertryck i virapartiets suglådor varierades endast för planviran. Varje parameter varierades separat och parametrarnas påverkan på valsarnas vibrationsnivåer analyserades. Intervallet för de olika driftparametrarna bestämdes i samråd med driftspersonalen. Sett för hela maskinen gick det inte att se några tydliga trender för hur driftparametrarna påverkade tillståndet för maskinen. Däremot kunde man se förändringar i vibrationsnivå för enstaka valsar. För planviran var ändringarna i vibrationsnivåerna marginella undantaget en specifik vals där vibrationsnivån sjönk drastiskt vid ökad hastighet, ökat vacuum samt ökad spänning. Även för överviran var ändringarna i vibrationsnivåer marginella utom för en specifik vals, där ökad spänning gav minskad vibrationsnivå, -från 2,74mm/s till 1,56 mm/s vilket är en betydande skillnad då larmgränsen från maskintillverkaren är 2,5mm/s. Detta är en viktig upptäckt eftersom valsarna kan ses som vitala komponenter i ett seriekopplat system och deras funktion är nödvändig för att pappersmaskinen skall kunna utföra krävd funktion. En slutsats är att det med ganska små justeringar i driftparametrar går att påverka vibrationsnivåerna, som i sin tur påverkar komponenternas livslängd och systemets tillgänglighet.

Master of Science / Department of Architectural Engineering and Construction Science / Bill Zhang / Vibration has been a consideration in many types of structures, and as the advancement of technology has allowed steel and concrete sections to become lighter, vibration has become more of a consideration in the design of structures. This report focuses on occupant induced vibration of steel framed floors due to running as the vibration source. The history of vibration analysis and criteria in structures is discussed. However, lack of research and experimentation on running as the source of vibration exists; therefore, the history section focuses on walking as the source of vibration. The current design criteria for vibration of steel framed floors in the United States of America is the American Institute of Steel Construction (AISC) Design Guide 11: Vibrations of Steel Framed Structural Systems Due to Human Activity. This design guide discusses vibration due to walking, running, and rhythmic activities as well as gives design criteria for sensitive occupancies and sensitive equipment. In order to apply the Design Guide 11 analysis procedure for running as the source of vibration, the Kansas State University Chester E. Peters Recreation Complex is used as a case study. The recreation complex includes a 1/5-mile running track that is supported by a composite steel framed floor. Based on the Design Guide 11 criterion, the running track is deemed acceptable. Lastly, this report discusses remedial procedures in the case of annoying floor vibration specific to floors that have running as a source of vibration. In addition, areas of further research are suggested where running is a source of vibration on steel framed floors.

Since the offshore drilling for oil and gas is venturing into ever greater water depths, drilling risers face problems of vortex-induced vibrations due to the currents. Vortexinduced vibrations are a major fluid load and fatigue component on the long, smooth, and slender bodies placed in a fluid flow and measures must be taken to suppress the shedding of the Karman vortex sheets from its edges. One of the ways to reduce the vibration is to use marine fairings which are attached to the drilling risers with the help of weather vanes. In this thesis, CFD analysis based on solving RANS equations for K-w turbulence model at Reynolds number 10,000 is done for a regular cylinder and one with marine fairing attached. The motivation of such analysis is to compute the efficiency of the fairing arrangement in suppressing the vortex-induced vibrations of the corresponding bluff body.

<p>Thermal dissipation of mechanical energy from periodic loading in energetic materials (EMs) leads to the creation of areas of intense, localized heating, called hot spots. The impact and shock conditions for the hot spot initiation of solid explosives have been extensively explored, but little work has focused on high-frequency contact loading. In order to design formulations to address unintentional initiation by mitigating heating in polymer-bonded explosives (PBXs) and other heterogeneous EMs, the mechanisms of heat generation which lead to the thermal initiation of energetic composites under ultrasonic excitation were explored. Heat generation mechanisms which may lead to unintentional initiation were identified through the diagnostic techniques of second harmonic generation (SHG) of δ-HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocine) crystals; X-ray phase contrast imaging (PCI) performed at the Argonne National Laboratory Advanced Photon Source; infrared (IR) thermography; and optical microscopy. This work concludes with high-speed mesoscale observations of dense layers of PETN (pentaerythritol tetraniterate), CL-20 (hexanitrohexaazaisowurtzitane), RDX (1,3,5-trinitro-1,3,5-triazine), and HMX which were damaged or driven to decomposition under acoustic insult using the non-intrusive imaging technique of shadowgraphy to detect hot spots within the transparent binder. Recommendations are formed which address binder adhesion, energetic material properties, and particle morphology on the vibration sensitivity of a PBX formulation. </p>

Cette thèse commence avec un état de l’art des domaines d’études importants pour notre objectif (différentes techniques usuelles de réduction des vibrations en usinage, méthodes de contrôle actif) avant de valider le principe de contrôle actif du fraisage en se plaçant en repère fixe. On a alors développé un modèle d’état d’une poutre d’Euler Bernoulli perturbée en un point et corrigée en un autre via un actionneur piézoélectrique. Ce modèle a permis d’obtenir plusieurs compensateurs, suivant différentes stratégies de commande. Nous avons par la suite procédé, d’un point de vue expérimental, à l’étude sur un dispositif similaire à notre besoin d’un point de vue de l’actionnement et des ordres de grandeurs (amplification mécanique, gamme de fréquences etc.). Les stratégies de commande robustes que nous avons développé pour pouvoir atténuer les déplacements vibratoires de cette poutre ont conduit à des résultats concluants présentés dans le même chapitre, d’abord en simulation (qui nous a permis une étude comparative), avec ou sans la présence du processus d’usinage, puis expérimentalement. La robustesse de ces stratégies de commande a été étudiée (en simulation) en ajoutant des incertitudes au modèle étudié de différentes manières. Ensuite, nous avons identifié le modèle du système étudié, déterminé les correcteurs correspondants et testé ces derniers sur notre banc d’essai pour valider le bon fonctionnement des différentes stratégies de contrôle utilisées tout le long de cette thèse. Enfin, pour préparer un déploiement de ces stratégies en repère tournant (porte-outil de contrôle actif), nous avons modélisé et implémenté les mêmes démarches pour le cas où l’actionnement se situe en repère tournant et concerne deux axes simultanément, situés dans le plan XY du porte-outil. Nous avons d’abord étudié les vibrations transversales d’une poutre en rotation dans le cas général avant de négliger les phénomènes d’inertie et gyroscopique. En effet, on s’intéresse au contrôle actif du fraisage particulièrement dans les applications de finition, là où on utilise des outils longs de faibles diamètres. Les nouvelles expressions des deux fonctions de transfert de notre système usinant ont été déterminées pour obtenir sa représentation d’état, clé du contrôle actif. La projection du processus de coupe sur le repère tournant est indispensable pour effectuer les simulations du fraisage via le porte outil actif. Ce dernier chapitre met en relief les perspectives de cette thèse, à savoir le contrôle actif du fraisage quelque soit le type de l’opération ou du diamètre de l’outil avec un porte outil mécatronique destiné pour ce genre d’opérations. / This thesis deals with the fields of study which are important for our objective (different usual vibration reduction techniques in machining, active control methods) before validating the principle of active control of milling in a fixed reference. We then developed a state space model of an Euler Bernoulli beam excited at one point and corrected in another one by a piezoelectric actuator. This model allowed us to obtain several compensators, according to different control strategies. We then proceeded from an experimental point of view to study a device similar to our need from an actuating point of view and levels of magnitude (mechanical amplification, frequency range, etc.). ). The robust control strategies that we have developed to attenuate the vibratory displacements of this beam have led to conclusive results presented in the same chapter, first in simulation (which allowed us a comparative study), with and without the cutting process and then experimentally. The robustness of these control strategies was studied (in simulation) by adding uncertainties to the model in different ways. Then we have identified the model of the system, calculated the corresponding compensators and tested them on the test bench in order to validate the good functioning of the different control strategies used in this thesis. Finally, in order to use these strategies in rotating reference (active control tool holder), we have modeled and implemented the same steps for the case where the actuation is located in rotating reference and concerns two axes simultaneously, located in the XY plane of the tool holder. We first studied the transverse vibrations of a rotating beam in the general case before neglecting the inertia and gyroscopic phenomena. Actually, we are interested in the active control of milling, particularly in finishing applications, where long tools of small diameters are used. The new expressions of the two transfer functions of the system have been determined to obtain its state space representation, key of the active control. Projection of the cutting process on the rotating reference is essential to perform milling simulations with the active tool holder. This last chapter highlights the prospects of this thesis,that is the active control of the milling for all kinds of milling operations as well as for different tools with a mechatronic tool holder aimed for this kind of operation.