571 research outputs found

    Proceedings of SIRM 2023 - The 15th European Conference on Rotordynamics

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    It was our great honor and pleasure to host the SIRM Conference after 2003 and 2011 for the third time in Darmstadt. Rotordynamics covers a huge variety of different applications and challenges which are all in the scope of this conference. The conference was opened with a keynote lecture given by Rainer Nordmann, one of the three founders of SIRM “Schwingungen in rotierenden Maschinen”. In total 53 papers passed our strict review process and were presented. This impressively shows that rotordynamics is relevant as ever. These contributions cover a very wide spectrum of session topics: fluid bearings and seals; air foil bearings; magnetic bearings; rotor blade interaction; rotor fluid interactions; unbalance and balancing; vibrations in turbomachines; vibration control; instability; electrical machines; monitoring, identification and diagnosis; advanced numerical tools and nonlinearities as well as general rotordynamics. The international character of the conference has been significantly enhanced by the Scientific Board since the 14th SIRM resulting on one hand in an expanded Scientific Committee which meanwhile consists of 31 members from 13 different European countries and on the other hand in the new name “European Conference on Rotordynamics”. This new international profile has also been emphasized by participants of the 15th SIRM coming from 17 different countries out of three continents. We experienced a vital discussion and dialogue between industry and academia at the conference where roughly one third of the papers were presented by industry and two thirds by academia being an excellent basis to follow a bidirectional transfer what we call xchange at Technical University of Darmstadt. At this point we also want to give our special thanks to the eleven industry sponsors for their great support of the conference. On behalf of the Darmstadt Local Committee I welcome you to read the papers of the 15th SIRM giving you further insight into the topics and presentations

    Modeling and simulation of surface generation in manufacturing

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    The paper describes the state-of-the-art in modeling and simulation of surface texture and topography generation at micro and nano dimensional scales. Three main classes of manufacturing processes used for the generation of engineering surfaces are considered: material removal processes, material conservative processes, and material additive processes. Types of modeling techniques for the simulation of surface generation are reviewed and discussed including analytical models, numerical multi-physics models, and data-driven methods. After presenting the application of those modeling techniques for the prediction of characteristics and geometry of surfaces generated by different manufacturing processes, their performance, implementation, and accuracy are discussed. Finally, a roadmap for the realization of a complete surface generation digital twin in manufacturing is outlined

    Optical and ultrasound local contact measurements of dry friction interface under vibration

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    Friction joints are widely used in machine design to allow an easy assembly of different components. The joints have the added benefit of providing damping to the structure due to frictional energy dissipation at the interface, which can reduce vibration amplitude and hence improve performance and life of the machine. The nonlinear nature of a friction joint can introduce a significant challenge when predicting the dynamic response of the system and the lifetime of the parts. The prediction of the global dynamic response is relatively accurate today due to the development of different contact models and advance nonlinear solvers, but predicting and measuring the local contact condition inside the joints accurately still represents a major challenge. The latter is of highest importance when trying to accurately represent a joint for accurate nonlinear dynamic predictions, and when trying to predict wear inside the interface. The main aim of this PhD project is to develop approaches that allow the monitoring of the contact interface of friction joints during a vibration cycle and improve the understanding of the contact mechanics at the interface. Initially a comparison of full-field optical measurements and ultrasound measurements on transparent PMMA specimens is used to obtain understanding of the link between the contact mechanics at the interface and the ultrasound signal. A clear link between the optically measured real area of contact and the sliding conditions could be established, which is then linked to the ultrasound signal. This understanding is then used for the interpretation of the ultrasound signal of steel specimens. The ultrasound technique shows the capability to identify sticking, microslip and gross slip stages in one sliding cycle in a steel to steel contact, providing for the first time high quality validation of the local contact condition for explicit nonlinear dynamic models.Open Acces

    Principles and approaches for the machining simulation of ceramic matrix composites at microscale: a review and outlook

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    Ceramic Matrix Composites (CMC) are advanced materials composed of ceramic fibers embedded in a ceramic matrix, resulting in a highly durable and lightweight composite structure offering exceptional high-temperature performance, excellent mechanical properties, and superior resistance to wear and corrosion. CMC find applications in industries such as aerospace, automotive, energy, and defense, where high strength and thermal stability are crucial. Despite their numerous advantages, machining CMC presents unique challenges. The hardness and brittleness of ceramics make them difficult to machine using conventional methods. The abrasive nature of ceramic particles can rapidly wear down cutting tools, leading to decreased tool life and increased costs. Numeric simulations for the machining of CMC are therefore particularly interesting due to their ability to provide insights into tool-material interactions and optimize machining parameters without the need for expensive and time-consuming physical trials. This paper discusses existing methods and approaches from different materials like Carbon Fiber Reinforced Plastics (CFRP) and monolithic ceramics and puts forward an outlook for the numerical simulation of the machining process of CMC

    Micro/Nano Structures and Systems

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    Micro/Nano Structures and Systems: Analysis, Design, Manufacturing, and Reliability is a comprehensive guide that explores the various aspects of micro- and nanostructures and systems. From analysis and design to manufacturing and reliability, this reprint provides a thorough understanding of the latest methods and techniques used in the field. With an emphasis on modern computational and analytical methods and their integration with experimental techniques, this reprint is an invaluable resource for researchers and engineers working in the field of micro- and nanosystems, including micromachines, additive manufacturing at the microscale, micro/nano-electromechanical systems, and more. Written by leading experts in the field, this reprint offers a complete understanding of the physical and mechanical behavior of micro- and nanostructures, making it an essential reference for professionals in this field
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