Numerical Simulations in Room Acoustics Using Direct Coupling Techniques and Finite Elements


Book Description

This thesis presents a coupling approach for time-harmonic problems in linear room acoustics. Therein the closed acoustic system is subdivided into air, sound source and different boundary components. The sound field of each air component is approximated with the help of modal basis functions and continuous transitions between single components are enabled by enforcing coupling conditions. Coupling to realistic boundary conditions is realized by wavenumber- and frequency-dependent impedance functions for plate-like sound absorbers. Afterwards the solution is computed by minimizing the energy based on Hamilton's Principle. For computing the basis functions and the energies of the components the Spectral Finite Element Method and the adapted Patch Recovery Method are applied. Finally numerical benchmark-simulations show the applications of this coupling approach.










Scientific and Technical Aerospace Reports


Book Description

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.




Building Performance Analysis


Book Description

Explores and brings together the existent body of knowledge on building performance analysis Shortlisted in the CIBSE 2020 Building Performance Awards Building performance is an important yet surprisingly complex concept. This book presents a comprehensive and systematic overview of the subject. It provides a working definition of building performance, and an in-depth discussion of the role building performance plays throughout the building life cycle. The book also explores the perspectives of various stakeholders, the functions of buildings, performance requirements, performance quantification (both predicted and measured), criteria for success, and the challenges of using performance analysis in practice. Building Performance Analysis starts by introducing the subject of building performance: its key terms, definitions, history, and challenges. It then develops a theoretical foundation for the subject, explores the complexity of performance assessment, and the way that performance analysis impacts on actual buildings. In doing so, it attempts to answer the following questions: What is building performance? How can building performance be measured and analyzed? How does the analysis of building performance guide the improvement of buildings? And what can the building domain learn from the way performance is handled in other disciplines? Assembles the current body of knowledge on building performance analysis in one unique resource Offers deep insights into the complexity of using building performance analysis throughout the entire building life cycle, including design, operation and management Contributes an emergent theory of building performance and its analysis Building Performance Analysis will appeal to the building science community, both from industry and academia. It specifically targets advanced students in architectural engineering, building services design, building performance simulation and similar fields who hold an interest in ensuring that buildings meet the needs of their stakeholders.







New Advances in Modal Synthesis of Large Structures: Non-linear Damped and Non-deterministic Cases


Book Description

The modal analysis of the structures appears to be an essential tool to master their dynamic behaviour. Particularly, the modal synthesis methods combined with the updating technics of the Finite Element models lead to the definition of strategies peculiarly efficient. At present, several developments are being carried out in order to spread these procedures to the latest requirements in structural dynamics: Vibro-acoustic . behaviour; Stochastic approach; Non-linear analysis; Introduction of composite materials. The target of the MV2 International Conference was to take stock of the new methods suggested and to assess their effectiveness. The interest in this book is to gather original works that rely on high-level approaches although these works are clearly intended to industrual applications.




Noise/news International


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Physics Briefs


Book Description




The Combined Finite-Discrete Element Method


Book Description

The combined finite discrete element method is a relatively new computational tool aimed at problems involving static and / or dynamic behaviour of systems involving a large number of solid deformable bodies. Such problems include fragmentation using explosives (e.g rock blasting), impacts, demolition (collapsing buildings), blast loads, digging and loading processes, and powder technology. The combined finite-discrete element method - a natural extension of both discrete and finite element methods - allows researchers to model problems involving the deformability of either one solid body, a large number of bodies, or a solid body which fragments (e.g. in rock blasting applications a more or less intact rock mass is transformed into a pile of solid rock fragments of different sizes, which interact with each other). The topic is gaining in importance, and is at the forefront of some of the current efforts in computational modeling of the failure of solids. * Accompanying source codes plus input and output files available on the Internet * Important applications such as mining engineering, rock blasting and petroleum engineering * Includes practical examples of applications areas Essential reading for postgraduates, researchers and software engineers working in mechanical engineering.