53 Physik
Refine
Year of publication
Document Type
- Conference Proceeding (63)
- Contribution to a Periodical (22)
- Article (peer reviewed) (3)
- Part of a Book (3)
- Doctoral Thesis (2)
- Report (2)
- Other (1)
- Working Paper (1)
Is part of the Bibliography
- no (97)
Keywords
- Holzdecken (10)
- Schallschutz (10)
- Altbausanierung (7)
- Holzbalkendecken (7)
- Schalldämmung (6)
- Finiten Elemente Methode (5)
- Trittschalldämmung (5)
- Lightweight buildings (4)
- Holzbau (3)
- Körperschall (3)
- Lightweight floors (3)
- Timber joist floor (3)
- Vibroakustik (3)
- Active Learning (2)
- Building acustics (2)
- Doppelhäuser (2)
- Energieeffizienz (2)
- Flipped Classroom (2)
- Force Concept Inventory (2)
- Gebäudetrennwand (2)
- Holzmassivbau (2)
- Holzwände (2)
- Just in Time Teaching (2)
- Multi-Storey Buildings (2)
- Sanierung (2)
- Schalldämpfung (2)
- Trittschallberechnung (2)
- Trockenbau (2)
- Tutorials in Introductory Physics (2)
- Wärmepumpen (2)
- aktivierende Lehre (2)
- Academic Development (1)
- Active Learning Spaces (1)
- Approximation Theory (1)
- Artificial Intelligence (1)
- Artificial Intelligence and Teaching (1)
- Aspect ratio (1)
- Attenuation (1)
- Außendämmung (1)
- Bauakustik (1)
- Bauteilkatalog (1)
- BlackBox (1)
- Blended Learning (1)
- Blended learning (1)
- Bolzentreppe (1)
- Boundary conditions (1)
- Concepts& Principles (1)
- Conceptual Change (1)
- Conceptual Understanding (1)
- Conservation (1)
- Contact Structure-Borne Sound Sources in Buildings (1)
- Cross Reality Laboratories (1)
- Cyclopropane (1)
- Dachdeckung (1)
- Double-leaf timber-frame wall (1)
- Dämpfung (1)
- EN 12354 (1)
- Electric excitation (1)
- Estimates of mobility (1)
- Fassadenverkleidung (1)
- Fehlkonzepte (1)
- Finite Element Methode (1)
- Finite element method (1)
- Force- and moment mobilities (1)
- Frequencies (1)
- Functions (1)
- Gas-Absorption (1)
- Großraumbüro (1)
- HVAC (1)
- Heat pump (1)
- Higher Education Pedagogy (1)
- Holz-Leicht-Bau (1)
- Holzhäuser (1)
- Holzständerwände (1)
- Home retrofit (1)
- Hybrid Lectures (1)
- Impulse-Momentum (1)
- Instructional materials development (1)
- Instructional strategies (1)
- Item Response Curves (1)
- Joist floors (1)
- Just-in-Time-Teaching (1)
- Kompressionskältemaschine (1)
- Konzepttest (1)
- Körperschallquellen (1)
- Learning space (1)
- Massivholzbau (1)
- Massivholzelemente (1)
- Materialeigenschaften (1)
- Metall-Feder-Profile (1)
- Metalldämmung (1)
- Microcontroller (1)
- Neubau (1)
- Novice Teachers (1)
- Nur-Strom-Gebäude (1)
- Peer Instruction (1)
- Physical Thinking (1)
- Physics Education Research (1)
- Physics Education research (1)
- Physics Labs (1)
- Physics Methods (1)
- Physics Teaching in Engineering Education (1)
- Point and transfer mobility (1)
- Point mobility (1)
- Power transmission (1)
- Quality Teaching (1)
- Quantum Mechanics (1)
- R-22/R-142b Mixture (1)
- R22/R152a Mixtures (1)
- Radiation (1)
- RaumImRaum (1)
- Raumakustik (1)
- Refrigeration (1)
- SEA Berechnung (1)
- SEA based prediction (1)
- Schallemissionen (1)
- Schalloptimierung (1)
- Schallschirm (1)
- Scholarship of Teaching and Learning (1)
- Single Equivalent Approximation (1)
- Single equivalent receiver (1)
- Single-Evaporator Domestic Refrigerators (1)
- Single-Evaporator Refrigerators (1)
- SoTL (1)
- Sound measurement (1)
- Sound tramsmission (1)
- Sound transmission (1)
- Sound trasmissions (1)
- Spatial variation (1)
- Steildächer (1)
- Structure-born power (1)
- Structure-born sound (1)
- Structure-born sound power (1)
- Structure-born sound transmission (1)
- Structure-borne sound propagation (1)
- Strömungsmechanik (1)
- Substitute for R-12 (1)
- Substitutes for R12 (1)
- Tapping Machine (1)
- Teacher Education (1)
- Teaching Physics (1)
- Thermodynamics (1)
- Timber joist floors (1)
- Trenndecken (1)
- Trittschallmessung (1)
- Ultra-Concurrent Labs (1)
- Verlustfaktor (1)
- Vibration sources (1)
- Vibro-acoustic sources (1)
- Vibro-acoustical design (1)
- Wärme-Kälte-Kopplung (1)
- Wärmedämmung (1)
- absorption circuit (1)
- activating methods (1)
- aktivierende Lehre, moderne Didaktik (1)
- blended learning (1)
- concept assessment (1)
- diversification (1)
- energetisches Monitoring (1)
- examination (1)
- fault detection (1)
- flexibility (1)
- flexible education (1)
- groupwork (1)
- hands-on experiments (1)
- hands-on learning (1)
- hybrid lecture (1)
- integrierter Absorptionskreis (1)
- learning success (1)
- lithography skills (1)
- maschine learning (1)
- measurement technology (1)
- microtechnology competence (1)
- multimedia (1)
- occupancy (1)
- online lectures (1)
- open textbooks (1)
- physics curriculum (1)
- physics learning (1)
- physics teaching (1)
- point-connected ribbed plates (1)
- random forest (1)
- residual analysis (1)
- rib-stiffened plates (1)
- ribbed structures (1)
- ribbed-plate structures (1)
- scientific method (1)
- semiconductor industry (1)
- single equivalent exitation (1)
- single equivalent mobilities (1)
- teaching methods (1)
- test development (1)
- video (1)
A "hybrid" team-based physics course was developed and rolled out at the Albstadt-Sigmaringen University, Germany, with the intention to provide more flexibility in space and time for the students. Data on the correlation between type of participation and learning success showed, that participation in person together with the performance in other STEM related courses are the main predictors for learning success. Interestingly, it had no influence on the learning success of the non-participating students whether they participated remotely or not at all. Thus, the biggest challenge for the lecture of the future, which offers more flexibility in space and time, is the "activation" of students who participate remotely.
A written exam in measurement technologies usually includes problems for operational amplifier circuits, error propagation, signal analysis and analog to digital conversion. During corona, teaching changed from presence lectures to remote lectures and examination formats changed, too. Instead of a written exam, student project exams were proposed. The projects included a computer aided temperature measurement with operational amplifier circuits, a calibration procedure, error propagation and a written report. The student project exams were successful and the students’ feedback was so positive that the student project exams are going to be continued.
In Tampere UAS the physics and mathematics education will be organized in a new way. The new model increases flexibility for students to choose a learning method suitable for them. The new model also offers some strong support for those students that are at the greatest risk to underperform or drop out their studies. The flexibility includes a possibility for an asynchronous online implementation in every physics and mathematics course. The stronger support means some extra workshop lessons for those who are in danger of dropping out. These workshop lessons concentrate on the very basics of the subject matter.
This paper delves into the impact of artificial intelligence (AI) on learning and teaching engineering physics, focusing on the use of AI chatbots. The study explores various issues encountered by educators when students utilize AI to solve physics problems, highlighting potential pitfalls and opportunities. Through testing AI chatbots' capabilities in physics learning, the paper evaluates their effectiveness in providing accurate and insightful responses. Results indicate that while AI, especially ChatGPT 4, shows promise in aiding students' understanding of physics concepts, there are limitations and challenges to consider, such as over-reliance on technology and the potential for AI to produce misleading solutions. The implications and discussions underscore the need for a balanced approach in integrating AI into education, emphasizing authentic understanding over merely obtaining correct answers. Using AI in creating teaching materials is not evaluated here.
This paper describes the transformation of engineering physics education through activating teaching methods for better learning outcomes and the redesign of learning spaces to support these pedagogical approaches. The transformation of a traditional physics laboratory into a versatile group work and multipurpose space known as the “STEM-Center,” at Tampere University of Applied Sciences is presented. The transformation was inspired by active pedagogical methods such as "Peer Instruction," "PDEODE," and the "SCALE-UP" method and its associated spaces. After the transformation, the space remains suitable for physics laboratory work. Across all courses, it encourages students to be active participants rather than passive listeners, which in turn improves learning outcomes. Most students express high satisfaction with the pedagogical methods and the learning environment as well as a preference for these engaging and activating methods over traditional lecture-based teaching, highlighting an enhanced learning experience and a stronger sense of ownership over their learning.
The Quantum Mechanics Venue is a learning teaching laboratory for high school students at TU Dortmund University. In this context the lab is continuously used and developed by university students. The lab itself focusses on conducting key experiments in quantum mechanics and the visualization of quantum mechanical effects. By exploiting the contradiction between classical expectation and experimental observation, cognitive dissonances are stimulated and later resolved, which leads to an increased learning outcome. Conducting existing experiments is, however, in some cases hindered by a complicated alignment, which does not aid the quantum mechanical understanding. The desired learning outcome can thus not be achieved in all cases.
In order to address these challenges and to allow for a future remote use of the laboratory, three pilot experiments were transformed into cross reality labs. This allows to decouple the students’ learning experience from the location of the lab. This paper provides an overview over the digitized experiments and gives an outlook on the future of the learning teaching laboratory.
The lecture Basic Principles in Physics is a compulsory subject in the education of primary school teachers at TU Dortmund University and actively attended by 100 to 150 students. Previously the lecture was held as a classic lecture utilizing mainly power point slides and experimental demonstrations. For the winter term 23/24 the lecture format was shifted towards a more interactive format, aiming at specific physics problems to be solved as part of the lecture. In order to free up the necessary time in the lecture itself , the conveyance of knowledge was shifted to the students’ preparation for the individual lectures, by providing texts and videos, which were aided by a short quiz. The lectures as well as the preparation were accessed over the entire semester. This paper provides an overview over the results obtained from the assessments and the final exams, as well as the lessons learned.
Lithography is the workhorse for the global semiconductor industry. At the Applied Physics department of our institute, we have developed course-based projects in which we train physics students lithography skills that are valuable for a career in Europe’s growing semiconductor industry. In this article, I will present the lithography facility at our institute, where students develop lithography processes for the fabrication of microstructures. I will show two examples of lithography projects that provided students the opportunity to grow towards competent, skillful lithographers. I will stress that universities of applied sciences in Europe need microtechnology facilities and competence centres that are embedded in Europe’s semiconductor ecosystem to power the workforce for its industry growth.
Physics lectures for engineering students are often given in a canonical order and using a traditional lecture format which might not always be the best choice. In this article we present a restructured curriculum that focuses on the understanding of oscillations and waves and enriches lectures with hands-on experiments and tutorials.
Research on the teaching and learning of physics has identified specific conceptual and reasoning difficulties that often prevent students from developing a functional understanding of various topics taught in introductory physics courses. There is evidence that instructional materials that take into account such difficulties and prompt students to critically assess their own understanding can improve student learning. In this paper Tutorials in Introductory Physics are introduced, a set of materials intended to supplement the lecture, textbook, and laboratory of standard introductory physics courses for students in physics, engineering, and other fields. The Tutorials in Introductory Physics were originally developed by Lillian McDermott and the Physics Education Group at the University of Washington. They have been translated into other languages, including Spanish, Greek and German. In addition, they have served (and continue to serve) as a model for the development of instructional materials for other STEM subjects, such as electric circuits and engineering mechanics. We discuss various aspects of incorporating the Tutorials into a typical course and possible issues associated with their implementation.
For many years, a team of physicists at the HTWG Konstanz has been shifting the focus of physics education from teaching “content” to teaching “methods”. An overview is given on the derived state. Several questions are addressed, such as: What are the advantages? Are there constraints and limits? How can a shift be achieved? What are student reactions and how does other teaching staff deal with the new situation.
We present how a teaching unit can be designed to teach the scientific method.
To understand how scientific progress happens, it is necessary to understand the fundamental process by which science generates new knowledge. Teaching the process from observation, hypothesis, prediction, experiment/thought experiment, testing and possibly revising the hypothesis to a theory poses several challenges for the teacher. We will show how we let our students carry out this process themselves in a teaching unit of 1.5 hours.
The benefits of activating teaching methods are promoted by many colleagues and have been proven by numerous studies. Nevertheless, experienced instructors often do not switch to those methods in their teaching, and first-time lecturers start with traditional instead of activating methods. This article is aimed at (future) educators who are thinking about implementing such methods, as well as experienced ones and educational support staff who wish to provide support for their colleagues. This report is based on personal experience, (free-response) evaluations, standardized tests, and literature. It shows, which factors supported the introduction of and transformation to activating teaching methods, which made it difficult, and which would have been helpful. It is demonstrated why a changeover is worthwhile for physics educators despite possible risks and setbacks.
Herein we outline the design and construction of an instructional laboratory demonstration of the conservation of linear momentum, by way of the Impulse-Momentum Theorem, utilizing small, commercially available accelerometers attached to microcontrollers. The set-up is equipped with small, OLED screens which are able to display real-time acceleration graphs. Furthermore, a template for an experiment involving this set-up is provided. We also explore various data analysis options for different levels of student sophistication.
Electricity and Magnetism is a 1st-year course for about 250 students in the initial stages of the BSc in Applied Physics at TU Delft. For this subject, we created an open, interactive textbook consisting of short videos with descriptive texts and python calculations as illustrations. In this article, we describe how we arrived at this textbook, what its content is and how we now use it in our teaching.
The Proceedings of the 12th PTEE conference 2024 in Rosenheim present 15 articles from a wide range of actual topics in physics teaching – from artificial intelligence, innovative teaching and examination methods, lab experiments, tutorials to thoughts on what would be desirable to know, when you start teaching (activating) physics.
Das Force Concept Inventory ist ein international etabliertes Diagnoseinstrument für das Konzeptverständnis der Newtonschen Mechanik. Wir haben über einen Zeitraum von zehn Jahren von knapp 5000 Studierenden der Ingenieurwissenschaften an der TH Rosenheim zu Studienbeginn Testdaten erhoben. Die Auswertung mittels Item Response Curves erlaubt für jede Frage die Analyse sowohl der richtigen als auch aller falschen Antwortoptionen. Insbesondere lassen sich auf diese Weise Distraktoren identifizieren, die gängige Fehlvorstellungen widerspiegeln. Es zeigt sich, dass die am häufigsten gewählten Distraktoren auf der Annahme beruhen, jeder Bewegung müsse eine Kraft in Bewegungsrichtung zu Grunde liegen. Daten von Universitäten der USA zeigen ein vergleichbares Ergebnis. Die vorgestellte Analyse dient als Grundlage zur Verbesserung von Lehrsequenzen.
Neue Erkenntnisse aus der Lehr- und Lernforschung und die Möglichkeiten der Digitalisierung bringen neue und spannende Anregungen für die Lehre. In den vergangenen Semestern mussten pandemiebedingt plötzlich ganze Lehrveranstaltungen in ein digitales Format überführt werden. Hinzu kamen sowohl technische als auch didaktische Herausforderungen.
Solche Veränderungen auf einmal umzusetzen, kostet viel Zeit und Energie und ist häufig nicht möglich. Einfacher ist es, in kleinen Schritten eine Lehrveranstaltung zu verändern und so den Lernerfolg der Studierenden zu steigern. Dies kann mithilfe von wenigen Elementen mit teilweise nur geringem Aufwand erreicht werden.
In diesem Beitrag beschreibt der Autor mehrere dieser Elemente, die zum Gelingen einer Lehrveranstaltung beitragen können und die er in den vergangenen Semestern in seinen Lehrveranstaltungen zur Physik für Ingenieure erfolgreich umgesetzt hat.
Just-in-Time-Teaching ist eine Lehrmethode, bei der ein
Teil des Wissenserwerbs in Vorbereitung einer Lehrveranstaltung
vorausgeht. Online-Tests offenbaren hierbei
den aktuellen Lernstand und regen die kritische Auseinandersetzung
mit Fachthemen und dem eigenen Studierverhalten
an. Die Ergebnisse dieser Tests erlauben
es, den Unterricht auf die Bedürfnisse der Studierenden
dynamisch anzupassen und zeitliche Freiräume für weitere
aktivierende Lehrmethoden zu eröffnen.
We report from an ongoing process to develop a thermal conceptual assessment that covers the essential concepts of first-year thermodynamics to be administered to engineering students. The goal is to develop a measurement instrument in order to investigate students’ pre-knowledge as well as the influence of teaching and learning settings. The assessment builds on known misconceptions and concept questions described in the literature. The original items have been modified significantly in the current version 3 of the test in order to create single-choice questions with four distracters each that address frequent misconceptions from student answers in a systematic way. The working process to create these distracters is described exemplarily.
An der TH Rosenheim sind die Lehrenden der Physikgrundlagen für alle technischen Studiengänge in einer Fakultät beheimatet. Das erleichtert und befördert den Austausch nicht nur fachlicher Themen sondern auch didaktischer Fragestellungen. Das zunehmend heterogene Vorwissen der Studierenden sowie die Unzufriedenheit mit studentischen Prüfungsleistungen und eher passiver Unterrichtsbeteiligung gaben den Ausschlag, die Didaktik in den Blick zu nehmen um die Wirksamkeit der Lehre zu erhöhen. Das „Scholarship of Teaching and Learning“ gibt Auskunft darüber, ob das Ergebnis den Aufwand rechtfertigt. Der FCI-Konzepttest zeigt eindeutig die Wirksamkeit der verwendeten aktivierenden Lehrmethoden JiTT und PI. Die Prüfungsergebnisse erweisen sich nicht in gleichem Maße für eine quantitative Analyse als geeignet. Die Auswertung der Daten in Bezug auf Teilnahmeverhalten und Bestehensraten legt den Schluss nahe, dass bei Anwendung studierendenzentrierter und aktivierender Lehrmethoden signifikant mehr Studierende zu einem früheren Zeitpunkt die Klausur erfolgreich ablegen.
We report on an investigation of student thinking about steady-state pipe flow of an incompressible fluid. About 250 undergraduate engineering students were given a test consisting of two hydrodynamics questions, combining multiple-choice format with subsequent open-ended explanations. There is substantial evidence that students have difficulty applying and prioritizing the two basic principles of mass conservation (expressed in the continuity equation) and energy conservation (i.e., Bernoulli’s equation). When faced with questions that involve gravity, dissipative effects (“friction”), or a visible pressure drop, a considerable number of students did not invoke the continuity equation in situations where applying it is a necessary step for arriving at the correct answer. Instead, even after lecture instruction on this topic, many of the first-year students based their answers on ill-supported assumptions about local pressures. Some of them used formal arguments from a simplified Bernoulli equation (“lower pressure means higher velocity”), while others based their answer on intuitive arguments (“higher pressure leads to higher velocity”). We also found reasoning based on analogies to single-particle motion (“flow velocity decreases when flowing upwards or friction is present”). Contrary to other researchers, we did not see any evidence for the hypothesis that students think of water as a compressible fluid. Instead, students’ answers often indicate a lack of understanding of the conservation of mass or its implications for incompressible fluids or of the role that this principle plays in the context of fluid flow. In addition, our data indicate that some students have more general difficulties in describing and reasoning about technical situations, such as applying equations containing multiple variables, distinguishing spatial differences in a quantity from its changes with respect to time, or realizing the meaning of idealizations. We also present some evidence that different levels of activation of students during instruction influence the prevalence of these difficulties and discuss some implications for instruction.
Knowing about the presence and number of people in a room can be of interest for precise control of heating, ventilation and air conditioning. To determine the number and presence of occupants cost-effectively, it is of interest to use already existing air condition sensors (temperature, humidity, CO2) of the building automation system. Different approaches and methods for determining presence have attracted attention in recent years. We propose an occupancy detection method based on a method of supervised machine learning. In an experiment, measurement data were recorded in a research apartment with controllable boundary conditions. The presence of people was simulated by artificial injection of water vapour, CO2 and heat dissipation. The variation of the number of artificial users, the duration of presence and the supply air volume flow of the ventilation resulted in a total of 720 combinations. By using artificial users, the boundary conditions were accurately defined, and different presence situations could be measured time-effectively. The data is evaluated with a method of supervised machine learning called random forest. The statistical model can determine precisely the number of people in over 93% of the cases in a disjoint test sample. The experiments took part in the Rosenheim Technical University of Applied Sciences laboratory.
Faults in Heating, Ventilation and Air Conditioning (HVAC) systems affect the energy efficiency of buildings. To date, there rarely exist methods to detect and diagnose faults during the operation of buildings that are both cost-effective and sufficient accurate. This study presents a method that uses artificial intelligence to automate the detection of faults in HVAC systems. The automated fault detection is based on a residual analysis of the predicted total heating power and the actual total heating power using an algorithm that aims to find an optimal decision rule for the determination of faults. The data for this study was provided by a detailed simulation of a residential case study house. A machine learning model and an ARX model predict the building operation. The model for fault detection is trained on a fault-free data set and then tested with a faulty operation. The algorithm for an optimal decision rule uses various statistical tests of residual properties such as the Sign Test, the Turning Point Test, the Box-Pierce Test and the Bartels-Rank Test. The results show that it is possible to predict faults for both known faults and unknown faults. The challenge is to find the optimal algorithm to determine the best decision rules. In the outlook of this study, further methods are presented that aim to solve this challenge.
Im vom BMWi geförderten Forschungsprojekt Niedrigst-Energie-Hotel wurde ein Bestandsgebäude mithilfe eines umfassenden Sanierungskonzeptes zu einem energiesparenden Nur-Strom-Gebäude entwickelt. Eine höchst wärmegedämmte Hülle, komplett neue Anlagentechnik und intelligente Verknüpfung der Anlagenteile versprechen niedrigen Energiebedarf bei gleichzeitig hohem Komfort.
Doch mit steigender Komplexität der Anlagen steigt auch das Risiko, dass Bestandteile nicht optimal zusammenarbeiten oder sich sogar gegenseitig negativ beeinflussen. Beim energetischen Monitoring werden diese Anlagen und ihre Bestandteile überwacht und deren Energieströme gemessen. Dieses Wissen erlaubt schließlich die detaillierte Bewertung des innovativen Energiekonzepts in der Anwendung und in gewissem Umfang auch die Optimierung der Anlagen.
Zur Auswertung der umfangreichen Datensätze wird das am Karlsruher Institut für Technologie (Fachgebiet Bauphysik & Technischer Ausbau) entwickelte Werkzeug MoniSoft verwendet. Durch die plattformunabhängige Software werden das Monitoring und die Betriebsanalyse vereinfacht. Seit 2013 wird die Software an der Hochschule Rosenheim maßgeblich mit weiterentwickelt.
Projektziele - Durch das energetische Monitoring können folgende Ziele erreicht werden:
Beurteilung des Betriebs der komplexen Gebäudetechnik unter realen Bedingungen, Vergleich der Messergebnisse mit den Erwartungen der Planer, Erarbeitung von Optimierungsmöglichkeiten in der Gebäudetechnik
Die DIN 4109 regelt die Anforderungen an den Schallschutz in Gebäuden sowie den Nachweis der Einhaltung dieser Anforderungen. Im Juli 2016 erschien die komplett überarbeitete und neu strukturierte „neue“ DIN 4109. Im Vortrag werden wesentliche Änderungen, die neuen Rechenverfahren und die relevanten Bauteilkataloge kurz erläutert. Änderungen, die sich speziell für die schalltechnische Planung und Ausführung des Trockenbaus ergeben, werden anhand von praktischen Beispielen aufgezeigt. Damit soll ein Gefühl für Möglichkeiten und Grenzen in der Anwendung der neuen Norm vermittelt werden.
With the increasing mechanization of buildings, it is necessary to be able to predict both the structure-borne sound power input from building machinery and the subsequent propagation of structure-borne sound in the building. This paper considers lightweight constructions and describes the results of an experimental study in the laboratory on a T-junction that was constructed from a timber joist floor and two double leaf timber-frame walls. The focus in this paper is on the vibrational behaviour of one of the timber-frame walls. To assess the vibration pattern and the propagation of structure-borne sound, the surface velocity levels were measured on a grid on both leaves of the wall with point force excitation on one side. This grid allowed calculation of structural intensity vectors. The influence of elements such as the timber studs and tongue and grooved joints between the boards were apparent in different frequency regions. Experimental modal analysis was carried out using measurements on both leaves of the wall, giving information about the coupling in different frequency regions. The results give insight into how such a timber-frame wall could be modelled using statistical energy analysis.
Vor dem Hintergrund des Klimawandels ist die Nachhaltigkeit von Wohngebäuden von enormer Bedeutung für die Gesellschaft des 21sten Jahrhunderts. Niedrigenergie-und Passivhauskonzepte können entscheidend dazu beitragen, den Energieverbrauch in Deutschland maßgeblich zu reduzieren. Diese Konzepte erfordern neue Bauweisen und energieeffiziente gebäudetechnische Anlagen, insbesondere Heizungsanlagen, Wärmepumpen und Lüftungsanlagen. Zusätzlich zur Energieeffizienz wird aber bei modernen Gebäuden ein hoher Wohn- und Arbeitskomfort gefordert und geschuldet. Diesbezüglich ist der bauliche Schallschutz zu einem wesentlichen Qualitätskriterium von Wohngebäuden geworden. Der beim Betrieb von gebäudetechnischen Anlagen erzeugte Lärm wird zunehmend als Problem wahrgenommen, das die Wohnqualität, das Wohlbefinden und damit verbunden die Gesundheit negativ beeinträchtigen kann. Durch die permanente Lärmbelästigung am Arbeitsplatz, durch Verkehr etc. ist die Erholung von Lärmeinwirkungen im eigenen Wohnbereich unerlässlich und lässt der Nachhaltigkeit des
baulichen Schallschutzes eine große Bedeutung zukommen. Dieser kann momentan aufgrund fehlender Planungswerkzeuge für die von gebäudetechnischen Anlagen ausgehenden Schallimmissionen nicht gewährleistet werden. Im Rahmen eines aktuellen, kooperativen Forschungsvorhabens der Hochschule Rosenheim und der Hochschule
für Technik Stuttgart soll dieser Missstand beseitigt werden,indem aufeinander abgestimmte Mess-und Prognoseverfahren für die Körperschallerzeugung und Schallübertragung gebäudetechnischer Anlagen im Massivbau sowie im Holz- und Leichtbau erarbeitet, validiert und Anwendern bereitgestellt werden. Damit soll ein vollständiges Instrumentarium geschaffen werden, mit dem die Geräusche gebäudetechnischer Anlagen unter besonderer Berücksichtigung ihrer Körperschalleigenschaften von der Quelle über die Übertragung im Gebäude bis zum Einwirkungsort geschlossen beschrieben werden können. Die Methoden sollen den Anlagenhersteller für die Charakterisierung der Schallquellen und deren schalltechnische Optimierung zur Verfügung stehen und sollen von den Gebäudeplanern als Prognoseinstrument für die schalltechnische Planung und Auslegung genutzt werden können. Dies ist ausgesprochen anspruchsvoll, da gebäudetechnische Anlagen in vielen Fällen vor allem Körperschallquellen darstellen, deren physikalische Beschreibung aufgrund von Wechselwirkungen zwischen Quellen und Empfangsstrukturen ungleich komplizierter ist als die von Luftschallquellen. So ist die Körperschallerzeugung und -übertragung im Massivbau bekanntermaßen völlig unterschiedlich gegenüber den im Holzbau vorliegenden Bedingungen. Dies erfordert eine separate Betrachtung der Anrege- und Übertragungsmechanismen für beide Gebäudearten und bedingt die Kooperation der HFT-Stuttgart (spezialisiert auf Massivbau) und der HS Rosenheim (spezialisiert auf Holz und Leichtbau). Durch die Beteiligung von Unternehmen aus der gewerblichen Wirtschaft wird zudem sichergestellt, dass die aktuellen Bedingungen des Bauwesens Berücksichtigung finden und die praktische Umsetzbarkeit der Lösungen gewährleistet ist.
Single equivalent approximation for multiple contact structure-borne sound sources in buildings
(2012)
The work reported in the paper addresses structure-borne sound transmission between multiple contact sources and non homogeneous plate receiver structures. This study concentrates on a practical method of predicting the installed structure-borne sound power from mechanical installations in lightweight buildings. The structure-borne sound power is a function of source activity, source mobility and receiver mobility, and all three quantities must be known to some degree. It is rarely practical to consider all transmission paths individually and in detail, and therefore, reduced data sets and less computationally demanding procedures are proposed. The paper examines how source data can be used to assemble single equivalent values, using spatial averages and magnitudes. Single equivalent values of receiver mobility also are proposed for lightweight, point-connected ribbed plate constructions. In case studies, the single equivalent values are used for predicting the structure-borne power in the installed condition.
This paper aims to provide a practical approach to the prediction of structure-borne sound power of mechanical installations in buildings. For structure-borne power, two source quantities, activity and mobility, are required, in combination with one receiver quantity, the receiver mobility. The source activity, in the form of free velocity or blocked force, is usually measured. For source mobility and receiver mobility, estimates, based on simple expressions, can provide a useful starting point. Also, machine bases may be categorised as: compact, plate-like, flanged or framed. Receiver structures, floors and walls, may be categorised as: plate-like, ribbed plate or framed plate. The estimates of source mobility are based on the rigid body value, the characteristic plate mobility and the fundamental plate frequency. For ribbed and framed plate structures, the mobility will vary with location, but again simple estimates of mobility, based on characteristic values and distance from the ribs, are possible.
The work reported in this thesis addresses the problem of structure-borne sound transmission in buildings. Vibrating sources, such as services plant and domestic appliances, transmit vibro-acoustic power, causing noise complaints by occupants in rooms removed from the source room. There is not yet an accepted practical method of predicting the installed power into floors or supporting walls, and thence the resultant sound pressure in rooms.
This study concentrates on the prediction of the installed power from mechanical installations in lightweight buildings composed of framed and ribbed plates. To identify the characteristics of such receiver elements, a field survey has been undertaken, which involved measurement of the point and transfer mobilities of common wall and floor structures. It is shown that the range of measured values of receiver point mobility is surprisingly small and that the constructions investigated often displayed thin plate-like characteristics, with relatively small spatial variations in point mobility. These field measurements give support to the notion of averaging over contacts.
This single equivalent receiver mobility has been assembled both from measured data and from the approximate method and then used in combination with single equivalent source data, to yield an approximate prediction of the installed power. The agreement obtained between the exact and approximate values allowed consideration of a practical implementation of the approximate prediction method, based on a reception plate method which yields the activity and mobility of the tested machine as single equivalent values.
The work reported in this paper addresses the problem of structure-borne sound transmission between vibrating sources and ribbed-plate receiver structures. Vibrating sources, such as pumps, motors, fans, etc., transmit vibro-acoustic power, causing noise complaints by occupants in cars, trains, aircraft, buildings and/or material fatigue and damage. The transmission process is complicated in that sources transmit power through several contacts and by up to six components of excitation at each contact. The structure-borne sound power is a function of source activity, source mobility and receiver mobility, and all three quantities must be known to some degree. For non-homogeneous receiver structures, such as thin-plate cavity constructions or lightweight framed constructions, the sheathing plates are typically fastened to the framing members using bolts, screws or spot-welded joints. Hence the resulting system is a point-connected ribbed plate structure and the receiver mobility is expected to vary significantly with position. Since measured receiver data seldom is available for prediction purposes, a method of estimating the point and transfer mobility of point connected ribbed plates is required. In this paper, an approximate approach, based on substitution forces, is described. The model uses infinite beam and infinite plate behaviour as input quantities. Estimates of point and transfer mobility are compared with measured results using a timber joist floor construction as an example.
In wood framed buildings, floors are formed by fastening wood sheathing to joists spaced at a regular interval. The sheathing is typically fastened to the joist using screws so the resulting system is a complicated periodic point-connected plate-rib structure. It is shown that the point force mobility varies significantly with position. A machine installation generally is close to discontinuities, such as at: floor edges, joist-screw locations, joints between the sheathing plates, and due to workmanship. In such cases, moment excitation might become important at some frequencies and the neglect of moments a priori can ead to inaccurate prediction of the total emission. This paper presents measured point moment mobilities with respect to the distance to discontinuities for a timber joist floor where a single layer of chipboard forms the sheathing. It is shownthat the measured point moment mobility indicates an infinite plate behaviour. This includes for positions above a joist but between screw positions. To determine the relative contribution of moments and perpendicular forces to the total structure-borne sound power, case studies of two sources, a fan unit and a whirlpool bath, are described, for various locations on a timber joist floor.
Single equivalent excitation for the structure-borne power from machines on ribbed-plate structures
(2009)
Machines impart structure-borne power into connected and supporting structures through all contact points and by up to six components of excitation. It is recognised that considering all transmission paths for prediction purposes generally is not a practical approach, due to the large data and computational requirements. Reduced data sets and less computationally demanding procedures are sought which give the total power to the accuracy appropriate for the particular engineering design requirement. In this paper, single equivalent source and receiver values are considered for machines on ribbed-plate structures. In this case, large variations in the structural dynamics at the contact positions can be expected, and spatial averaging will lead to loss of accuracy. Single equivalent values have been assembled from measured source and receiver data. Case studies are described, for a fan unit and a whirlpool bath, on a timber-joist floor, which is a complicated periodic point-connected plate-rib structure. Approximate estimates of structure-borne power are compared with exact values obtained from full mobility matrix formulations. The case studies presented indicate the loss of accuracy of the prediction, which, in many situations, may be sufficiently small to allow such simplifications.
Vibrational active sources introduce structure-borne sound power to the supporting structure through all contact points and by up to six components of excitation. The total structure-borne sound power is a function of source activity, source mobility and receiver mobility and receiver mobility is expected to vary significantly with source position on lightweight structures such as timber joist floors. A case study is presented, in which the spatial variation in structure-borne sound power is examined for a fan unit mounted on a timber joist floor. The exact structure-borne power is obtained from measured source free velocity, and measured source and receiver mobility, where forces are assumed the dominant excitation mechanism. The exact calculations are computationally intensive and require large data sets, and this is generally not a practical approach for prediction purposes. In addition, manufacturers view their products as single entities and desire corresponding single values of source strength. A laboratory reception plate measurement procedure has recently been proposed which yields single equivalent values of source strength and source mobility. This paper investigates if this collapsed data format appropriately describes the dynamic behaviour of the source and especially inhomogeneous receiver structures, to obtain estimates of total structure-borne sound power within acceptable accuracy. Since measured receiver data is usually not available, an approximate method is described, of estimating the point and transfer mobility, based on infinite beam and infinite plate behaviour. The single equivalent receiver mobility then is easily obtained and, when used in combination with single equivalent source data, yields an approximate prediction of the total installed power. Single equivalent estimates of structure-borne sound power are compared with exact values obtained from full mobility formulations. Results indicate that the accuracy of the approximate prediction may be sufficient for such installations.
A practical method is proposed for predicting the total structure-borne sound transmission from machines installed in lightweight buildings. The total structure-borne sound power is a function of the source activity and mobility, and the receiver mobility, at each contact and for each component of excitation. The data and computational requirements for prediction normally are large and are required to be in complex form for the cases where source mobility and receiver mobility are of the same magnitude. This can occur in lightweight framed buildings. However, manufacturers view their products as single entities and desire corresponding single values of source strength. They also desire simple measurement methods
and the data obtained to be in octave or one-third octaves. A laboratory reception plate measurement procedure has been proposed which yields single equivalent values of source strength and source mobility. The source data, in combination with an estimate of the single equivalent value of receiver mobility, yields a simple prediction of the total installed power. The accuracy of the simple prediction depends on the spatial variation in contact conditions. For example, the receiver mobility over a joist is likely to be significantly lower than for positions between joists. Case studies are described for multiple contact sources on a timber-joist floor where the simple predictions are compared with exact values obtained from a full mobility formulation.
The total structure-borne sound power of an installed machine is a function of the source activity and mobility, and the receiver mobility, at each contact and for each component of excitation. The data and computational requirements for prediction therefore are large. Manufacturers view their products as single entities and desire corresponding single values of source strength. A laboratory reception plate measurement procedure has been proposed which yields single equivalent values of source strength and source mobility. The source data, in combination with an estimate of the single equivalent value of receiver mobility, yields the approximate total installed power. The accuracy of the estimate is dependent on the spatial variation in contact conditions over the connections. In addition, phase information has been lost in the simplification. Case studies are described for multiple contact sources on a non-homogeneous plate (a timber-joist floor) where the approximate estimates of structure-borne power are compared with exact values obtained from full mobility formulations.
To estimate the structure-borne sound power of vibrational active machines or components two source quantities, corresponding to the source activity and mobility, and one receiver quantity, the mobility, are usually required. A practical, laboratory-based measurement procedure for the characterisation of mechanical installations has recently been proposed, which yields single equivalent values of source strength and source mobility. In order to predict the power in the installed condition, an estimate of the receiver mobility also is required, again, for practical reasons, in the form of a single equivalent value. This paper considers the single equivalent receiver mobilities for lightweight building structures - timber joist floors. The value obtained is in the form of the average magnitude of the effective mobilities over the contact points. A simple prediction method is proposed for point- and transfer mobilities (both are required to yield the effective mobility at each contact) based on infinite beam and infinite plate behaviour. Estimates for point-, transfer- and single equivalent receiver mobilities are discussed and compared with measured data.