Statybinių konstrukcijų jungčių įtaka vibracijų silpimui ; Influence of junctions on vibration attenuation,in building construction

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Marius MICKAITIS INFLUENCE OF JUNCTIONS ON VIBRATION ATTENUATION, IN BUILDING CONSTRUCTION Summary of Doctoral Dissertation Technological Sciences, Civil Engineering (02T) 1197 Vilnius 2005 VILNIUS GEDIMINAS TECHNICAL UNIVERSITY Marius MICKAITIS INFLUENCE OF JUNCTIONS ON VIBRATION ATTENUATION, IN BUILDING CONSTRUCTION Summary of Doctoral Dissertation Technological Sciences, Civil Engineering (02T) Vilnius 2005 Doctoral dissertation was prepared at Vilnius Gediminas Technical University in 2001 – 2005. Scientific Supervisor Prof Dr Habil Vytautas Jonas STAUSKIS (Vilnius Gediminas Technical University, Technological Sciences, Civil Engineering – 02T). The Dissertation is being defended at the Council of Scientific Field of Civil Engineering at Vilnius Gediminas Technical University: Chairman Prof Dr Habil Juozas ATKOINAS (Vilnius Gediminas Technical University, Technological Sciences, Civil Engineering – 02T).

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• Publié par: vilnius_gediminas_technical_university
• Publié le: 01 janvier 2006
• Nombre de lectures: 21

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        Marius MICKAITIS         INFLUENCE OF JUNCTIONS ON VIBRATION ATTENUATION, IN BUILDING CONSTRUCTION       Summary of Doctoral Dissertation Technological Sciences, Civil Engineering (02T)            

Vilnius

2005

1197

 

VILNIUS GEDIMINAS TECHNICAL UNIVERSITY                   Marius MICKAITIS         INFLUENCE OF JUNCTIONS ON VIBRATION ATTENUATION, IN BUILDING CONSTRUCTION         Summary of Doctoral Dissertation Technological Sciences, Civil Engineering (02T)            

 

Vilnius

2005

 

Doctoral dissertation was prepared at Vilnius Gediminas Technical University in 2001 – 2005.   Scientific Supervisor Prof Dr Habil Vytautas Jonas STAUSKIS (Vilnius Gediminas Technical University, Technological Sciences, Civil Engineering – 02T).   The Dissertation is being defended at the Council of Scientific Field of Civil Engineering at Vilnius Gediminas Technical University: Chairman Prof Dr Habil Juozas ATKO
INAS (Vilnius Gediminas Technical University, Technological Sciences, Civil Engineering – 02T).   Members: Prof Dr Habil   Rimgaudas ABRAITIS University of (Kaunas Technology, Technological Sciences, Materials Engineering – 08T),   Prof Dr Habil   Jonas BAREIŠIS University of Technology, (Kaunas Technological Sciences, Mechanical Engineering – 09T),   Prof Dr Habil Artras KAKLAUSKAS Gediminas Technical (Vilnius University, Technological Sciences, Civil Engineering – 02T),   Prof Dr Habil Gediminas MAR
IUKAITIS Gediminas (Vilnius Technical University, Technological Sciences, Civil Engineering – 02T). Opponents: Assoc Prof Dr Romanas KARKAUSKAS(Vilnius Gediminas Technical University, Technological Sciences, Civil Engineering – 02T), Prof Dr Habil Vytautas STANKEVI
IUS University of (Kaunas Technology, Technological Sciences, Civil Engineering – 02T).   The dissertation will be defended at the public meeting of the Council of Scientific Field of Civil Engineering in the Senate Hall of Vilnius Gediminas Technical University at 2 p.m. on 15 December 2005. Address: Saul
tekio al. 11, LT-10223 Vilnius-40, Lithuania Tel.: [phone]; fax [phone]; e-mail [e-mail]   The summary of the doctoral dissertation was   distributed on 15 November 2005. A copy of the doctoral dissertation is available for review at the Library of Vilnius Gediminas Technical University (Saul
tekio al. 14, Vilnius, Lithuania)   © Marius Mickaitis, 2005

 

 

VILNIAUS GEDIMINO TECHNIKOS UNIVERSITETAS                   Marius MICKAITIS       STATYBINIJI KONSTRUKCJUNG
I   TAKA VIBRACIJSILPIMUI           Daktaro disertacijos santrauka Technologijos mokslai, statybos inžinerija (02T)              

 

Vilnius

2005 

 

Disertacija   rengta   2001   –   2005   metais   Vilniaus   Gedimino   technikos universitete.   Mokslinis vadovas prof. habil. dr. Vytautas Jonas STAUSKIS Gedimino (Vilniaus technikos universitetas, technologijos mokslai, statybos inžinerija – 02T).   Disertacija ginama Vilniaus Gedimino technikos universiteto Statybos inžinerijos mokslo krypties taryboje: Pirmininkas prof. habil. dr. Juozas ATKO
INAS Gedimino technikos (Vilniaus universitetas, technologijos mokslai, statybos inžinerija – 02T). Nariai: prof. habil. dr. Rimgaudas ABRAITIS (Kauno technologijos universitetas, technologijos mokslai, medžiaginžinerija – 08T),   prof. habil. dr. Jonas BAREIŠIS (Kauno technologijos universitetas, technologijos mokslai, mechanikos inžinerija – 09T),   prof. habil. dr. Artras KAKLAUSKAS Gedimino technikos (Vilniaus universitetas, technologijos mokslai, statybos inžinerija – 02T), prof. habil. dr. Gediminas MAR
IUKAITIS (Vilniaus Gedimino technikos universitetas, technologijos mokslai, statybos inžinerija – 02T). Oponentai: doc. dr. Romanas KARKAUSKAS(Vilniaus Gedimino technikos universitetas, technologijos mokslai, statybos inžinerija – 02T),   prof. habil. dr. Vytautas STANKEVI
IUS (Kauno technologijos universitetas, technologijos mokslai, statybos inžinerija – 02T).   Disertacija bus ginama viešame Statybos inžinerijos mokslo krypties tarybos pos
dyje 2005 m. gruodžio 15 d. 14 val. Vilniaus Gedimino technikos universiteto senato pos
džisal
je. Adresas: Saul
tekio al. 11, LT-10223 Vilnius-40, Lietuva. Tel.: [phone]; faksas [phone]; el. paštas [e-mail]   Disertacijos santrauka išsiuntin
ta 2005 m. lapkriio 15 d. Disertacij perži galimar
ti Vilniaus Gedimino technikos universiteto bibliotekoje (Saul
tekio al. 14, Vilnius, Lietuva) VGTU leidyklos „Technika“ 1197 mokslo literatros knyga   © Marius Mickaitis, 2005

 

 

GENERAL CHARACTERISTIC OF THE DISSERTATION   Topicality of the research. Protection from noise is one of the main six Construction Product Directive 89/106/EEC requirements, which a new building must satisfy. This and other requirements for building protection from noise were incorporated into national laws as construction technical regulations, hygienic rules, and other laws. Standards for dwelling-house protection from noise were created more than fifty years ago in many European countries, and were complicated. Therefore, there began in the whole Europe a unification of the design and measurement procedures of building acoustical properties. When Lithuania became a member of European Union, the European laws for protection from noise became mandatory in Lithuania. The investigations performed in many European countries have shown that many buildings, including also some newly built in Lithuania, do not meet the rules of protection from noise. Even when these laws are satisfied, not always the protection from noise is sufficient, because only minimized general requirements for acoustical comfort are given in the standards. The progress of technology increased the quantity of noise sources, both outside and inside of buildings. Typically, noise sources inside buildings are: human speech, footfall, and building equipment. The main outside noise sources are: the operation of equipment, and vehicle/air traffic. The number of motor vehicles has increased several fold in last two decades in Lithuania, and also there is an intensifying of airline traffic. Therefore, environmental noise level in cities increases every year. Noise in working and living places harms more than twenty percent of EU citizens, and heightens the risk of health problems. Fortunately, our society responds to these negative environmental changes and adopts relevant protective laws. Nationwide and internationally accepted standards require architects, engineers, and builders to design and construct buildings with sufficient acoustical comfort. Progress for the noise-reduction in buildings may be achieved by experimental and theoretical investigation. Development of experimental investigations is based on trial-and-error strategy, while development of theoretical investigations is based on creation and improvement of calculation models. Building protection from noise is realized in the designing, constructing, and commissioning stages. Acoustical properties of building are predicted according to series of LST EN 12354 standards. Reduction of direct sound transmission can be achieved through optimal design of placing “quite” rooms remotely from “noisy” rooms, while the reduction of flanking sound transmission is more difficult. Transmission of structure-borne sound in buildings is especially problematic. Vibration propagates at large distance in building construction with poor damping. Main

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attenuation of vibration energy level is at the junctions of building constructions. Practice has shown that flanking sound transmission through the junctions of buildings is frequently a reason for great decrease of airborne sound insulation. Therefore, modeling of vibration attenuation at junctions of building construction is a relevant research object in construction science.   The Research objectherein is vibration attenuation at variousconsidered forms of junctions in building construction. The elements of junctions are described as idealized plates and beams. Vibration attenuation at junctions is evaluated by transmission coefficient or transmission loss. These parameters depend on sound wave properties, geometrical and physical parameters of the particular junction.   The aim and tasks of the work.The aim of this scientific research is to investigate the influence of geometrical and physical parameters on vibration attenuation at corner, tee, façade tee, and cross form junctions of building constructions. To achieve the main research objective, the following issues must be solved:    To explore calculation methods for sound transmission in buildings.    To analyze the practice and applicability of modeling vibration attenuation at building construction, using statistical energy analysis theory.    To create a theoretical vibration attenuation model at plate junctions, and to investigate vibration transmission losses for various form of junctions.    To create a theoretical vibration attenuation model at complex plate- beam junctions, and to investigate vibration transmission losses for various form of junctions.    To investigate the influence of geometrical and physical parameters on vibration attenuation at plate and complex plate-beam junctions.   Methodology of research. The methodology related with influence of junctions in building construction on vibration attenuation is based on statistical energy analysis theory. This analytical research method, extended by classical bending wave approach, leads to determining of vibration attenuation in buildings. In addition, the numerical results for the evaluation of junction geometrical and physical parameters influence on vibration attenuation were invoked. During the preparation of this research, the author referred to scientific and practical publications of both Lithuanian and foreign authors, and to internationally accepted standards.  

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Scientific novelty     for vibration attenuation at asymmetrical plateA calculation model and complex plate-beam junctions has been created.    Simplified equations for the transmission coefficient of asymmetrical cross-form junction with three equal elements has been proposed.    Influence of geometrical and physical parameters on vibration attenuation at asymmetrical plate and complex plate-beam junctions has been investigated.    Vibration attenuation at asymmetrical junctions and at junctions with column could be introduced to the set of the existing ones in a standardized method.   Approbation and publications.The main results of this work were reported at for scientific nationwide and international scientific technical conferences. Six papers were published on the topic of the dissertation and two of them were published in the magazines from the list approved by the Department of science and Higher Education (see p. 15–16).     The scope of the scientific work. thesis consists of general The characteristics, list of notations, introduction, four main chapters, general conclusions, 56 pictures, 2 tables and list of references. The total scope of the dissertation is 106 pages.   THE CONTENT OF THE DISSERTATION   1. Introduction   In the Chapter 1 classification of noise in buildings, features of structure- borne sound transmission and calculation of sound transmission in buildings methods were briefly outlined. Semi-empirical airborne and impact sound insulation between rooms calculation models, described in standardized method LST EN 12354, are used for the evaluation of acoustical parameters in the projecting stage. Another two theoretical methods – Statistical Energy Analysis (SEA) and Finite Element Method (FEM) – are complementary, and both methods have a particular range of applicability.   2. Analysis of Vibration Attenuation Models at Junctions in Building Construction   This chapter presents a survey of the scientific literature related to modeling of sound transmission at joints in building constructions, concentrating on semi-infinite plate joints model based on SEA theory. In a SEA, a model or system is subdivided into separately described subsystems, which are conjoined by boundary conditions. Some of the properties of the SEA model can be written without information about all of the

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physical system. In any system or subsystem is valid an equilibrium, that the ingoing power must equal the leaving power. Therefore, power balance equations may be written, which may be used for the evaluation of different parameters. Energy is the parameter used as the measure of sound and vibration for all subsystem simplifies the calculations (Fig 1). The parameter that determines power flow in the system is the coupling loss factor. Transmission coefficient the main indicator that  isdetermines the coupling loss factor at joints in building constructions.  

  Fig 1.Concept of SEA model from three subsystems   Analyzing the layouts and sections of different buildings, the most part configuration of joint form as symmetric could be noticed. For many years researchers have been investigating the process of sound energy transmission at thesemi-infinite plate joints. One of the originators, Cremer, determined the calculation expressions of transmission coefficient for the bending wave transmission. Kihlman estimated the transmission of longitudinal and transverse waves, although his method is rather complicated and requires much initial data. Other researches developed improvements of the basic theories. Woehle modeled a junction of semi-infinite plates rigidly connected to a beam, which has no mass. Several studies investigated the influence of vibration transmission and wave type conversion in beams. The results of the research can be applied to calculation of vibration transmission from beams to plates. The examination of vibration transmissions through complexplate-beam joints, which are common in framed buildings, is very relevant. The in-line junction where two plates were connected to a column from opposite sides was calculated by Cremeret al. column was modeled as a very thin beam. The Later, the author extended investigations by including moments applied to a column. Craven, Gibbs and others evaluated the column in various L-, T- and X-form joints, where the column resisted forces and moments applied from the connected walls. Evaluating of transverse and longitudinal waves on a vibration attenuation at these joints was performed by Steel.

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The scope of scientific researches in field of building acoustics in Lithuania is quiet poor. Investigations of vibration attenuation at joints in multi- storey residential and public buildings performed by Prof Dr Habil Stauskis V. J. were the one and only. Models for sound transmission throughjoints with elastic layers, acoustically thick plate joints,finite length plate joints,orthotropic plate jointsandpoint connected plate joints which have been based on semi- infinite plate model were also analyzed. Most important and significant results of scientific investigations were presented and the relevance of the research was based.   3. Model of Vibration Attenuation at Plate Junction   This chapter presents a calculation model of vibration attenuation at semi- infinite plate joints based on SEA theory background and equations of classical bending wave theory. Vibration transmission coefficient ij is a ratio of powers, i.e., out-going from the joint and incident on it:  ij P tr /P inc .    (1) Cross-form joint configuration considered in this work is shown in Fig 2. The elements of joint are connected to the beam which has no mass and moment in it is neglected. Bending wave incidents on the joint from the first plate at an angle. Displacementincident wave will be equal to:of this  inc e ik 1 cosx e ik 1 sin 1 y e it . (2)  

    Fig 2.Coordinate system, forces, and deformations for the cross joint 9

 

Reflected to the first element and nearfield bending waves gives the total displacement of the first plate:  1 e ik 1 cos 1 x A 1 e ik 1 cos 1 x A n1 e kn 1 x e ik 1 x e ik 1 sin 1 y e iwt    . (3) Traveling and nearfield waves that leave the joint gives the total displacements in the second, third and fourth plate: cos  sin  2 A 2 e ik 2  2 z A n2 e k n2 z e ik 1  1 y e iwt , (4)  3 A 3 e ik 3 cos 3 x A n3 e k n3 x e ik 1 sin 1 y e iwt , (5)  4 A 4 e ik 4 cos 4 z A n4 e k n4 z e ik 1 sin 1 y e iwt  . (6) Applying the simplest and most commonly used case, it may assume that there are no displacements at the joint. The condition, stating that displacement in the edge (wherex= 0) of the first plate 1 is equal to zero, equation (3) can be simplified to: 1 +A 1 +A n1  (7)= 0 accordingly, from the next condition (wherez= 0), it can be found that: A 2 +A n2  (8)= 0. Similar boundary conditions can be described for the third and fourth plates as: A 3 +A n3  (9)= 0, A 4 +A n4 = 0. (10) In case of the rigid joints, if one of the plates rotates, then the others also must rotate in the same way of the angle, so that the angles between members remain constant, i.e. 90. Power balance is necessary for the sum of moments, which act into the joint element, to be equal to zero. For this reason, rotation of the first and the second plates are 1 = 2 . Expressing the rotations out of displacement condition= / x  presence of (atx 0 and =z = 0) it may be found that:  1 /x 2 /x. (11) By introducingandA n values in equation (11) respectively, the following equations are obtained: A 1 k n1 ik 1 cos 1 A 2 k n2 ik 2 cos 2 k n1 ik 1 cos 1 , (12) A 1 k n1 ik 1 cos 1 A 3 k n3 ik 3 cos 3 k n1 ik 1 cos 1 , (13) A 1 k n1 ik 1 cos 1 A 4 k n4 ik 4 cos 4 k n1 ik 1 cos 1 .   (14) The final equilibrium condition is: the sum of moments, which act into the joint, is equal to zero. This is characterized by the expression: M 1 –M 2 –M 3 +M 4 = 0. (15)

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