SEA yöntemi yardımıyla tek ve çift tabakalı yapı elemanlarından ses geçiş kayıplarının hesaplanması için bir bilsayar programı geliştirme

Abstract

Tezin amacı; yapı elemanlarının ve uygulama şekillerinin hava doğuşlu seslere karşı davranış biçimlerinin ve ses iletiminde etkili özelliklerin incelenmesidir. Birinci bölümde; ses iletim kaybı hesaplanmasında kullanılan yöntemler ve bu çalışmada kullanılan SEA yönteminin genel özellikleri anlatılmış, yöntemler arası karşılaştırılma yapılmıştır. İkinci bölümde; klasik akustik ve SEA yöntemlerinde kullanılan, ses iletiminde etkili parametreler ve kavramlardan bahsedilmiş, SEA yöntemi ile ilgili modelleme esasları açıklanmıştır. Üçüncü bölümde; iç hacimlerde, tek tabakalı ve çift tabakalı bölücü ara duvarlardan, hava doğuşlu sesler için ses iletim kaybı hesaplarını yapmak amacıyla kullanılan SEA yöntemi incelenmiştir. Dördüncü bölümde, incelenen SEA hesap yöntemi için akış diagramı oluşturulmuş ve Visual Basic 4.0 derleyicisi kullanılarak bilgisayar programı haline getirilmiştir. Beşinci bölümde, geliştirilen bilgisayar programı kullanılarak tek tabakalı ve çift tabakalı duvarlardan ses iletim hesaplan yapılmıştır. Uygulamalarda; farklı malzemelere ve kalınlıklara sahip esnek ve rijit tespitli tek ve çift tabakalı duvarlardan ses iletimi, çift tabakalı duvarlarda tabakalar arası strüktürel bağların ve boşluk genişliğinin iletimine etkisi incelenmiştir. Yapılan araştırma sonucunda, hava doğuşlu seslere karşı bölücü duvarlar için geliştirilen bilgisayar programı ile çeşitli yapı elemanlarından ses iletim kaybı hesapları yapılmış ve elde edilen veriler doğrultusunda ses yalıtımı konusunda bazi pratik sonuçlar ortaya çıkarılmaya çalışılmıştır.Development in the technology, increased use of new, larger, and more powerful machines everywhere, that causes noise to become an unavoidable by-product of our mechanized life and a serious hazard to our health. All sounds that are distracting, annoying, or harmful to everyday activities (work, rest, entertainment, or study) are regarded as 'noise'. Thus, even speech or music wHI be regarded as noise when they are unwanted Sound can be produced 1. in the air, for example, the human voice or a musical sound, 2. by impact, such as walking, or slamming a door, 3. by machinery vibration. In this research, behaviors of building elements and contruction applications against airborne sounds and effects of the material properties on sound transmission are examined and tried to find out some practical solutions for noise control in buildings. The research contains five chapters; In Chapter 1 ; a general explanation about the prediction methods for airborne sound transmission through building elements and the SEA method which is used in this research is given. A comparision of the methods are made and the advantages and disadventages of the SEA method are tried to explained generally. In Chapter 2; the classical acousics parameters and terms for sound transmision loss, which are also valid in SEA, other terms and parameters that are unique to SEA, and principles of designing an SEA model are described. In section 2.1; the descriptions of sound transmission through xu building elements, the resonance and critical frequencies, the parameters that effect sound trasnmission loss in classical acoustics are given. In section 2.2; the parameters and terms that are unique to SEA method (system, subsystem, sound trasmission mechanism in a SEA method, power flow, power balance equations, energy, total loss factor in a subsystem due to the internal and coupling loss factors and radiation efficiency of a panel), are described. In section 2.3; the principles of modelling a system (due to the subsystem properties, sound wave types and strueture-to-structure couplings) according to the SEA method is given in general. In Chapter 3; the sound transmission mechanisms for interior building elements due to the airborne sound and the prediction of sound transmission loss by SEA method is given. Sound transmission system through a single- leaf wall can be represented schematically by the block diagram shown in Figure 1 and Figure 2. Figure 1. Two rooms seperated by a common wall w3, W, J^~^ W,; %h W" W2: ^h. W,, W3<1 Figure 2. SEA model of two rooms seperated by a common wall. 1- source room, 2- single-leaf wall, 3- recieving room. xm For any subsystem that is in equilibrium, the power going in must equal the power leaving. This leads the power balance equations which are used to determine the overall performance of the system. As it can be seen in Figure 2, there is two transmission paths thorugh the wall, the first path is the resonant transmission path (W12-W23) and the second is the non- resonant transmission path (W13). Due to these transmision paths shown in Figure 2, the power balance equations can be written as; Wt + W21 + W31 = W1d + W12 + W13 W12 + W32 = W2d + W21 + W23 W13 + W23 = Wsd + W3i + W32 Sound transmission system through the cavity walls depending on the types of the wall leaves that can be categorized as double masonry walls, lined masonry walls and lightweight double walls. Different trasmission paths (resonant, non-resonant) and coupling mechanisms (due to the air, or wall ties e.t.c.) are dominant for each type of the cavity walls, depending on the frequency band which lies below and above the transition frequency and critical frequencies. In general sound transmission system through a cavity wall can be represented schematically by the block diagram shown in Figure3. 1 2 Source room O Source ^ Receiving roon & Figure 3. The SEA model of two rooms seperated by a cavity wall. XIV It is assumed that, the two leaves are modelled as separate subsystems. Usually transmission is dominated by transmission across cavity wall ties so that the cavity need to be included as a subsystem. The power balance equations for cavity walls can be written as; Wi = Eı.ö.Tiid E1.co.TH2 = E2.cD.Ti2d Ei.©.Tli3 + E2.CO.TI23 = E3.CO.TI3d E2.CÛ.TI24 + E3.CO.TI34 = E4.C0.Tl4d E3.CÛ.TI35 + E4.CO.TI45 = E3.CO.Tl5d A diagram is developed using SEA method to predict airborne sound transmission through interior building structures and a software is prepared in order to simplify the calculations. In Chapter 4; the capacity of the computer needed to run the programme and the general structure (Figure.4) of the software is explained. -7] Single-leaf Walls r> Double Cavily Walls ^ Double Masonry Walls Masonry Walls with Lining Lightweighted Double Walls \/ Sound Reduction Index, dB /\ Figure 4. General form of the programme. XV In the research; some inputs are taken as constant data (air density, sound speed in the air, internal loss factors of the building materials etc.) and some are variables (source room, receiving room and structure data). In Capter 5; to examine the effects of structural properties in sound transmission loss following applications are made;. the sound reduction index of the wall samples used in the applications are compared,. the effects of wall masses (thickness and surface density) are examined,. the effects of the simply-supported panels are examined,. the effects of the cavity wall ties (for double masonry walls, masonry walls with lining and lightweight double walls) on sound transmission losses are examined,. the effect of cavity absorptivity and the cavity depth are examined. From the obtained applications, following results are observed;. sound trasmission loss increases with increase in the frequency, but arround the critical frequency, the expected increase due to the frequency raise can not be observed,. Increase in the mass (thickness, or density) of the wall increases sound transmission loss,. simply-supported conductions have high transmission losses than rigid- supported constructions,. double walls connecting with cavity wall ties have less sound reduction index compared to air couplings through the cavity,. increase in the stiffness or number of wall ties, increases sound transmisison through the walls,. increase in the cavity depth, incerases the sound reduction index.