A Study on Noise in Synchronous Belt Drives: Experimental and Theoretical Analysis of Impact Sound

2000 ◽  
Author(s):  
Weiming Zhang ◽  
Tomio Koyama
Keyword(s):  
Theoretical Analysis ◽  
Natural Frequency ◽  
Sound Source ◽  
Transverse Vibration ◽  
Sound Field ◽  
Acoustic Energy ◽  
Generation Mechanism ◽  
Belt Drives ◽  
Fundamental Natural Frequency ◽  
The Impact

Abstract There are two kinds of noise in synchronous belt drives. One is steady sound caused by transverse vibration of belt, and another is impact sound radiating from meshing point of belt and pulley. Recently, it has been reported that the impact sound is due to the sound occurring in an air pipe built up between pulley groove and belt because the frequency of impact sound coincides with the fundamental natural frequency of an open ended pipe whose length equals width of the belt. However, this conclusion is obtained experimentally, there has no theoretical analysis provided. In this study, an analysis of the impact sound is provided to prove its generation mechanism and discuss factors that influence the level of sound theoretically. Sound field in an open ended pipe subjected to an impulsive sound source is analyzed. Comparison between experimental and analytical results is carried out. It is concluded that the level of impact sound is in proportion to the width of belt, and the acoustic energy of impact sound is in proportion to the cube of the width of belt.

A Study on Noise in Synchronous Belt Drives (Experimental and Theoretical Analysis of Impact Sound)

2003 ◽  
Vol 125 (4) ◽  
pp. 773-778 ◽  
Author(s):  
Weiming Zhang ◽  
Tomio Koyama
Keyword(s):  
Theoretical Analysis ◽  
Transverse Vibration ◽  
Acoustic Energy ◽  
Generation Mechanism ◽  
The Other ◽  
Belt Drives ◽  
Analytical Results ◽  
Belt Width ◽  
The Impact

There are two kinds of noise in synchronous belt drives. One is steady sound caused by transverse vibration of the belt, and the other is impact sound radiating from the meshing point of the belt and pulley. In this study, a theoretical analysis is provided to prove the generation mechanism of the impact sound and discuss factors that influence the level of sound. Comparison between experimental and analytical results is carried out. It is concluded that the level of impact sound is in proportion to the belt width, and the acoustic energy of impact sound is in proportion to the cube of the belt width.

scholarly journals Estimating the influence of double-sided rounded screens on the acoustic field around a linear sound source

2021 ◽  
Vol 3 (5 (111)) ◽  
pp. 38-46
Author(s):  
Vitalii Didkovskyi ◽  
Vitaly Zaets ◽  
Svetlana Kotenko ◽  
Volodymyr Denysenko ◽  
Yuriy Didenko
Keyword(s):  
Acoustic Field ◽  
Cross Sections ◽  
Sound Source ◽  
Finite Thickness ◽  
Sound Field ◽  
Algebraic Equations ◽  
The Road ◽  
Study Results ◽  
On The Road ◽  
The Impact

This paper reports a study into the acoustic field of transport flow around noise protection screens located on both sides of the sound source. Most research on noise protection involving noise protection screens relates to the assessment of the effectiveness of screens located on one side of the noise source. The influence of the second screen on the effectiveness of the first one has been investigated only experimentally. Therefore, it is a relevant task to assess the mutual impact of the two screens between which the linear sound source is located. A problem was stated in such a way that has made it possible to derive an analytical solution and find a sound field around a linear sound source. In this case, the sound source was limited on both sides by acoustically rigid screens with finite thickness. The screens' cross-sections were shaped as part of a ring with arbitrary angles and the same radius. The problem was solved by the method of partial domains. This method has made it possible to obtain an infinite system of algebraic equations that were solved by the method of reduction. Such an approach to solving a problem allows a given solution to be applied for different cases of the mutual location of screens, source, and territory protected from noise. The study results help estimate a field between the screens, the dependence of increasing sound pressure on the road on the geometric size of the screen and the width of the road. In addition, the solution resulted in the ability to assess the impact of one screen on the efficiency of another in the frequency range of up to 1,000 Hz. It has been shown that the mutual impact of screens could reduce the screen efficiency by 2 times. The study reported here could make it possible to more accurately calculate the levels of the sound field from traffic flows when using noise protection screens, which is often performed in practice when designing new and reconstructing existing highways.

Analysis of the Influence of Sea-Surface Reflection on Locating the Underwater Sound Source

2015 ◽  
Vol 727-728 ◽  
pp. 813-818
Author(s):  
Qi Wei He ◽  
Guo Liang Xu ◽  
Shao Chun Ding ◽  
Zhen Dai
Keyword(s):  
Half Space ◽  
Sound Source ◽  
Near Field ◽  
Sound Field ◽  
Sea Surface ◽  
Underwater Sound ◽  
Underwater Acoustic ◽  
Surface Reflection ◽  
Conventional Technology ◽  
The Impact

When test the underwater acoustic in the half-space which the sea-surface separate the free-space to,the conventional technology of PNAH can't be used to locate the underwater sound source.In order to solve the impact of the sea-surface reflection on the underwater acoustic testing,in this paper,use the method of mirror imaging to correct the sound field in the half-space.In this paper,introduce the principles and procedures of the method of mirror imaging to correct the sound field in the half-space.Simulate that make a sound field transformation of the corrected sound field in the half-space by the technology of planar near field acoustic holography in order to reconstruct the sound field of sound source surface.The simulation results show the influence of the sea-surface reflection on locating,and verify the effectiveness that use the method of mirror imaging to solve sea-surface reflection.Works above provide a reference for locating the underwater sound source.

Damage assessment of reinforced concrete flat slabs through modal tests using impact excitation

2019 ◽  
Vol 10 (2) ◽  
pp. 265-275 ◽  
Author(s):  
Gabriel S. Ferreira ◽  
Tulio O. Guedes ◽  
Lucas F. Melo ◽  
Márcio S. Gonçalves ◽  
Roberto Pimentel
Keyword(s):  
Reinforced Concrete ◽  
Natural Frequency ◽  
Damage Assessment ◽  
Crack Opening ◽  
Impact Excitation ◽  
Content Type ◽  
Rc Structures ◽  
Fundamental Natural Frequency ◽  
Cracking Pattern ◽  
The Impact

Purpose In reinforced concrete (RC) structures, an evidence of damage is the presence of cracking. In order to evaluate the effect of damage on cracking pattern and natural frequency in RC slabs, two of such structures with different dimensions and reinforcement ratios were tested, in which cracks were induced through application of static load, followed by modal tests using impact excitation. The paper aims to discuss this issue. Design/methodology/approach The gradient of the fundamental natural frequency along the decay, the crack opening rate and also a global damage index based on changes of the fundamental natural frequency were evaluated. Findings The behaviour of the aforementioned gradient was distinct for both slabs, increasing monotonically with the cracking level for the slab with lowest reinforcement ratio, and increasing until 33 per cent of the collapse load and then decreasing afterwards for the slab with the highest ratio. Changes of the gradient were consistent with changes of the crack opening rate. Both results of gradient changes and cracking pattern brought evidence that the balance between open (old) and breathing (new) cracks differed between the slabs, and may be responsible for such differences. Originality/value Damage assessment in RC structures using vibration tests is mostly concentrated on beams. In this work, an advance is made by investigating slabs. The lack of a unique pattern of changes of the gradient implies that its absolute value is not generally suitable for the association with the damage level. However, the impact tests can be effectively used to detect early damage on slabs using this proposed parameter.

Influence of the distribution of the shear walls on the seismic response of the buildings

2020 ◽  
Vol 15 (1) ◽  
pp. 37-44
Author(s):  
El Mehdi Echebba ◽  
Hasnae Boubel ◽  
Oumnia Elmrabet ◽  
Mohamed Rougui
Keyword(s):  
Structural Analysis ◽  
Seismic Response ◽  
Natural Frequency ◽  
Structural Design ◽  
Structural Response ◽  
Shear Walls ◽  
Structural Elements ◽  
Analysis Software ◽  
Ansys Apdl ◽  
The Impact

Abstract In this paper, an evaluation was tried for the impact of structural design on structural response. Several situations are foreseen as the possibilities of changing the distribution of the structural elements (sails, columns, etc.), the width of the structure and the number of floors indicates the adapted type of bracing for a given structure by referring only to its Geometric dimensions. This was done by studying the effect of the technical design of the building on the natural frequency of the structure with the study of the influence of the distribution of the structural elements on the seismic response of the building, taking into account of the requirements of the Moroccan earthquake regulations 2000/2011 and using the ANSYS APDL and Robot Structural Analysis software.

Stability Analysis of Moving Printing Web With Sine Half-Wave Variable Density Based on Differential Quadrature Method

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Jimei Wu ◽  
Mingyue Shao ◽  
Yan Wang ◽  
Qiumin Wu ◽  
Fan Zhao
Keyword(s):  
Flexible Electronics ◽  
Transverse Vibration ◽  
Differential Quadrature Method ◽  
Variable Density ◽  
Differential Quadrature ◽  
Printing Press ◽  
Quadrature Method ◽  
Half Wave ◽  
The Impact ◽  
Density Coefficient

The moving web is widely used to make printing and packaging products, flexible electronics, cloths, etc. The impact of the variable density on printing web dynamic behavior is considered. The density changes in the form of sine half-wave in the lateral direction. Based on the D'Alembert's principle, the transverse vibration differential equation of moving printing web with variable density is established and is discretized by using the differential quadrature method (DQM). The complex characteristic equation is derived. The impacts of the density coefficient and the dimensionless speed on the web stability and vibration characteristics are discussed. The results show that it is feasible to use the DQM to analyze the problem of transverse vibration of printing web with varying density; the tension ratio and the density coefficient have important impacts on the stability of moving printing web. This study provides theoretical guidance and basis for optimizing the structure of printing press and improving the stable working speed of printing press and web.

Sheet Material Property Effects upon Dynamic Behavior in Self-Pierce Riveted Joints

2011 ◽  
Vol 675-677 ◽  
pp. 999-1002 ◽  
Author(s):  
Xiao Cong He
Keyword(s):  
Natural Frequency ◽  
Transverse Vibration ◽  
Spot Welding ◽  
Sheet Material ◽  
Vibration Characteristics ◽  
Efficient Design ◽  
Material Density ◽  
Sheet Materials ◽  
Riveted Joints ◽  
Free Transverse Vibration

Self-pierce riveting (SPR) technology offers an alternative to resistance spot welding (RSW) for joining sheet materials. It has been found that the SPR technology produced a much stronger joint than the RSW in fatigue test. For efficient design of SPR structures, the knowledge of dynamic characteristics of the SPR beams is essential. In this paper, the free transverse vibration characteristics of single lap-jointed cantilevered SPR beams are investigated in detail. The focus of the analysis is to reveal the influence on the natural frequency and natural frequency ratio of these beams caused by variations in the material properties of sheet materials to be jointed. It is shown that the transverse natural frequencies of single lap jointed cantilevered SPR beams increase significantly as the Young’s modulus of the sheet materials increases, but change slightly corresponding to the change in Poisson’s ratio. It is also found that the material density of the sheets have significant effects on the free transverse vibration characteristics of the beams.

A Dynamic Test of Fully Prestressed Concrete Beams

2011 ◽  
Vol 368-373 ◽  
pp. 2483-2490
Author(s):  
Yao Ting Zhang ◽  
Yi Zheng ◽  
Hong Jian Li
Keyword(s):  
Experimental Data ◽  
Elastic Modulus ◽  
Theoretical Analysis ◽  
Natural Frequency ◽  
Axial Force ◽  
Prestressed Concrete ◽  
Concrete Beams ◽  
Dynamic Test ◽  
Modified Formula

A dynamic test of two unbonded fully prestressed concrete beams has been conducted. The results indicate that the natural frequency of beams increases with the prestress force, which is opposite to the analytical arguments for homogeneous and isotropic beams subject to axial force. This paper explains the change in frequencies by discussing the change in the elastic modulus. A modified formula is also proposed, and the experimental data agree well with the theoretical analysis.

Component Rearrangement on Printed Wiring Boards to Maximize the Fundamental Natural Frequency

1993 ◽  
Vol 115 (3) ◽  
pp. 312-321 ◽  
Author(s):  
Tien-Sheng Chang ◽  
E. B. Magrab
Keyword(s):  
Simulated Annealing ◽  
Boundary Conditions ◽  
Natural Frequency ◽  
Printed Wiring Board ◽  
Computationally Efficient ◽  
Additional Increase ◽  
Simulated Annealing Method ◽  
Fundamental Natural Frequency ◽  
Rearrangement Algorithm ◽  
Annealing Method

A methodology to attain the highest fundamental natural frequency of a printed wiring board by rearranging its components has been developed. A general two-dimensional rearrangement algorithm is developed by which the rearrangement of the component-lead-board (CLB) assemblies is performed automatically for any combination of equal size, unequal size, movable and immovable CLBs. This algorithm is also capable of incorporating two design restrictions: fixed (immovable) components and prohibited (non-swappable) areas. A highly computationally efficient objective function for the evaluation of the automatic rearrangement process is introduced, which is a linear function of the size of the individual CLBs that have been selected for each interchange. The simulated annealing method is adapted to solve the combinatorial rearrangement of the CLBs. Using 61 combinations of boundary conditions, equal and unequal sized CLBs, movable and immovable CLBs, various CLB groupings and sets of material properties, it is found that, when compared to the exact solution obtained by an exhaustive search method, the simulated annealing method obtained the highest fundamental natural frequency within 1 percent for 87 percent of the cases considered, within 0.5 percent for 72 percent of the cases and the true maximum in 43 percent of them. To further increase the fundamental natural frequency the introduction of a single interior point support is analyzed. Depending on the boundary conditions an additional increase in the maximum fundamental natural frequency of 44 to 198 percent can be obtained.

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