SOUND INSULATION OF A MECHANICAL WORKSHOP

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
ZORAN PETROVIĆ ◽  
BRANKO RADIČEVIĆ ◽  
MILAN KOLAREVIĆ ◽  
VLADAN GRKOVIĆ
Keyword(s):  
Theoretical Model ◽  
Key Words ◽  
Design Process ◽  
Experimental Results ◽  
Sound Insulation ◽  
Housing Estate ◽  
Noise Levels ◽  
Acoustic Insulation

The paper presents a design process related to sound insulation of a small mechanical workshop for storing eccentric presses, which is located in a densely populated housing estate. Starting from the theoretical model of acoustic insulation power of a single solid partition, a complex partition and a multi-layer partition, the acoustic insulation power of the walls and the ceiling in the workshop was determined. The results of calculation of workshop isolation coincide to a great extent with the experimental results of measuring noise levels. Key words: noise, mechanical workshop, sound insulation

scholarly journals Comparasion of prediction and measurement methods for sound insulation of lightweight partitions

2012 ◽  
Vol 10 (2) ◽  
pp. 155-167 ◽  
Author(s):  
Momir Prascevic ◽  
Dragan Cvetkovic ◽  
Darko Mihajlov
Keyword(s):  
Transmission Loss ◽  
Road Traffic ◽  
Theoretical Models ◽  
Measurement Methods ◽  
Experimental Results ◽  
Sound Insulation ◽  
Acoustic Absorption ◽  
Noise Levels ◽  
Overall Design ◽  
Acoustic Comfort

It is important to know the sound insulation of partitions in order to be able to compare different constructions, calculate acoustic comfort in apartments or noise levels from outdoor sources such as road traffic, and find engineer optimum solutions to noise problems. The use of lightweight partitions as party walls between dwellings has become common because sound insulation requirements can be achieved with low overall surface weights. However, they need greater skill to design and construct, because the overall design is much more complex. It is also more difficult to predict and measure of sound transmission loss of lightweight partitions. There are various methods for predicting and measuring sound insulation of partitions and some of them will be described in this paper. Also, this paper presents a comparison of experimental results of the sound insulation of lightweight partitions with results obtained using different theoretical models for single homogenous panels and double panels with and without acoustic absorption in the cavity between the panels.

scholarly journals Evaluation Method for Façade Acoustic Insulation for a Corner Room: Discussion on the Results Obtained as a Function of the Source Position

2020 ◽  
Vol 10 (21) ◽  
pp. 7434
Author(s):  
Nicola Granzotto ◽  
Edoardo Alessio Piana
Keyword(s):  
Sound Source ◽  
Evaluation Method ◽  
International Standards ◽  
Sound Insulation ◽  
Source Position ◽  
Noise Levels ◽  
Acoustic Attenuation ◽  
Acoustic Insulation ◽  
Building Facades ◽  
The Individual

The appropriate acoustic insulation project of building façades is of importance for the design of highly comfortable living environments. In some countries, national regulations require maximum noise levels inside rooms, or minimum sound insulation limits, to be respected. The acoustic insulation design of a façade is usually performed according to the ISO 12354-3 standard, which presents a calculation method based on the geometry of the room, the shape of the façade, the areas and the acoustic performances of the individual elements. The prescribed limits must be experimentally verified according to methods derived from international standards. However, the current versions of such standards do not provide details on how to perform the measurements and the calculation of the sound insulation for corner rooms. An important remark is that, depending on the position of the sound source used for the measurements, different results of the standardized sound insulation are obtained. This article proposes a new method for calculating the façade insulation of corner rooms by introducing the acoustic attenuation due to the diffraction of the corner and the distance of the sound source from the façades, estimated through simulations and experimentally validated.

Actuation and dynamic mechanical characteristics of a core free flat dielectric electro-active polymer soft actuator

2020 ◽  
Vol 14 (4) ◽  
pp. 7396-7404
Author(s):  
Abdul Malek Abdul Wahab ◽  
Emiliano Rustighi ◽  
Zainudin A.
Keyword(s):  
Theoretical Model ◽  
Resonance Frequency ◽  
Dynamic Testing ◽  
Experimental Results ◽  
Percentage Error ◽  
Initial Tension ◽  
Average Percentage ◽  
Soft Actuator ◽  
Average Percentage Error ◽  
Mechanical Dynamics

Various complex shapes of dielectric electro-active polymer (DEAP) actuator have been promoted for several types of applications. In this study, the actuation and mechanical dynamics characteristics of a new core free flat DEAP soft actuator were investigated. This actuator was developed by Danfoss PolyPower. DC voltage of up to 2000 V was supplied for identifying the actuation characteristics of the actuator and compare with the existing formula. The operational frequency of the actuator was determined by dynamic testing. Then, the soft actuator has been modelled as a uniform bar rigidly fixed at one end and attached to mass at another end. Results from the theoretical model were compared with the experimental results. It was found that the deformation of the current actuator was quadratic proportional to the voltage supplied. It was found that experimental results and theory were not in good agreement for low and high voltage with average percentage error are 104% and 20.7%, respectively. The resonance frequency of the actuator was near 14 Hz. Mass of load added, inhomogeneity and initial tension significantly affected the resonance frequency of the soft actuator. The experimental results were consistent with the theoretical model at zero load. However, due to inhomogeneity, the frequency response function’s plot underlines a poor prediction where the theoretical calculation was far from experimental results as values of load increasing with the average percentage error 15.7%. Hence, it shows the proposed analytical procedure not suitable to provide accurate natural frequency for the DEAP soft actuator.

scholarly journals Analysis of the transmission loss of double-leaf panels with an equivalent spring–mass model for studs

2020 ◽  
Vol 37 ◽  
pp. 126-133
Author(s):  
Yuan-Wei Li ◽  
Chao-Nan Wang
Keyword(s):  
Distribution Curve ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Experimental Results ◽  
Sound Insulation ◽  
Sound Transmission Loss ◽  
Mass Model ◽  
Steel Stud ◽  
Panel Thickness ◽  
Stiffness Distribution

Abstract The purpose of this study was to investigate the sound insulation of double-leaf panels. In practice, double-leaf panels require a stud between two surface panels. To simplify the analysis, a stud was modeled as a spring and mass. Studies have indicated that the stiffness of the equivalent spring is not a constant and varies with the frequency of sound. Therefore, a frequency-dependent stiffness curve was used to model the effect of the stud to analyze the sound insulation of a double-leaf panel. First, the sound transmission loss of a panel reported by Halliwell was used to fit the results of this study to determine the stiffness of the distribution curve. With this stiffness distribution of steel stud, some previous proposed panels are also analyzed and are compared to the experimental results in the literature. The agreement is good. Finally, the effects of parameters, such as the thickness and density of the panel, thickness of the stud and spacing of the stud, on the sound insulation of double-leaf panels were analyzed.

scholarly journals MEMS-Based Electrochemical Seismometer with a Sensing Unit Integrating Four Electrodes

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 699
Author(s):  
Wenjie Qi ◽  
Chao Xu ◽  
Bowen Liu ◽  
Xu She ◽  
Tian Liang ◽  
...  
Keyword(s):  
Ground Motions ◽  
Experimental Results ◽  
Glass Layer ◽  
Noise Levels ◽  
Stabilization Time ◽  
New Process ◽  
Accuracy Parameter ◽  
Peak Sensitivity ◽  
High Consistency ◽  
Four Electrodes

This paper presents a new process to fabricate a sensing unit of electrochemical seismometers using only one silicon–glass–silicon bonded wafer. By integrating four electrodes on one silicon–glass–silicon bonded wafer, the consistency of the developed sensing unit was greatly improved, benefiting from the high alignment accuracy. Parameter designs and simulations were carried out based on this sensing unit, which indicated that the sensitivities of the developed electrochemical seismometer decreased with the decrease in the number of flow holes in the sensing unit, and the initial stabilization time decreased gradually with the decrease in the thickness of the glass layer. Based on experimental results of four devices, the peak sensitivity was quantified as 5345.45 ± 43.78 V/(m/s) at 2 Hz, which proved high consistency of the fabricated electrochemical seismometer. In terms of the responses to random ground motions, high consistencies between the developed electrochemical seismometer and the commercial counterpart of CME6011 (R-sensors, Moscow, Russia) were found, where the developed electrochemical seismometer produced comparable noise levels to those of CME6011. These results validated the performance of the device and it may function as an effective tool for a variety of applications.

Design thinking in printing graphic design approaches for animation films

2021 ◽  
Vol 26 ◽  
pp. 709-728
Keyword(s):  
Key Words ◽  
Design Process ◽  
Graphic Design ◽  
Scientific Theory ◽  
Design Thinking ◽  
Film Industry ◽  
Optical Illusion ◽  
Design Work ◽  
Aesthetic Awareness

Art of animation as an analysis of movement is based on the theory that the vision remains on the eye after the disappearance of the actual image, and this scientific theory is the same that the film industry was built upon. Recently, various techniques and ideas have entered the print design process as a means of expressing a phenomenon subject to the human will to change and elevate our aesthetic awareness and feelings, which rise in various forms of designs that reveal themselves in design work and are embodied in animation films. The design artwork falls within a group of intertwined elements fused with each other, reflecting the peculiarity of this work, as it is innovation and creating new and interesting things, so that the design is suitable for the desired purpose and beautifully. Perhaps the simplest type of optical illusion that can clarify to us the idea of the impression of the existence of an image that does not actually exist is represented in the decree paper. Key words: Design thinking, Typography, Animation films

scholarly journals Investigation of thermal conductivity of single-wall carbon nanotubes

2011 ◽  
Vol 15 (2) ◽  
pp. 565-570 ◽  
Author(s):  
Mahmoud Jafari ◽  
Majid Vaezzadeh ◽  
Momhamad Mansouri ◽  
Abazar Hajnorouzi
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Theoretical Model ◽  
Potential Energy ◽  
Experimental Results ◽  
Single Wall Carbon Nanotubes ◽  
Lattice Vibrations ◽  
Single Wall Carbon ◽  
Thermal Potential ◽  
Conductivity Behavior

In this paper, the thermal conductivity of Single-wall carbon nanotubes (SWCNTs) is determined by lattice vibrations (phonons) and free elections. The thermal conductivity of SWCNTs is modeled up to 8-300 K and the observed deviations in K-T figures of SWCNTs are explained in terms of phonon vibrations models. An suitable theoretical model is shown for thermal conductivity behavior with respect to temperature and is generalized for experimental results. This model enables us to calculate thermal conductivity SWNTs and Thermal Potential Energy (TPE).

scholarly journals MEMS-Based Integrated Triaxial Electrochemical Seismometer

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1156
Author(s):  
Wenjie Qi ◽  
Bowen Liu ◽  
Tian Liang ◽  
Jian Chen ◽  
Deyong Chen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Ground Motion ◽  
Small Volume ◽  
Three Dimensional ◽  
Experimental Results ◽  
Good Prospect ◽  
High Symmetry ◽  
Noise Levels ◽  
Sensitivity Curves ◽  
Simulation Results

This paper presents a micro-electromechanical systems (MEMS)-based integrated triaxial electrochemical seismometer, which can detect three-dimensional vibration. By integrating three axes, the integrated triaxial electrochemical seismometer is characterized by small volume and high symmetry. The numerical simulation results inferred that the integrated triaxial electrochemical seismometer had excellent independence among three axes. Based on the experimental results, the integrated triaxial electrochemical seismometer had the advantage of small axial crosstalk and could detect vibration in arbitrary directions. Furthermore, compared with the uniaxial electrochemical seismometer, the integrated triaxial electrochemical seismometer had similar sensitivity curves ranging from 0.01 to 100 Hz. In terms of random ground motion response, high consistencies between the developed integrated triaxial electrochemical seismometer and the uniaxial electrochemical seismometer could be easily observed, which indicated that the developed integrated triaxial electrochemical seismometer produced comparable noise levels to those of the uniaxial electrochemical seismometer. These results validated the performance of the integrated triaxial electrochemical seismometer, which has a good prospect in the field of deep geophysical exploration and submarine seismic monitoring.

Theoretical Model for Interfacial Nonlinear Bond Softening Behavior between Embedded Steel and HSHPC

2007 ◽  
Vol 348-349 ◽  
pp. 845-848
Author(s):  
Shan Suo Zheng ◽  
Lei Li ◽  
Guo Zhuan Deng ◽  
Shun Li Che ◽  
Wei Zhao
Keyword(s):  
Theoretical Model ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Nonlinear Process ◽  
Experimental Results ◽  
Interfacial Bond ◽  
Bond Slip ◽  
Softening Behavior ◽  
Bond Softening

The latest experimental study on steel reinforced high strength and high performance concrete (SRHSHPC) specimens shows that there exists interfacial bond softening phenomenon between embedded steel and high strength and high performance concrete (HSHPC), and it makes the shear transfer capacity between shaped steel and HSHPC be progressively reduced. To predict failure load in design, a theoretical model for interfacial bond softening behavior is required. As interfacial bond softening behavior is a nonlinear process involving material properties, it can be analyzed once the relation of interfacial bond stress (τ ) and slippage ( s ) is known. In this paper, the mechanism of interfacial bond-slip is studied, thus a simplified τ − s relation including ascending and descending parts is proposed and employed to analyze the interfacial nonlinear bond-slip process. Based on the interfacial equilibrium between steel and HSHPC as well as the τ − s relation, the basic governing equations in both softened region and elastic region are established and solved for steel strain or stress. At last, the application of the model is verified through comparison with experimental results. The calculating results of the model are found to be in good agreement with experimental results, showing that the model can describe the bond-slip process in real material systems.

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