Noise attenuation of an insertion‐type hearing protector by mathematical model and experimental verification

2000 ◽  
Vol 108 (5) ◽  
pp. 2621-2621
Author(s):  
Samir N. Y. Gerges ◽  
Elizabete Y. N. Bavastri ◽  
Roberto A. Tenenbaum
Keyword(s):  
Mathematical Model ◽  
Experimental Verification ◽  
Noise Attenuation ◽  
Hearing Protector

scholarly journals Pneumatic Adaptive Absorber: Mathematical Modelling with Experimental Verification

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Grzegorz Mikułowski ◽  
Rafał Wiszowaty
Keyword(s):  
Mathematical Model ◽  
Mathematical Modelling ◽  
Experimental Verification ◽  
Load Capacity ◽  
Mechanical Energy ◽  
Specific Situation ◽  
Engineering Structures ◽  
Piston Cylinder ◽  
Proposed Model ◽  
Energy Absorbers

Many of mechanical energy absorbers utilized in engineering structures are hydraulic dampers, since they are simple and highly efficient and have favourable volume to load capacity ratio. However, there exist fields of applications where a threat of toxic contamination with the hydraulic fluid contents must be avoided, for example, food or pharmacy industries. A solution here can be a Pneumatic Adaptive Absorber (PAA), which is characterized by a high dissipation efficiency and an inactive medium. In order to properly analyse the characteristics of a PAA, an adequate mathematical model is required. This paper proposes a concept for mathematical modelling of a PAA with experimental verification. The PAA is considered as a piston-cylinder device with a controllable valve incorporated inside the piston. The objective of this paper is to describe a thermodynamic model of a double chamber cylinder with gas migration between the inner volumes of the device. The specific situation considered here is that the process cannot be defined as polytropic, characterized by constant in time thermodynamic coefficients. Instead, the coefficients of the proposed model are updated during the analysis. The results of the experimental research reveal that the proposed mathematical model is able to accurately reflect the physical behaviour of the fabricated demonstrator of the shock absorber.

A Hysteresis Restoring Force Model of Disc-Shaped Metal Rubber Isolation Component

2012 ◽  
Vol 271-272 ◽  
pp. 186-189 ◽  
Author(s):  
Feng Li Cao ◽  
Hong Bai Bai ◽  
Zhong Bo He ◽  
Guo Quan Ren
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Experimental Verification ◽  
Vibration Isolation ◽  
Practical Significance ◽  
Force Model ◽  
Stiffness Coefficient ◽  
Restoring Force ◽  
Restoring Force Model ◽  
Metal Rubber

Dynamic load experiments of the disc-shaped metal rubber isolation component are performed. Through analyzing variation law of the parameters with amplitude and frequency, which are stiffness coefficient, damping coefficient and damping component factor, the hysteresis restoring force model which is able to fully reveal the dynamic characteristics of the component is established. The experimental verification results show that the theoretic calculations are consistent with the experimental data, which verifies the practicability and effectiveness of mathematical model and parameter identification. It has important practical significance for design of vibration isolation component with different requirements.

scholarly journals Modeling of Pressure Drop During Refrigerant Condensation in Pipe Minichannels

2017 ◽  
Vol 38 (4) ◽  
pp. 15-28 ◽  
Author(s):  
Małgorzata Sikora ◽  
Tadeusz Bohdal
Keyword(s):  
Mathematical Model ◽  
Pressure Drop ◽  
Computer Modeling ◽  
Experimental Verification ◽  
Flow Resistance ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Flow Conditions ◽  
Conservation Equations ◽  
Mathematical And Computer Modeling

Abstract Investigations of refrigerant condensation in pipe minichannels are very challenging and complicated issue. Due to the multitude of influences very important is mathematical and computer modeling. Its allows for performing calculations for many different refrigerants under different flow conditions. A large number of experimental results published in the literature allows for experimental verification of correctness of the models. In this work is presented a mathematical model for calculation of flow resistance during condensation of refrigerants in the pipe minichannel. The model was developed in environment based on conservation equations. The results of calculations were verified by authors own experimental investigations results.

Rig Test and Analysis of Dynamic Engagement Process of Wet Clutch

2014 ◽  
Vol 945-949 ◽  
pp. 1461-1464
Author(s):  
Han Yu Jin ◽  
Xiu Sheng Cheng ◽  
Xiu Feng Song
Keyword(s):  
Mathematical Model ◽  
Experimental Verification ◽  
Constant Pressure ◽  
Simulation Analysis ◽  
Test Rig ◽  
Wet Clutch ◽  
Engagement Process ◽  
Working Principle ◽  
The Mathematical Model

The working principle of wet clutch was analyzed and the mathematical model was established for torque deliver. Experimental verification and simulation analysis was carried out for the clutch model in the situation of constant pressure engaging process. An efficiency examination of wet clutch implemented on the test rig and provided theory evidence for pressure precisely control.

The Biot Model and Its Application in Viscoelastic Composite Structures

2007 ◽  
Vol 129 (5) ◽  
pp. 533-540 ◽  
Author(s):  
J. Zhang ◽  
G. T. Zheng
Keyword(s):  
Mathematical Model ◽  
Dynamic Behavior ◽  
Composite Structures ◽  
Optimization Method ◽  
Noise Attenuation ◽  
Viscoelastic Materials ◽  
Numerical Techniques ◽  
Viscoelastic Composite ◽  
Biot Model ◽  
Numerical Examples

Application of viscoelastic materials in vibration and noise attenuation of complicated machines and structures is becoming more and more popular. As a result, analytical and numerical techniques for viscoelastic composite structures have received a great deal of attention among researchers in recent years. Development of a mathematical model that can accurately describe the dynamic behavior of viscoelastic materials is an important topic of the research. This paper investigates the procedure of applying the Biot model to describe the dynamic behavior of viscoelastic materials. As a minioscillator model, the Biot model not only possesses the capability of its counterpart, the GHM (Golla-Hughes-McTavish) model, but also has a simpler form. Furthermore, by removing zero eigenvalues, the Biot model can provide a smaller-scale mathematical model than the GHM model. This procedure of dimension reduction is studied in detail here. An optimization method for determining the parameters of the Biot model is also investigated. With numerical examples, these merits, the computational efficiency, and the accuracy of the Biot model are illustrated and proved.

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