Direction estimation of ship volume target based on a non-typical vector sound intensity array

Author(s):  
Jie Shi ◽  
Xiao-min Zhang ◽  
Peng Han ◽  
Jian Luo
Author(s):  
Sterling McBride ◽  
Ricardo Burdisso ◽  
Corina Sandu

ABSTRACT Tire-pavement interaction noise (TPIN) is one of the main sources of exterior noise produced by vehicles traveling at greater than 50 kph. The dominant frequency content is typically within 500–1500 Hz. Structural tire vibrations are among the principal TPIN mechanisms. In this work, the structure of the tire is modeled and a new wave propagation solution to find its response is proposed. Multiple physical effects are accounted for in the formulation. In an effort to analyze the effects of curvature, a flat plate and a cylindrical shell model are presented. Orthotropic and nonuniform structural properties along the tire's transversal direction are included to account for differences between its sidewalls and belt. Finally, the effects of rotation and inflation pressure are also included in the formulation. Modeled frequency response functions are analyzed and validated. In addition, a new frequency-domain formulation is presented for the computation of input tread pattern contact forces. Finally, the rolling tire's normal surface velocity response is coupled with a boundary element model to demonstrate the radiated noise at the leading and trailing edge locations. These results are then compared with experimental data measured with an on-board sound intensity system.


2018 ◽  
Vol 6 (02) ◽  
pp. 105-120
Author(s):  
Muhammad Rouf Suprayogi ◽  
Annisa Mufida ◽  
Edwin Azwar

In composite science, desirable materials that are lighter but have the power and quality that can match or even exceed the material that has been there before. The purpose of this study was to investigate the effect of cellulose fiber addition from banana gedebok to tensile strength, compressive strength and damping of concrete composite sound. To achieve this objective, mixing of cellulose fibers with K-275 quality concrete mix with variation of 0% and 5% substitution in which the cellulose is varied in powder and wicker form. Delignification of lignin content from banana gedebok was done by soaking and drying method without any variation and yielding powder having cellulose content of 13,0388%, hemicellulose 18,2796% and lignin 0,6684%. This study produces concrete composites that have a tensile strength and a compressive strength lower than that of normal concrete. Normally reinforced concrete tensile strength value 94.5 kg / cm2, 71.4 kg / cm2 cellulose powder concrete and 90.3 kg / cm2 cellulose woven concrete. Normal concrete compressive strength value 334,22 kg / cm2, cellulose powder concrete 215,7 kg / cm2, and cellulose webbing concrete 157,98 kg / cm2. As for the power damping sound of cellulose webbing concrete has the highest damping power compared to other concrete with the absorbed sound intensity that is 52-68 dB


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