scholarly journals Transverse impact performance and finite element analysis of three dimensional braided composite tubes with different braiding layers

2017 ◽  
Vol 168 ◽  
pp. 345-359 ◽  
Author(s):  
Haili Zhou ◽  
Dongmei Hu ◽  
Bohong Gu ◽  
Baozhong Sun
2016 ◽  
Vol 26 (7) ◽  
pp. 1003-1027 ◽  
Author(s):  
Xianyan Wu ◽  
Qian Zhang ◽  
Bohong Gu ◽  
Baozhong Sun

This article reports the longitudinal compressive crashworthiness of three-dimensional four-step circular braided carbon/epoxy composite tubes at temperatures of 23, −50, and −100℃ under strain rate ranging from 340 to 760/s both experimentally and finite element analysis. The experimental results showed that the compression strength, stiffness, and specific energy absorption increased with the decrease in temperature and with the increase in strain rate. It also showed that, the compressive damage morphologies were sensitive to the change in temperature and strain rate. A coupled thermal-mechanical numerical analysis was conducted to find the thermo/mechanical coupling effect on the compressive crashworthiness of the three-dimensional composite tube. The temperature distributions in the braided preform and the resin during the impact compression were also calculated through finite element analysis. From the finite element analysis results, the inelastic heat generation was seen to be more in the preform than the matrix and its distribution and accumulation led to the damage progress along the loading direction.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


2012 ◽  
Vol 24 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Yu-Chi Chen ◽  
Wen-Ching Ko ◽  
Han-Lung Chen ◽  
Hsu-Ching Liao ◽  
Wen-Jong Wu ◽  
...  

We propose a model to give us a method to investigate the characteristic three-dimensional directivity in an arbitrarily configured flexible electret-based loudspeaker. In recent years, novel electret loudspeakers have attracted much interest due to their being lightweight, paper thin, and possessing excellent mid- to high-frequency responses. Increasing or decreasing the directivity of an electret loudspeaker makes it excellent for adoption to many applications, especially for directing sound to a particular area or specific audio location. Herein, we detail a novel electret loudspeaker that possesses various directivities and is based on various structures of spacers instead of having to use multichannel amplifiers and a complicated digital control system. In order to study the directivity of an electret loudspeaker based on an array structure which can be adopted for various applications, the horizontal and vertical polar directivity characteristics as a function of frequency were simulated by a finite-element analysis model. To validate the finite-element analysis model, the beam pattern of the electret loudspeaker was measured in an anechoic room. Both the simulated and experimental results are detailed in this article to validate the various assertions related to the directivity of electret cell-based smart speakers.


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