Numerical simulation regarding flow-induced noise in variable cross-section pipelines based on large eddy simulations and Ffowcs Williams–Hawkings methods

A model for wave propagation in variable cross-section bars is developed. Then a numerical simulation method based on CSPM is introduced. Furthermore the wave propagations in stepped bars and conical bars are simulated. The simulation results agree well with the analytical solutions, which demonstrate that the model can describe the wave propagation in variable cross-section bars precisely.

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Analysis of the distribution of BAD generated during the normal penetration of a variable cross-section EFP on RHA

2019 15th Hypervelocity Impact Symposium ◽

10.1115/hvis2019-003 ◽

2019 ◽

Author(s):

Boyang XING ◽

Yunhui HOU ◽

Zhenyan GUO ◽

Dongjiang ZHANG ◽

Liang CHEN ◽

...

Keyword(s):

Numerical Simulation ◽

Impact Velocity ◽

Cross Section ◽

Variable Cross Section ◽

Variable Cross ◽

Thin Target ◽

The Impact

Abstract The purpose of this study is to analyse how the thickness of Rolled Homogeneous Armor (RHA) and impact velocity of an Explosively Formed Projectile (EFP) influence the middle mass behind-armor debris (BAD) when a variable cross-section EFP penetrates RHA normally. Numerical simulation is adopted, the thickness of RHA varies from 10mm to 70mm, and the impact velocity of the EFP varies from 1650m/s to 1860m/s. The results indicate that: (1) when the impact velocity of the EFP is 1650m/s and the thickness of RHA varies from 10mm to 70mm, p1g of the RHA and EFP decreases with increasing H0. The thin target could be used to produce a large proportion of the middle mass BAD from RHA (including BAD from the EFP and BAD from the RHA and EFP). (2) When the impact velocity of the EFP varies from 1650m/s to 1860m/s and the thickness of the RHA is 40mm, p1g of the RHA is less than 50%, p1g of the EFP is more than 70%, and p1g of the RHA and EFP is more than 50%.

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Optimization of Process Parameters of Tube Hydroforming Based on Orthogonal Experiment

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.80-81.542 ◽

2011 ◽

Vol 80-81 ◽

pp. 542-545

Author(s):

Ji Tao Du ◽

Cheng Zhan Chen ◽

Can Huang ◽

Qi Jun Chen

Keyword(s):

Numerical Simulation ◽

Cross Section ◽

Axial Force ◽

Orthogonal Experiment ◽

Tube Hydroforming ◽

Variable Cross Section ◽

Reduction Ratio ◽

Thickness Reduction ◽

Variable Cross ◽

Optimization Of Process Parameters

Numerical simulation was made on parameters like internal pressure and axial force as well as friction coefficient of tube that affect the formation of variable cross-section tube. Through numerical simulation and orthogonal optimization, the most thickness reduction ratio and thickness uniformity on different conditions were contrasted and analyzed. An optimum scheme was obtained and it could improve the formability of variable cross-section tube. The result indicates that the axial force plays the most important role on thickness reduction ratio. The result provides technical support for the variable cross-section tube hydroforming research.

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