scholarly journals Numerical study of fragments from cylindrical casing with one of end caps fully constrained

2021 ◽  
Vol 1996 (1) ◽  
pp. 012006
Author(s):  
Yue-guang Gao ◽  
Shun-shan Feng ◽  
Yun Chen ◽  
Xiang Xiao ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Optimal Design ◽  
Detonation Wave ◽  
Simulation Analysis ◽  
Numerical Study ◽  
Normal Pressure ◽  
Mach Stem ◽  
Constraint Condition ◽  
Detonation Products ◽  
Cylindrical Casing ◽  
End Caps

Abstract In order to study the process and characteristic of the fragments in the warhead with one end cap under full constraint condition, we established a cylindrical casing with two end caps which one of them was fully constrained using the simulation analysis. The result showed that the fragmentation of cylindrical casing with one end full constrained has its own characteristic. The Mach stem was generated when the detonation wave propagated to the fully constrained end cap under the condition of one end detonation, working on unreactive explosives and causing the nearby fragment subjected to nearly 2.5 times the normal pressure to obtain a higher speed. The cylindrical casing first ruptured at the contact surface with the fully constrained end, and then at the end cover of the initiating end, and then the rupture extends to the whole cylindrical casing. The detonation products started to leak out from the rupture. driving fragments to fly, and forming two dense flying areas. The analysis of this paper can provide a reference for the optimal design of this kind of warhead.

scholarly journals Numerical study of detonation wave propagation modes in annular channels

AIP Advances ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 085203
Author(s):  
Duo Zhang ◽  
Xueqiang Yuan ◽  
Shijie Liu ◽  
Xiaodong Cai ◽  
Haoyang Peng ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Detonation Wave ◽  
Numerical Study ◽  
Annular Channels ◽  
Detonation Wave Propagation

scholarly journals 3-D Numerical Study of Mechanical Behaviors of Pile-Anchor System

2014 ◽  
Vol 580-583 ◽  
pp. 238-242
Author(s):  
Ri Cheng Liu ◽  
Bang Shu Xu ◽  
Bo Li ◽  
Yu Jing Jiang
Keyword(s):  
Simulation Analysis ◽  
Numerical Study ◽  
Bending Moments ◽  
Mechanical Behaviors ◽  
Foundation Pit ◽  
Anchor System ◽  
Anchor Cable ◽  
Axial Forces ◽  
Toppling Failure ◽  
Potential Failure

Mechanical behaviors of pile-soil effect and anchor-soil effect are significantly important in supporting engineering activities of foundation pit. In this paper, finite difference method (FDM) was utilized to perform the numerical simulation of pile-anchor system, composed of supporting piles and pre-stressed anchor cables. Numerical simulations were on the basis of the foundation pit of Jinan’s West Railway Station, and 3D simulation analysis of foundation pit has been prepared during the whole processes of excavation, supporting and construction. The paper also analyzed the changes of bending moments of piles and axial forces of cables, and discussed mechanical behaviors of pile-anchor system, through comparisons with field monitoring. The results show that the parameters concluding vertical gridding’s number, cohesion of pile and soil, and pile stiffness have robust influences on supporting elements’ behaviors. Mechanical behaviors of supporting pile and axial forces of anchor cable changed dramatically, indicating that the potential failure form was converted from toppling failure to sliding failure.

scholarly journals Optimal Design and Simulation Analysis of Spike Tooth Threshing Component Based on DEM

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1163
Author(s):  
Yajun Yu ◽  
Liangshan Li ◽  
Jiale Zhao ◽  
Xiangeng Wang ◽  
Jun Fu
Keyword(s):  
Optimal Design ◽  
Simulation Analysis ◽  
Process Analysis ◽  
Structural Parameters ◽  
Compressive Force ◽  
Microscopic Analysis ◽  
Analysis Software ◽  
Damage Rate ◽  
Tooth Type ◽  
Simulation Time

This paper takes a local drum-type corn thresher as an example. In order to make the threshing principle transform to the plate-tooth type, the width of the spike-tooth threshing component is increased gradually, and three threshing components of different shape and size are selected as the research objects. Based on the preliminary experimental research, the corn threshing process is simulation analyzed using the self-developed corn threshing process analysis software. The effects of the width of the threshing component on the corn ears threshing rate and kernel damage rate under different rates of drum rotation were studied from a macroscopic perspective. The results show that with the increase of drum rotation rate, both the corn ear threshing rate and kernel damage rate increase; with the increase of threshing component width, the threshing rate increases and the damage rate decreases; and when the component width is too large, the stacking between adjacent components has an impact on the threshing performance. The effects of threshing component width on the amount of kernel threshing and the total compressive force during the simulation time were investigated from microscopic perspective at different rates of drum rotation, and the results show that the microscopic analysis is consistent with the macroscopic analysis. Therefore, the optimization of the structural parameters and operating parameters of the threshing component was achieved. When the width of the threshing component was 25 mm and the roller speed was 187.50 rpm, the threshing performance was optimal, with a 98.04% corn ears threshing rate and a 2.56% kernel damage rate. This paper verifies the practical applicability of the corn threshing process analysis software and provides a reference for the optimal design of threshing devices.

Numerical Study of the Detonation Wave Structure in a Linear Model Detonation Engine

2018 ◽  
Author(s):  
Supraj Prakash ◽  
Romain Fiévet ◽  
Venkatramanan Raman ◽  
Jason R. Burr ◽  
Kenneth H. Yu
Keyword(s):  
Detonation Wave ◽  
Linear Model ◽  
Numerical Study ◽  
Wave Structure ◽  
Detonation Engine

Numerical Study of Detonation Propagation in an Insensitive High Explosive Arc with Confinement Materials

2020 ◽  
pp. 2050117
Author(s):  
Yupei Qin ◽  
Kuibang Huang ◽  
Huan Zheng ◽  
Yousheng Zhang ◽  
Xin Yu
Keyword(s):  
Stainless Steel ◽  
Steady State ◽  
Detonation Wave ◽  
High Explosive ◽  
Numerical Study ◽  
Detonation Front ◽  
Outer Boundary ◽  
Outer Part ◽  
Transition Phase ◽  
Detonation Propagation

Detonation propagation in a confined circular arc configuration of an insensitive high explosive PBX9502 is investigated via numerical simulation in this paper. We introduce a steady detonation wave entering the explosive arc with confinements of stainless steel, and then it undergoes a transition phase and reaches a new steady state with a constant angular speed eventually. The influences of the inner and the outer confinements on the propagating detonation wave as well as the characteristics of the detonation driving zone (DDZ) in the steady state are discussed, respectively. Ignition and Growth (I&G) reaction rate and Jones–Wilkins–Lee (JWL) equations of state for the reactants and the products of PBX9502 are employed in the numerical simulations on the basis of a two-dimensional Eulerian code. The equation of state for stainless steel is in the Grüneisen form with a linear shock speed–particle speed Hugoniot relationship. Our results show that the inner confinement dominates the evolution of the detonation wave and the outer confinement only takes effect in a local region near the outer boundary within a limited initial stage during the transition phase. As for the steady state, the existence of the inner confinement makes the DDZ possess a certain width on the inner boundary. While as to the outer part of the detonation wave, the width of the DDZ decreases until the sonic locus intersects with the detonation front shock, which results in the detachment of the DDZ from the outer boundary and makes the detonation propagation fully independent of the outer confinement.

Optimal Design of a New Type of Savonius Rotor Using Simulation Analysis

2012 ◽  
Vol 499 ◽  
pp. 120-125 ◽  
Author(s):  
Zhi Peng Tang ◽  
Ying Xue Yao ◽  
Liang Zhou ◽  
Q. Yao
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Optimal Design ◽  
Simulation Analysis ◽  
Structural Parameters ◽  
Sliding Mesh ◽  
Savonius Rotor ◽  
Mesh Method ◽  
New Type

In order to enhance the efficiency of the Savonius rotor, this paper designs a new type of Savonius rotor with a rectifier. By using Computational Fluid Dynamics software to simulate and optimize the various parameters which affect the efficiency of the rotor. The sliding mesh method is applied here. The Cp-λ curves of wind turbine with different structural parameters are obtained after numerical simulation of flow field. On this basis, this paper gets the optimal structural parameters. And the results indicated that this new type of Savonius rotor has great improvement of efficiency compared with the traditional Savonius-type rotor.

Study of the Particle Separation Performance of a Dust-settling Hopper

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Bofu Wu ◽  
Jinlai Men ◽  
Jie Chen
Keyword(s):  
Fluid Dynamics ◽  
Particle Concentration ◽  
Separation Efficiency ◽  
Simulation Analysis ◽  
Numerical Study ◽  
Particle Separation ◽  
Separation Performance ◽  
Particle Removal ◽  
Airflow Velocity ◽  
Calculation Results

This paper presents a numerical study to predict the particle separation performance of a dust-settling hopper using computational fluid dynamics. The Euler-Lagrange approach was employed to analyze the particle separation efficiency and the outflow particle concentration of the dust-settling hopper under different inlet airflow velocities. The calculation results obtained reveal that the overall particle separation efficiency and the outflow particle concentration decrease with the increase of the inlet airflow velocity, and the particle grade efficiency increases with particle size. Since there is a paradox between the particle separation performance and the particle removal performance for a street vacuum sweeper, it is necessary to counter-balance the effects of the inlet airflow velocity on them. According to the simulation analysis, an appropriate inlet airflow velocity is provided for the design of the dust-settling hopper.

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