scholarly journals Numerical Simulation of Rod Jet Formed by Shaped Charge under Rigid Constraint

2022 ◽  
Vol 2160 (1) ◽  
pp. 012040
Author(s):  
Kai Chen ◽  
Shuyou Wang ◽  
Yawei Wang ◽  
Ze Shi
Keyword(s):  
Wall Thickness ◽  
Structural Parameters ◽  
Shaped Charge ◽  
Central Position ◽  
Curvature Radius ◽  
Variable Ratio ◽  
Rigid Boundary ◽  
Head Velocity ◽  
Finite Element Software ◽  
Boundary Constraint

Abstract In order to study the forming law of rod jet formed by shaped charge under rigid boundary constraint, ANSYS/LSDYNA finite element software is used to simulate the forming process of rod jet with ALE essential boundary, and the influence of structural parameters of shaped charge on rod jet forming is studied. The results show that compared with the free boundary constraint, the head velocity of rod jet increases by 63.5 % and the tail velocity increases by 59.3 % under the rigid boundary constraint. The head velocity and length-diameter ratio of rod jet decrease with the increase of the outside curvature radius of the liner, the thickness of the liner central position and the variable ratio of wall thickness. Furthermore, the tail velocity increases with the increase of the outside curvature radius of the liner, and decreases with the increase of the thickness of the liner central position and the variable ratio of wall thickness.

scholarly journals Study of the Forming Characteristics of Small-Caliber Ammunition with Circumferential MEFP

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 891 ◽  
Author(s):  
Guangsong Ma ◽  
Guanglin He ◽  
Yukuan Liu ◽  
Yachao Guo
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Structural Parameters ◽  
Outer Wall ◽  
Diameter Ratio ◽  
Curvature Radius ◽  
Preliminary Design ◽  
Finite Element Software ◽  
Forming Characteristics ◽  
Simulation Results

To study the influence of the structural parameters of the ammunition liner of small-caliber ammunition on the forming characteristics of the projectile, an integrated circumferential multiple explosively formed projectile (MEFP) warhead with an integrated shell and the liner was initially designed, and the wall thickness of the liner is variable. LS-DYNA finite-element software is used to simulate the integral circumferential MEFP of the preliminary design, based on the numerical simulation results, the influence of the thickness at the center of the liner, and the curvature radius of the liner on the shape and velocity of the formed projectile. The numerical simulation results show that when the thickness of the center of the liner is constant and the curvature radius increases gradually, the velocity of the formed projectile decreases and the length: Diameter ratio of formed projectile decreases gradually. When the curvature radius of the liner remains unchanged, the velocity of the formed projectile decreases with the increase of the thickness of the center of the liner, and the shape of the formed projectile does not change significantly. The results show that when the design of integrating the shell and the liner was adopted for the integral circumferential MEFP warhead, the shape of the formed projectile is greatly affected by the curvature radius of the liner (curvature radius of inner and outer walls of the liner), but less by the thickness of the center of the liner. The velocity of the formed projectile is affected by the curvature radius of the inner and outer walls of the liner and the thickness of the center of the liner. Moreover, the influence of the thickness of the center of the liner on the velocity of the formed projectile is greater than that of the curvature radius of the outer wall of the liner.

Numerical Simulation of a Circumferential Cutting Warhead about Anti-Light Armor

2013 ◽  
Vol 706-708 ◽  
pp. 1454-1457
Author(s):  
Yong Jie Xu ◽  
Guo Dong Wu ◽  
Shao Lei Liang ◽  
Zhi Jun Wang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Formation Process ◽  
Shaped Charge ◽  
Curvature Radius ◽  
Finite Element Software ◽  
Damage Probability ◽  
Optimization Simulation ◽  
New Type ◽  
Block Area

In order to improve the block area and damage probability to targets, a new type warhead of circumferential cutter is presented. The optimization simulation is designed for the circumferential cutter warhead by using LS-DYNA finite element software. The detonation mode and the liner curvature radius are two important factors, which influence the formation process of circumferential cutting warhead. The result shows that priority should be given to use the upper and lower ends at the same time blasting technique. The shaped charge liner curvature radius and shot elevation ratio should be controlled in between 0.9 and 1.1.The warhead can be envisaged to achieve the desire of circumferential cutting.

scholarly journals Research and Fabrication of Broadband Ring Flextensional Underwater Transducer

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1548
Author(s):  
Jiuling Hu ◽  
Lianjin Hong ◽  
Lili Yin ◽  
Yu Lan ◽  
Hao Sun ◽  
...  
Keyword(s):  
High Speed ◽  
Structural Parameters ◽  
Low Frequency ◽  
Flexural Vibration ◽  
Underwater Acoustic Communication ◽  
Voltage Response ◽  
Water Tank ◽  
Spherical Cap ◽  
Finite Element Software ◽  
Underwater Transducer

At present, high-speed underwater acoustic communication requires underwater transducers with the characteristics of low frequency and broadband. The low-frequency transducers also are expected to be low-frequency directional for realization of point-to-point communication. In order to achieve the above targets, this paper proposes a new type of flextensional transducer which is constructed of double mosaic piezoelectric ceramic rings and spherical cap metal shells. The transducer realizes broadband transmission by means of the coupling between radial vibration of the piezoelectric rings and high-order flexural vibration of the spherical cap metal shells. The low-frequency directional transmission of the transducer is realized by using excitation signals with different amplitude and phase on two mosaic piezoelectric rings. The relationship between transmitting voltage response (TVR), resonance frequency and structural parameters of the transducer is analyzed by finite element software COMSOL. The broadband performance of the transducer is also optimized. On this basis, the low-frequency directivity of the transducer is further analyzed and the ratio of the excitation signals of the two piezoelectric rings is obtained. Finally, a prototype of the broadband ring flextensional underwater transducer is fabricated according to the results of simulation. The electroacoustic performance of the transducer is tested in an anechoic water tank. Experimental results show that the maximum TVR of the transducer is 147.2 dB and the operation bandwidth is 1.5–4 kHz, which means that the transducer has good low-frequency, broadband transmission capability. Meanwhile, cardioid directivity is obtained at 1.4 kHz and low-frequency directivity is realized.

CLASSIFICATION OF BUCKLING MODES IN STIFFENED FUNCTIONALLY GRADED COMPOSITE TUBES SUBJECT TO BENDING

2021 ◽  
Author(s):  
LUAN TRINH ◽  
PAUL WEAVER
Keyword(s):  
Wall Thickness ◽  
Functionally Graded ◽  
Geometric Parameters ◽  
Mode Shapes ◽  
Local Mode ◽  
Buckling Mode ◽  
Global Mode ◽  
Local Modes ◽  
Linear Discriminant ◽  
Finite Element Software

Bamboo poles, and other one-dimensional thin-walled structures are usually loaded under compression, which may also be subject to bending arising from eccentric loading. Many of these structures contain diaphragms or circumferential stiffeners to prevent cross-sectional distortions and so enhance overall load-carrying response. Such hierarchical structures can compartmentalize buckling to local regions in addition to withstanding global buckling phenomena. Predicting the buckling mode shapes of such structures for a range of geometric parameters is challenging due to the interaction of these global and local modes. Abaqus finite element software is used to model thousands of circular hollow tubes with random geometric parameters such that the ratios of radius to periodic length range from 1/3-1/7, the ratio of wall thickness to radius varies from 1/4-1/10. The material used in this study is a type of bamboo, where the Young’s and shear moduli are point-wise orthotropic and gradually increase in magnitude in the radial direction. Under eccentric loads with varying eccentricity, the structures can buckle into a global mode or local modes within an internode, i.e. periodic unit. Moreover, the local modes may contain only one wave or multiple waves in the circumferential direction. As expected, numerical results show that the global mode is more likely to occur in small and thick tubes, whereas the local modes are observed in larger tubes with a smaller number of circumferential waves present in thicker walls. Also, greater eccentricity pushes the local mode domains towards smaller tubes. An efficient classification method is developed herein to identify the domains of each mode shape in terms of radius, wall thickness and eccentricity. Based on linear discriminant analysis, explicit boundary surfaces for the three domains are defined for the obtained data, which can help designers in predicting the mode shapes of tubular structures under axial bending.

scholarly journals Sub-impacts of simply supported beam struck by steel sphere—part II: Numerical simulations

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668335
Author(s):  
Xiaoli Qi ◽  
Xiaochun Yin
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Great Influence ◽  
Element Model ◽  
Theoretical Expression ◽  
Curvature Radius ◽  
Steel Sphere ◽  
Impact Time ◽  
Finite Element Software ◽  
Contact Impact

This part of the article describes numerical simulations of the problem investigated experimentally. A three-dimensional finite element model of elastic–plastic for sphere falling on beam has been implemented using the nonlinear dynamic finite element software LS-DYNA. From the numerical simulations, it was found that the LS-DYNA is suitable to study complex sub-impact phenomenon, and good agreement is in general obtained between the simulation and experimental results. The numerical simulations show that the initial impact velocity, equivalent elasticity modulus, contact curvature radius of the sphere, and equivalent mass have great influence on the contact–impact time of the sub-impact, and an applicable range of the theoretical expression of contact–impact time of the sub-impact was determined. In addition, the numerical simulations demonstrate the ratios of maximum amplitudes of the first-, second-, and third-order vibrations to the maximum amplitudes of the beam vibrations, and the phase angle of the first-order vibration will change suddenly when the sub-impacts occur. Furthermore, the occurrence conditions of the sub-impacts were clarified numerically. It was found that the occurrence conditions of the sub-impacts can be represented by a mass ratio threshold, and the thickness or length of the beam has also a great influence on the occurrence of the sub-impacts. Once the sub-impacts occur, which would result in an uncertain behavior of the apparent coefficient of restitution.

Analyzing of Dynamic Characteristics of Special CNC Machine Tool

2010 ◽  
Vol 29-32 ◽  
pp. 2037-2041
Author(s):  
Ke Wang ◽  
Guang Lv ◽  
Xing Wei Sun
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Optimization Design ◽  
High Efficiency ◽  
Structural Parameters ◽  
Force Frequency ◽  
Cutting Method ◽  
Finite Element Software ◽  
Exciting Frequency ◽  
Motion Parameters

The dynamic characteristics of machine tool is an important factor, which make affect on the cutting stability of machine tool. The poor dynamic characteristics will seriously affect the stability of cutting, make the low cutting efficiency and low machining precision, and also accelerate the wear of tools and even reduce the machine’s service life. So it is necessary to analyze the dynamic characteristics of machine tool, and according to the results of analysis to optimize structural parameters and motion parameters of the machine tools. This paper analyses the dynamic characteristics of machine bed and machined work piece of the CNC special machine tool for Kelly with the finite element software, and analysis of excitation characteristics of cutting tool. It also makes optimization design to the machine bed, through the analysis and optimization, the natural frequency and stiffness will be obviously improved. According to the structure and calculation of the motion parameters we can get the exciting force frequency to workpiece when it is cut, using interlocking tooth cutting method to replace the initial symmetrical cutting method in order to avoid the resonance produced in the cutting process and improve stability. The exciting frequency when cutting can be improved and the probability of resonance when cutting is lowered. All these ensure high efficiency and high stability cutting.

scholarly journals Optimal design for outer rings of self-lubricating spherical plain bearings based on virtual orthogonal experiments

2018 ◽  
Vol 10 (6) ◽  
pp. 168781401878340
Author(s):  
Lingzhu Gong ◽  
Xiaoxiang Yang ◽  
Kaibin Kong ◽  
Shuncong Zhong
Keyword(s):  
Structural Parameters ◽  
Equivalent Plastic Strain ◽  
Outer Ring ◽  
Forming Process ◽  
Finite Element Software ◽  
Orthogonal Experiments ◽  
Balance Analysis ◽  
New Type ◽  
End Wall

To improve the product quality of self-lubricating spherical plain bearing, a new shape of the outer rings for spherical plain bearings was optimally designed based on virtual orthogonal experiments using finite element software ABAQUS. The depth inclined end wall, together with the length of annular wall, the depth of annular concavity, the outer ring thickness, and the edge radius were taken as the main structural parameters in the analysis. For the evaluation parameters, the maximum bearing clearance, the maximum contact pressure, the maximum extrusion load, and the maximum equivalent plastic strain were considered. The optimal structure parameter combination was identified based on the intuitive comprehensive balance analysis method. The simulation results demonstrated much improvement for the forming quality by using a new type of the outer ring, which was optimized by the virtual orthogonal experiments. The new type of the outer ring could be used to the forming process in assembling the spherical plain bearings.

Study on Three-Way Pipe’s Internal High Pressure Forming Simulation

2013 ◽  
Vol 589-590 ◽  
pp. 517-522
Author(s):  
Shi Gang Wang ◽  
Fu Sheng Gao ◽  
Feng Lan Cheng ◽  
Qiang Guo
Keyword(s):  
High Pressure ◽  
Wall Thickness ◽  
Three Dimensional ◽  
Thickness Variation ◽  
Forming Simulation ◽  
Finite Element Software ◽  
Plastic Processing ◽  
Wall Thickness Variation ◽  
Dimensional Shape ◽  
Pressure Parameter

Internal high pressure forming is a kind of the modern plastic processing technology. Using liquid as the pressure transmitting medium, explore the effect of internal high pressure parameter on the three passing pipe technique, internal high pressure forming technique is applied on the three-dimensional shape parts deformation. In this study, we simulate the three-way pipe process by finite element software, analyze the forming force influence to the tube forming quality and get the changeable regulation of the pipe wall thickness with conclusion of the wall thickness variation, which provides the reference data and guidance for the actual production of the three-way pipe.

Seismic Response Analysis of Twin-Tower Building with Enlarged Base

2014 ◽  
Vol 912-914 ◽  
pp. 1534-1537
Author(s):  
Shao Bo Zhang ◽  
Ke Lun Wei ◽  
Bi Jian Xiao
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Boundary Conditions ◽  
Seismic Response ◽  
Time History ◽  
Response Analysis ◽  
Rigid Boundary ◽  
Finite Element Software ◽  
Elastic Boundary ◽  
Elastic Boundary Conditions

This paper adopts large finite element software ANSYS to establish finite element model of twin-tower building with enlarged base, uses dynamic time history analysis method for seismic response calculation, compare and analyze the calculation results of twin-tower building with enlarged base under elastic boundary conditions and rigid boundary conditions. The results showe that dynamic response for model under elastic boundary conditions is larger than dynamic response for model under rigid boundary conditions, and elastic boundary conditions is more close to the actual situation.

Optimization Dressing Method of Amplitude Transformer Based on Finite Element

2013 ◽  
Vol 278-280 ◽  
pp. 315-318
Author(s):  
Ming Li Zhao ◽  
Bo Zhao ◽  
Yu Qing Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Resonant Frequency ◽  
Structural Parameters ◽  
Low Cost ◽  
Dressing Method ◽  
Finite Element Software ◽  
System Vibration ◽  
Vibration Performance ◽  
Element Method

The node position of amplitude transformer was determined by the finite element method, and the flange was designed at the nod position for conveniently installation. By the finite element software, the amplitude transformer with flange was optimized and dressed, and its structural parameters were determined. During the actual manufacturing process, it was used impedance analyzer to test its vibration performance, the testing results show that this system vibration performance is good, its resonant frequency is 34.771kHz, anti-resonant frequency is 35.008kHz. The above-mentioned results are very much coincided with the system natural frequency of 34.893kHz which is drew by finite element method. Compared to the traditional dressing this method has many advantages such as convenience, green, environmental protection, low cost and others.

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