scholarly journals Engineering Approximate Analysis Method of Rod Projectile Penetrating Concrete Target

2021 ◽  
Vol 283 ◽  
pp. 01014
Author(s):  
Wang Feng ◽  
Jiang Yaqiong ◽  
Ma Yurong ◽  
Li Dan ◽  
Zhou Wei
Keyword(s):  
Penetration Depth ◽  
Sliding Friction ◽  
Penetration Resistance ◽  
Analysis Method ◽  
Penetration Process ◽  
Penetration Ability ◽  
Analytical Formulas ◽  
Physical Quantities ◽  
Good Agreement ◽  
Concrete Target

The penetration process of rod projectile into concrete target is very complex, and the theoretical analysis is very difficult. In this paper, by using the engineering approximation method, through some reasonable simplification of the rod projectile penetration model, the analytical formulas of the penetration resistance, penetration depth and other important physical quantities are established. Through the calculation of penetration depth, when the sliding friction coefficient is 0.1, the results are in good agreement with the experimental results. The results show that the higher the projectile density and the sharper the shape of the warhead, the stronger the penetration ability.

The Numerical Simulation of Projectile Penetrating into Steel-Fiber Reinforced Ultra High Strength Concrete Target

2013 ◽  
Vol 357-360 ◽  
pp. 694-698
Author(s):  
Dan Li ◽  
Jun Lin Tao ◽  
Juan Tan
Keyword(s):  
Steel Fiber ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Penetration Process ◽  
Explicit Finite Element ◽  
Reactive Powder ◽  
Good Agreement ◽  
Concrete Target

Explicit finite element code was applied to simulate the steel fiber reinforced concrete (SFRC) and reactive powder concrete (RPC) target penetrated by kinetic energy projectile. Crater formation, spall of concrete target in penetration process was simulated very well. The numerical results of penetration depths are in good agreement with recent experimental results obtained from ballistic gun with 57mm caliber. The factors effecting on anti-penetration property of SFRC and RPC are analyzed. The results show that: the compressive strength and toughness of the target body have greater impact on anti-penetration performance in the range of projectile velocity 300m/s-600m/s. Anti-penetration capability of RPC concrete is stronger than that of ordinary steel fiber at the higher speeds.

The Approximate Analytical Solution of the MHD Flow of a Power-Law Fluid

2013 ◽  
Vol 431 ◽  
pp. 198-201
Author(s):  
Jing Zhu ◽  
Lian Cun Zheng
Keyword(s):  
Differential Equations ◽  
Power Law ◽  
Velocity Ratio ◽  
Mhd Flow ◽  
Convergent Series ◽  
Analysis Method ◽  
Governing System ◽  
Homotopy Analysis ◽  
Incompressible Mhd ◽  
Good Agreement

This paper presents a theoretical analysis for the incompressible MHD stagnation-point flows of a Non-Newtonian Fluid over stretching sheets.The governing system of partial differential equations is first transformed into a system of dimensionless ordinary differential equations. By using the homotopy analysis method, a convergent series solution is obtained. The reliability and efficiency of series solutions are illustrated by good agreement with numerical results in the literature.Besides, the effects of the power-law indexthe magnetic field parameter and velocity ratio parameter on the flow are investigated.

NMR Technique for Multiphase Fluid Study Involving Melting Phenomena

1999 ◽  
Author(s):  
Q. Ni ◽  
J. D. King ◽  
Y.-X. Tao
Keyword(s):  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Melting Rate ◽  
Analysis Method ◽  
Image Analysis Method ◽  
Equilibrium Conditions ◽  
Multiphase Fluid ◽  
Physical Phenomena ◽  
Non Destructive ◽  
Good Agreement

Abstract Nuclear magnetic resonance (NMR) sensors are used to determine the time variation of solid mass for a packed ice bed in an experiment of convective melting under non-thermal equilibrium conditions. The paper describes the basic experimental technique for NAFTM apparatus and feasibility for determining the solid volume fraction and ultimately the melting rate. The NMR technique provides an effective, non-destructive method for multiphase fluid study where phase change is one of the important physical phenomena. The results show a good agreement of data obtained by the NMR method with those from image-analysis method.

scholarly journals Homotopy Analysis Solution for Magnetohydrodynamic Squeezing Flow in Porous Medium

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Inayat Ullah ◽  
M. T. Rahim ◽  
Hamid Khan ◽  
Mubashir Qayyum
Keyword(s):  
Porous Medium ◽  
Control Parameter ◽  
Analytical Techniques ◽  
Squeezing Flow ◽  
Analysis Method ◽  
Homotopy Analysis ◽  
Convergence Control ◽  
Flow Through ◽  
Convergence Control Parameter ◽  
Good Agreement

The aim of the present work is to analyze the magnetohydrodynamic (MHD) squeezing flow through porous medium using homotopy analysis method (HAM). Fourth-order boundary value problem is modeled through stream functionψ(r,z)and transformationψ(r,z)=r2f(z). Absolute residuals are used to check the efficiency and consistency of HAM. Other analytical techniques are compared with the present work. It is shown that results of good agreement can be obtained by choosing a suitable value of convergence control parameterhin the valid regionRh. The influence of different parameters on the flow is argued theoretically as well as graphically.

scholarly journals A Useful Manufacturing Guide for Rotary Piercing Seamless Pipe by ALE Method

2020 ◽  
Vol 8 (10) ◽  
pp. 756
Author(s):  
Ameen Topa ◽  
Burak Can Cerik ◽  
Do Kyun Kim
Keyword(s):  
Numerical Simulations ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Material Model ◽  
Manufacturing Processes ◽  
Arbitrary Lagrangian Eulerian ◽  
Analysis Method ◽  
Seamless Pipe ◽  
Ale Formulation ◽  
Good Agreement

The development of numerical simulations is potentially useful in predicting the most suitable manufacturing processes and ultimately improving product quality. Seamless pipes are manufactured by a rotary piercing process in which round billets (workpiece) are fed between two rolls and pierced by a stationary plug. During this process, the material undergoes severe deformation which renders it impractical to be modelled and analysed with conventional finite element methods. In this paper, three-dimensional numerical simulations of the piercing process are performed with an arbitrary Lagrangian–Eulerian (ALE) formulation in LS-DYNA software. Details about the material model as well as the elements’ formulations are elaborated here, and mesh sensitivity analysis was performed. The results of the numerical simulations are in good agreement with experimental data found in the literature and the validity of the analysis method is confirmed. The effects of varying workpiece velocity, process temperature, and wall thickness on the maximum stress levels of the product material/pipes are investigated by performing simulations of sixty scenarios. Three-dimensional surface plots are generated which can be utilized to predict the maximum stress value at any given combination of the three parameters.

Dynamic Characteristics of TEHD Tilt Pad Journal Bearing Simulation Including Multiple Mode Pad Flexibility Model

1993 ◽  
Author(s):  
Jinsang Kim ◽  
Alan Palazzolo
Keyword(s):  
Heat Transfer ◽  
Elastic Deformation ◽  
Degrees Of Freedom ◽  
Journal Bearing ◽  
Variable Viscosity ◽  
Global Analysis ◽  
Analysis Method ◽  
Stiffness And Damping ◽  
Modal Coordinates ◽  
Good Agreement

Abstract An approach for incorporating the heat transfer and elastic deformation effects into dynamic coefficient calculation is presented. A global analysis method is used, which finds the equilibrium pad tilt angles at each eccentricity position and includes cross-film variable viscosity, heat transfer effects in the lubricant, elastic deformation, heat conduction effects in the pads, and elastic deformation effect in the pivots. Deflection modes are used to approximate deformation of the top surface of the pads. The dynamic coefficients of a single pad are calculated at the equilibrium state of the bearing, based on numerical perturbation with respect to the bearing degrees of freedom. These include journal position, pad rotation, pivot deformation, and modal coordinates. The stiffness and damping coefficients are calculated and show very good agreement with experimental and numerical results from the existing literature.

scholarly journals LOWER CRITICAL MAGNETIC FIELD OF SUPERCONDUCTING Rb3C60

1992 ◽  
Vol 06 (16n17) ◽  
pp. 1037-1042 ◽  
Author(s):  
V. BUNTAR ◽  
U. ECKERN ◽  
C. POLITIS
Keyword(s):  
Magnetic Field ◽  
Penetration Depth ◽  
High Field ◽  
Model Analysis ◽  
Critical Magnetic Field ◽  
Field Analysis ◽  
Zero Temperature ◽  
Bean Model ◽  
Good Agreement

The lower critical magnetic field Hc1 of superconducting Rb 3 C 60 (Tc=28.5 K ) is estimated by different methods. The zero temperature value is found to be given by Hc1=16.2±1.0 mT, and the penetration depth is λL=215±10 nm . The Bean model analysis leads to threshold fields of 5.3 mT for T=5 K , and 4.0 mT for T=17 K . The big influence of intergranular connections on Hc1 is demonstrated. Good agreement between the low- and the high-field analysis is found.

Free Vibrations of Beams on Viscoelastic Pasternak Foundations

2015 ◽  
Vol 744-746 ◽  
pp. 1624-1627
Author(s):  
Li Peng ◽  
Ying Wang
Keyword(s):  
Natural Frequencies ◽  
Free Vibrations ◽  
Mode Analysis ◽  
Analysis Method ◽  
Governing Equations ◽  
Complex Mode ◽  
Transverse Vibrations ◽  
Quadrature Methods ◽  
Foundation Parameters ◽  
Good Agreement

This paper investigates free transverse vibrations of finite Euler–Bernoulli beams resting on viscoelastic Pasternak foundations. The differential quadrature methods (DQ) are applied directly to the governing equations of the free vibrations. Under the simple supported boundary condition, the natural frequencies of the transverse vibrations are calculated, and compared with the results of the complex mode analysis method. The numerical results obtained by using the DQ and the complex mode methods are in good agreement for the first seven order natural frequencies, but with the growth of the orders, the small quantitative differences between them increase. The effects of the foundation parameters on the natural frequencies are also studied in numerical examples.

The Study on a New Approximate Method of Computing Electromagnetic Scattering from Multilayer Rough Sea Surfaces

2014 ◽  
Vol 533 ◽  
pp. 268-273
Author(s):  
Jia Sheng Tian ◽  
Wan Pan ◽  
Jian Shi
Keyword(s):  
Electromagnetic Scattering ◽  
Computation Time ◽  
Sea Surface ◽  
Analysis Method ◽  
Large Matrix ◽  
Random Rough Surfaces ◽  
Strong Winds ◽  
Rough Sea Surface ◽  
Rough Sea ◽  
Good Agreement

At high sea states strong winds make the sea surface broken, and become a multilayer-rough sea surface made of a large number of foams and droplets. Similarly, if the sea surface covered by oil and other dirts will also belong to the mutilayer rough sea surfaces of various medium properties. In this paper, applying the Kirchhoff Approximation (KA) and the electromagnetic theory of stratified media, electromagnetic scattering characteristics from a multilayer rough medium surface are calculated. Firstly, a detailed analysis of electromagnetic reflection from multilayer parallel interfaces under different incident angles is carried out. Secondly, combining the preceding two results and courses, electromagnetic scattering from the multilayer random rough surfaces is studied. The computed results are in good agreement with those by using the method of moments (MOM) and reported by some experts. Finally, the random rough sea surface covered by spilling oil or droplets and foams is calculated in detail. Compared with MOM, the new approximate analysis method in the paper can avoid a large matrix inversion, and thus greatly reduce the computation time and improve the computational efficiency.

A Shortcut Fatigue Analysis Method

1990 ◽  
Vol 112 (1) ◽  
pp. 1-5 ◽  
Author(s):  
H. M. Thompson
Keyword(s):  
Fatigue Life ◽  
Transfer Function ◽  
Fatigue Analysis ◽  
Analysis Method ◽  
Dynamic Amplification Factor ◽  
Single Degree Of Freedom ◽  
At Resonance ◽  
Order Of Magnitude ◽  
Dynamic Amplification ◽  
Good Agreement

A shortcut fatigue analysis method is presented which can be used to provide fatigue life estimates during the preliminary design phase of deepwater fixed platforms. For this type of structure, the method is intended to provide order of magnitude fatigue life estimates only. For simpler structures, such as deepwater offshore caissons, the shortcut analysis can provide good agreement with a detailed spectral fatigue analysis. The fundamental assumption of the method is that the dynamic transfer function can be closely approximated by the product of the static transfer function and a single degree of freedom dynamic amplification factor, which has been adjusted to produce a “fit” to the true DAF at resonance. Only one dynamic analysis of the structure needs to be performed, i.e., to determine the true DAF at resonance.

Sign in / Sign up

Export Citation Format

Share Document