Analysis of perforation process into concrete/metal targets by rigid projectiles

2012 ◽  
Vol 227 (7) ◽  
pp. 1454-1468 ◽  
Author(s):  
N Khazraiyan ◽  
GH Liaghat ◽  
H Khodarahmi ◽  
N Dashtian-Gerami
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Cavity Expansion ◽  
Velocity Range ◽  
Material Models ◽  
Backing Plate ◽  
Expansion Theory ◽  
Cavity Expansion Theory ◽  
The Impact ◽  
Good Agreement

In this article, a semi-analytical model has been developed for perforation of a hard projectile into a single- and two-layer concrete targets. The model is based on the dynamic cavity expansion theory and the reflection of compressive waves from the end of the concrete targets. The effect of friction coefficient is also investigated in the analysis. Numerical modeling of the problem has been performed in LS-DYNA code. Holmquist–Johnson–Cook, plastic kinematic, and rigid material models have been employed for the concrete, the backing plate, and the projectile, respectively. The impact velocity range, considered in this study, is between 300 and 800 m/s. No projectile erosion is considered in this velocity range. The analytical results of the investigation for both single- and two-layer concrete targets are in a good agreement with numerical simulations and experimental data.

An Investigation on the Nose Mass Abrasion of Projectile

2013 ◽  
Vol 535-536 ◽  
pp. 449-452 ◽  
Author(s):  
Fei Qian ◽  
Hai Jun Wu ◽  
Feng Lei Huang ◽  
Yi Nan Wang
Keyword(s):  
Experimental Data ◽  
Impact Velocity ◽  
Spherical Cavity ◽  
Relative Strength ◽  
Cavity Expansion ◽  
Expansion Theory ◽  
Cavity Expansion Theory ◽  
Spherical Cavity Expansion

Based on the dynamic spherical cavity expansion theory of concrete and the analysis of experimental data, a mass abrasion model of projectile considering the hardness of aggregates, the relative strength of target and projectile and the initial impact velocity is constructed in this paper. The initial impact velocity is the most important factor of mass abrasion. The hardness of aggregates and the strength of projectile are also the significant factor of mass abrasion. But relatively speaking, the sensitivity of strength of projectile to mass abrasion is higher, which indicates that the effect of projectile material on mass abrasion is more dramatic than the hardness of aggregates.

The penetration and ricochet of ogive-nosed rigid projectiles obliquely impacting metallic targets

2021 ◽  
pp. 204141962110377
Author(s):  
Yaniv Vayig ◽  
Zvi Rosenberg
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Dynamic Pressure ◽  
Oblique Impacts ◽  
Simulation Results ◽  
The Impact ◽  
Penetration Depths ◽  
Resistance To Penetration ◽  
Good Agreement

A large number of 3D numerical simulations were performed in order to follow the trajectory changes of rigid CRH3 ogive-nosed projectiles, impacting semi-infinite metallic targets at various obliquities. These trajectory changes are shown to be related to the threshold ricochet angles of the projectile/target pairs. These threshold angles are the impact obliquities where the projectiles end up moving in a path parallel to the target’s face. They were found to depend on a non-dimensional entity which is equal to the ratio between the target’s resistance to penetration and the dynamic pressure exerted by the projectile upon impact. Good agreement was obtained by comparing simulation results for these trajectory changes with experimental data from several published works. In addition, numerically-based relations were derived for the penetration depths of these ogive-nosed projectiles at oblique impacts, which are shown to agree with the simulation results.

scholarly journals IDENTIFICATION AND VERIFICATION OF MATERIAL FUNCTIONS OF THE CREEP MODEL UNDER THERMAL RADIATION EFFECTS FOR AUSTENITIC STEEL 1X18H10T

2020 ◽  
Vol 82 (1) ◽  
pp. 89-99
Author(s):  
V.A. Gorokhov
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Creep Rate ◽  
Thermal Radiation ◽  
Neutron Irradiation ◽  
Radiation Effects ◽  
Thermal Creep ◽  
Creep Model ◽  
Material Functions ◽  
Good Agreement

In the present paper, on the basis of the information available in the scientific literature on the thermal creep rate of 1X18H10T austenitic steel under neutron irradiation conditions, the material functions of the thermal creep model implemented and verified in the framework of the certified software for numerical modeling of structural deformation under thermal and thermal radiation effects of UPAKS software are obtained and verified. The list of identifiable material functions of the thermal creep model includes: a function that characterizes the initial creep strain rate, referred to a unit stress level at a given temperature level and stress parameter; the radius of the creep surface, which is a function of temperature; the hardening function, characterizing the change in the initial creep rate from the hardening parameter at a given temperature; a function that takes into account the effect of a fast neutron flux on the creep rate at a given temperature. Using an analytical approximation of experimental data describing the rate of thermal creep of steels under neutron irradiation depending on the stresses, temperature, and flux of fast neutrons, we obtained relations for determining the values of all the functions of the thermal creep model. The value of the radius of the creep surface for a fixed temperature was determined from the condition that the creep deformation for a selected period of time and the neutron flux accumulated during this time will not exceed 0.2%. Using the UPAKS software, the creep model and the obtained material functions implemented in them, numerical simulation of the deformation of 1X18H10T steel under conditions of prolonged thermal load and neutron irradiation was performed. The results of numerical modeling are in good agreement with the analytical dependences that describe the creep of a given material under uniaxial SSS. A numerical creep simulation was also carried out under the assumption of the absence of neutron irradiation. As in the case of neutron irradiation, good agreement is obtained between the calculated and experimental data.

scholarly journals Study of the Impact of PV-Thermal and Nanofluids on the Desalination Process by Flashing

2020 ◽  
Vol 3 (1) ◽  
pp. 10
Author(s):  
Samuel Sami
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Solar System ◽  
Solar Radiation ◽  
Base Fluid ◽  
Control Volume ◽  
Proposed Model ◽  
Finite Control ◽  
The Impact ◽  
Mathematical And Numerical Modeling

In this study, a mathematical and numerical modeling of the photovoltaic (PV)-thermal solar system to power the multistage flashing chamber process is presented. The proposed model was established after the mass and energy conservation equations written for finite control volume were integrated with properties of the water and nanofluids. The nanofluids studied and presented herein are Ai2O3, CuO, Fe3O4, and SiO2. The multiple flashing chamber process was studied under various conditions, including different solar radiation levels, brine flows and concentrations, and nanofluid concentrations as well as flashing chamber temperatures and pressures. Solar radiation levels were taken as 500 w/m2, 750 w/m2, 1000 w/m2, and finally, 1200 w/m2. The nanofluid volumetric concentrations considered varied from 1% to 20%. There is clear evidence that the higher the solar radiation, the higher the flashed flow produced. The results also clearly show that irreversibility is reduced by using nanofluid Ai2O3 at higher concentrations of 10% to 20% compared to water as base fluid. The highest irreversibility was experienced when water was used as base fluid and the lowest irreversibility was associated with nanofluid SiO2. The irreversibility increase depends upon the type of nanofluid and its thermodynamic properties. Furthermore, the higher the concentration (e.g., from 10% to 20% of Ai2O3), the higher the availability at the last flashing chamber. However, the availability is progressively reduced at the last flashing chamber. Finally, the predicted results compare well with experimental data published in the literature.

Experimental and Numerical Investigation of Dynamic Impact on Universal Breakaway Steel Post

2019 ◽  
Author(s):  
Javad Mehrmashhadi ◽  
Mojdeh A. Pajouh ◽  
John D. Reid
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Numerical Model ◽  
Dynamic Impact ◽  
Roadside Safety ◽  
Impact Performance ◽  
Component Testing ◽  
Long Span ◽  
Finite Element Package ◽  
The Impact

Abstract A closed guardrail system, known as “bullnose” guardrail system, was previously developed to prevent out-of-control vehicles from falling into the elephant trap. The bullnose guardrail system originally used Controlled Release Terminal (CRT) wood posts to aid in the energy absorption of the system. However, the use of CRT had several drawbacks such as grading and the need for regular inspections. Universal Breakaway Steel Post (UBSP) was then developed by the researchers at Midwest Roadside Safety Facility as a surrogate for CRT. In this study, the impact performance of UBSP on the weak-axis and strong-axis was studied through numerical modeling and component testing (bogie testing). A numerical model was developed using an advanced finite element package LS-DYNA to simulate the impact on UBSP. The numerical results were compared to experimental data. Further research on soil models was recommended. The numerical model will be used to investigate other applications for UBSP such as the Midwest Guardrail System (MGS) long span system, guardrail end terminal designs, or crash cushions.

Comparison of Measured and Back Estimated Cone Penetration Resistance of Sand

2008 ◽  
Author(s):  
Meen-Wah Gui ◽  
Dong-Sheng Jeng
Keyword(s):  
Penetration Resistance ◽  
Cavity Expansion ◽  
Cone Penetration ◽  
Cone Penetration Tests ◽  
Cone Tip Resistance ◽  
Tip Resistance ◽  
Cone Penetration Resistance ◽  
Expansion Theory ◽  
Cavity Expansion Theory ◽  
Penetration Tests

The application of cavity expansion theory in the back estimation of cone penetration tests conducted in calibration chambers has been carried out by many researchers. However, the theory is seldom employed by centrifuge modelers. Based on the work of spherical cavity expansion of previous researchers, this study proposed an analytical solution that incorporates the effects of cone geometry and surface roughness and the effect of compressibility to estimate the cone tip resistance. The calculated results are compared with the measured cone penetration resistance of four cone penetration tests performed in the centrifuge. The cone penetration tests were conducted in granular soil specimens having relative densities ranging between 54% and 89%. The comparison demonstrates the capacity of the cavity expansion theory in the prediction of the centrifuge cone penetration resistance.

Empirical estimation of engine-integration noise for high bypass ra-tio turbofan engines

2021 ◽  
Vol 263 (2) ◽  
pp. 4511-4519
Author(s):  
Incheol Lee ◽  
Yingzhe Zhang ◽  
Dakai Lin
Keyword(s):  
Experimental Data ◽  
Pressure Side ◽  
Empirical Estimation ◽  
Low Frequencies ◽  
High Frequencies ◽  
Turbofan Engines ◽  
Proposed Model ◽  
The Impact ◽  
Bypass Ratio ◽  
Good Agreement

To investigate the impact of installation on jet noise from modern high-bypass-ratio turbofan engines, a model-scale noise experiment with a jet propulsion system and a fuselage model in scale was conducted in the anechoic wind tunnel of ONERA, CEPRA 19. Two area ratios (an area of the secondary nozzle over an area of the primary nozzle), 5 and 7, and various airframe configurations such as wing positions relative to the tip of the engine nacelle and flap angles, were considered. Based on the analysis of experimental data, an empirical model for the prediction of engine installation noise was proposed. The model comprises two components: one is the interaction be-tween the jet and the pressure side of the wing, and the other is the interaction between the jet and the flap tip. The interaction between the jet and the pressure side of the wing contributes to the noise at the low frequencies (≤ 1.5 kHz), and the interaction between the jet and the flap tip con-tributes to the noise at the high frequencies. The proposed model showed a good agreement with the experimental data.

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