Investigation on penetration model of shaped charge jet in water

2016 ◽  
Vol 30 (02) ◽  
pp. 1550268 ◽  
Author(s):  
Jinwei Shi ◽  
Xingbai Luo ◽  
Jinming Li ◽  
Jianwei Jiang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Model ◽  
Model Simulation ◽  
Theoretical Models ◽  
Theoretical Research ◽  
Water Medium ◽  
Simulation Results ◽  
Jet Penetration ◽  
The Impact ◽  
Penetration Velocity

To analyze the process of jet penetration in water medium quantitatively, the properties of jet penetration spaced target with water interlayer were studied through test and numerical simulation. Two theoretical models of jet penetration in water were proposed. The theoretical model 1 was established considering the impact of the shock wave, combined with the shock equation Rankine–Hugoniot and the virtual origin calculation method. The theoretical model 2 was obtained by fitting theoretical analysis and numerical simulation results. The effectiveness and universality of the two theoretical models were compared through the numerical simulation results. Both the models can reflect the relationship between the penetration velocity and the penetration distance in water well, and both the deviation and stability of theoretical model 1 are better than 2, the lower penetration velocity, and the larger deviation of the theoretical model 2. Therefore, the theoretical model 1 can reflect the properties of jet penetration in water effectively, and provide the reference of model simulation and theoretical research.

Numerical Modeling of Multi-Frequency Complex Dielectric Permittivity Dispersion of Sedimentary Rocks

Geophysics ◽  
2021 ◽  
pp. 1-69
Author(s):  
Artur Posenato Garcia ◽  
Zoya Heidari
Keyword(s):  
Numerical Simulation ◽  
Dielectric Permittivity ◽  
Numerical Simulations ◽  
Dielectric Response ◽  
Water Saturation ◽  
Pore Scale ◽  
Simulation Results ◽  
Wet Rocks ◽  
Permittivity Measurements ◽  
The Impact

The dielectric response of rocks results from electric double layer (EDL), Maxwell-Wagner (MW), and dipolar polarizations. The EDL polarization is a function of solid-fluid interfaces, pore water, and pore geometry. MW and dipolar polarizations are functions of charge accumulation at the interface between materials with contrasting impedances and the volumetric concentration of its constituents, respectively. However, conventional interpretation of dielectric measurements only accounts for volumetric concentrations of rock components and their permittivities, not interfacial properties such as wettability. Numerical simulations of dielectric response of rocks provides an ideal framework to quantify the impact of wettability and water saturation ( Sw) on electric polarization mechanisms. Therefore, in this paper we introduce a numerical simulation method to compute pore-scale dielectric dispersion effects in the interval from 100 Hz to 1 GHz including impacts of pore structure, Sw, and wettability on permittivity measurements. We solve the quasi-electrostatic Maxwell's equations in three-dimensional (3D) pore-scale rock images in the frequency domain using the finite volume method. Then, we verify simulation results for a spherical material by comparing with the corresponding analytical solution. Additionally, we introduce a technique to incorporate α-polarization to the simulation and we verify it by comparing pore-scale simulation results to experimental measurements on a Berea sandstone sample. Finally, we quantify the impact of Sw and wettability on broadband dielectric permittivity measurements through pore-scale numerical simulations. The numerical simulation results show that mixed-wet rocks are more sensitive than water-wet rocks to changes in Sw at sub-MHz frequencies. Furthermore, permittivity and conductivity of mixed-wet rocks have weaker and stronger dispersive behaviors, respectively, when compared to water-wet rocks. Finally, numerical simulations indicate that conductivity of mixed-wet rocks can vary by three orders of magnitude from 100 Hz to 1 GHz. Therefore, Archie’s equation calibrated at the wrong frequency could lead to water saturation errors of 73%.

Influence of Engine Cabin Simplification on Aerodynamic Characteristics of Car

2014 ◽  
Vol 1042 ◽  
pp. 188-193 ◽  
Author(s):  
Xing Jun Hu ◽  
Jing Chang
Keyword(s):  
Numerical Simulation ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
Thin Plates ◽  
Average Thickness ◽  
Two Dimensional ◽  
Engine Cooling ◽  
Aerodynamic Drag Coefficient ◽  
Simulation Results ◽  
The Impact

In order to analyze the impact of engine cabin parts on aerodynamic characteristics, the related parts are divided into three categories except the engine cooling components: front thin plates (average thickness of 2mm), bottom-suspension and interior panels. The aerodynamic drag coefficient (Cd) were obtained upon the combination schemes consisting of the three types of parts by numerical simulation. Results show that Cd by simulation is closer to the test value gained by the wind tunnel experiment when front thin plates were simplified to the two-dimensional interface with zero thickness. The error is only 5.23%. Meanwhile this scheme reduces grid numbers, thus decreasing the calculating time. As the front thin plates can guide the flow, there is no difference on the Cd values gained from the model with or without bottom-suspension or interior panels when the engine cabin contains the front thin plates; while only both bottom-suspension and interior panels are removed, the Cd value can be reduced when the cabin doesn’t contain the front thin plates.

Numerical Simulation and Analysis on the Impact Effect of Cylindrical Projectile Impacting Shelled Explosive

2013 ◽  
Vol 710 ◽  
pp. 320-324
Author(s):  
Ying Zi Jiang ◽  
Wei Li Wang ◽  
Xue Feng Huang ◽  
Lei Fu ◽  
Zhuang Qing Fan
Keyword(s):  
Numerical Simulation ◽  
Energy Criterion ◽  
Critical Energy ◽  
Simplified Model ◽  
Initiation Point ◽  
4340 Steel ◽  
Simulation Results ◽  
The Impact ◽  
Explosive Detonation ◽  
Critical Initiation

The numerical simulation of shelled Comp.B explosive was studied following the Lee-Tarver ignition and growth model when it was impacted respectively by 4340 Steel, OFHC and 93#W projectile with the same mass; the influences on explosive detonation of the initiation process, the material of projectile and the L/D ratio of projectile were analyzed; the critical initiation speeds of the projectiles of three different materials with different L/D ratio were gained. In order to verify the simulation results, the questions were calculated by the theoretical simplified model, the results of the theoretical calculation and the numerical simulation accorded well based on critical energy criterion. The results show that the capability of igniting explosive, the first is 93#W, the second is OFHC, the last is 4340 Steel; The initiation point were not on the interface of shell and explosive, and the faster of the impacting velocity, the initiation point closer the interface; the bigger of the L/D ratio of projectile, the higher of the critical initiation speed.

The Numerical Simulation of Effective Elastic Response for WC-Co Cemented Carbide

2015 ◽  
Vol 1096 ◽  
pp. 417-421
Author(s):  
Pei Luan Li ◽  
Zi Qian Huang
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Theoretical Model ◽  
Material Properties ◽  
Cemented Carbide ◽  
Elastic Response ◽  
The Finite Element Method ◽  
Simulation Results ◽  
Element Method

By the use of finite element method, this paper predicts the effects of the shapes of reinforcements with different ductility (Co) on the effective elastic response for WC-Co cemented carbide. This paper conducts a comparative study on the material properties obtained through theoretical model, numerical simulation and experimental observations. Simulation results indicate that the finite element method is more sophisticated than the theoretical prediction.

scholarly journals Experimental Research and Numerical Simulation on Grouting Quality of Shield Tunnel Based on Impact Echo Method

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Fei Yao ◽  
Guangyu Chen ◽  
Jianhong Su
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Working Conditions ◽  
Acoustic Impedance ◽  
Shield Tunnel ◽  
Test Results ◽  
Impact Echo ◽  
Simulation Results ◽  
The Impact ◽  
Impact Echo Method

To identify shield grouting quality based on impact echo method, an impact echo test of segment-grouting (SG) test piece was carried out to explore effect of acoustic impedance of grouting layers and grouting defects on impact echo law. A finite element numerical simulation on the impact echo process was implemented. Test results and simulation results were compared. Results demonstrated that, under some working conditions, finite element simulation results and test results both agree with theoretical values. The acoustic impedance ratio of SG material influenced the echo characteristics significantly. But thickness frequency could not be detected under some working conditions because the reflected energy is weak. Frequency feature under grouting defects was more complicated than that under no grouting defects.

The impact of nostalgic emotion on brand trust and brand attachment

2019 ◽  
Vol 31 (4) ◽  
pp. 1118-1137 ◽  
Author(s):  
Tao Wen ◽  
Tong Qin ◽  
Raymond R. Liu
Keyword(s):  
Theoretical Model ◽  
Positive Impact ◽  
Service Industries ◽  
Theoretical Research ◽  
Brand Trust ◽  
Brand Attachment ◽  
Content Type ◽  
Four Dimensions ◽  
Potential Applicability ◽  
The Impact

Purpose The purpose of this paper is to make up the deficiency of theoretical research in nostalgic marketing and is helpful for the original theories of brand marketing and experiential marketing to deepen further. Design/methodology/approach The paper uses the approach of the empirical study. Based on the literature review, a theoretical model of the impact of nostalgic emotion (NE) on brand trust and brand attachment is constructed and corresponding research hypotheses are proposed. Then nostalgia-themed restaurants are selected to complete a questionnaire survey, and SPSS22.0 and LISREL8.70 are used for data analysis and hypothesis testing. Findings The results of the paper show that NE consists of four dimensions in the context of China: atmosphere nostalgia, interpersonal nostalgia, family nostalgia and personal nostalgia. Among these, NE has a significant positive impact on brand trust and brand attachment; further, brand trust has a significant positive impact on brand attachment and plays a partial mediating role in the impact of NE on the latter. Research limitations/implications As the nostalgic restaurant industry is the research object, the theoretical model described here may be limited to this specific industry. The potential applicability of the theoretical model to other service industries requires further study. Practical implications The results of the paper are helpful in building a good nostalgic experience, increasing consumer trust in restaurant brands, and strengthening the connection between NE and restaurant brand reconstruction. Social implications The results of the paper on the impact of NE on brand trust and brand attachment provide a referential basis and guide for services’ companies (e.g. restaurants) to revitalize the services’ brands. Originality/value The first contribution is that NE scale is constructed for the nostalgia-themed restaurants. The second contribution is that the paper reveals the mechanism of the impact of NE on brand trust and brand attachment.

scholarly journals Numerical Simulation of Borehole Parameters for Coal Seam Gas Pre-Drainage

2021 ◽  
Vol 39 (4) ◽  
pp. 1328-1334
Author(s):  
Xiaoyan Li ◽  
Jiyu Zheng ◽  
Jinpin Liu
Keyword(s):  
Numerical Simulation ◽  
Pressure Drop ◽  
Gas Pressure ◽  
Borehole Diameter ◽  
Gas Drainage ◽  
Drainage Time ◽  
Drainage Radius ◽  
Simulation Results ◽  
The Impact ◽  
The Relationship

Borehole parameters are quite important for gas drainage. This paper studies the impact of borehole diameter and time on gas drainage and performs numerical simulation on the distribution of gas pressure under the conditions of different borehole diameters and drainage times. The simulation results reveal that, as the borehole diameter increases, the gas drainage volume increases along with it and the gas pressure decreases, but such effect on gas drainage is limited. In terms of drainage time, the longer the drainage time, the greater the drainage impact scope. Taking a gas pressure drop of 51% as the indicator of the effective pre-drainage radius, the distance from the point with a gas pressure drop of 51% to the position of the borehole is the effective pre-drainage radius. When the pre-drainage reached the 30th, 45th, 60th, 75th, and 90th day, the effective pre-drainage radius was 1.04m, 1.29m, 1.51m, 1.68m, and 1.82m respectively. According to the numerical simulation results, the effective pre-drainage radius varies with the pre-drainage time, and the fitting analysis of the two indicates that the relationship between the two can be described by a power function.

scholarly journals Improving the Force and Time Response of a DC Solenoid Electromagnetic Actuator by Changing the Lower Core Angle

2021 ◽  
Vol 21 (2) ◽  
pp. 95-103
Author(s):  
Eduard Plavec ◽  
Miroslav Petrinić ◽  
Mladen Vidović
Keyword(s):  
Numerical Simulation ◽  
Time Response ◽  
Electromagnetic Actuator ◽  
Symmetric Model ◽  
The Finite Element Method ◽  
Magnetic Subsystem ◽  
Accredited Laboratory ◽  
Simulation Results ◽  
The Impact ◽  
Engineering Institute

The aim of almost any electromagnetic actuator development is to increase the electromagnetic force with which an actuator acts on a plunger with as fast a time response as possible while maintaining the dimensions as small as possible. This paper presents research on the impact of the lower core angle on the force and time response of a DC solenoid electromagnetic actuator. The research method is based on the analytical analysis of the magnetic path of the DC solenoid electromagnetic actuator and a comparison with the numerical simulation results. A transient numerical simulation was performed on a 2D axial-symmetric model of the electromagnetic actuator and included simultaneously solving time-dependent partial differential equations of the electromagnetic actuator’s magnetic, electrical, and mechanical subsystems. The magnetic subsystem was analyzed by the finite element method (FEM) using the ANSYS Electronics software package. The three prototype models with different lower core angles were produced and tested in the accredited Laboratory Center of KONČAR Electrical Engineering Institute. The obtained measurements are compared with the analytical results and numerical simulation results.

Computer Simulation of a Transportation Package Impacting Concrete and Soil Targets

2004 ◽  
Author(s):  
S. N. Huang ◽  
S. S. Shiraga ◽  
L. M. Hay
Keyword(s):  
Numerical Simulation ◽  
Computer Simulation ◽  
Impact Test ◽  
Impact Behavior ◽  
Test Results ◽  
Hypothetical Accident ◽  
Simulation Results ◽  
Accident Conditions ◽  
The Impact

This paper compares transportation mockup cask impact test results onto real surfaces with FEA numerical simulation results. The impact test results are from a series of cask impact tests that were conducted by Sandia National Laboratories (Gonzales 1987). The Sandia tests were conducted with a half-scale instrumented cask mockup impacting an essentially unyielding surface, in-situ soil, concrete runways, and concrete highways. The cask numerical simulations with these same surfaces are conducted with ABAQUS/Explicit, Version 5.8, The results are then compared and evaluated to access the viability of using numerical simulation to predict the impact behavior of transportation casks under hypothetical accident conditions.

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