Bullet Model Research Articles

Numerical study on the blocking effect of skin on Flash-Ball Impact and damage assessment

To explore the response law of non-lethal large-size kinetic energy projectiles to blunt attack on skin tissue, and to evaluate the skin injury characteristics of the attacked personnel and the use safety of kinetic energy projectiles. Based on the LS-DYNA simulation software, a three-layer skin simulation model and a Flash-Ball rubber bullet model are established, and the force-time and deformation-time biomechanical corridors of the Flash-Ball rubber bullet impacting human skin tissue are obtained. The corridor curve and the energy transfer and diffusion are analyzed and compared. The safety evaluation of the damage caused by the rubber bullet shooting a human body at different distances is carried out using the empirical formula of the penetration limit. Finally, the safe shooting distance is obtained. The results show that the model used in the simulation has a good correlation with the experimental data, its biomechanical corridor characteristics are different from those of conventional vehicle impact and small-size projectile response characteristics. The energy transfer and action time of medium and low-speed impact may cause greater damage. The fat layer is the largest energy absorption unit. The minimum safe shooting distance to ensure skin tissue from penetrating damage is 15.8 m, and the limit specific kinetic energy of skin damage is 7.88 J/cm2. This study can be extended to the study of biomechanical response law and safety evaluation under the impact of the same type of large kinetic energy projectile, which provides an important theoretical reference for the police to use large kinetic energy projectiles to conduct safe shooting in peacekeeping operations.

Modification of Wooden Ball Bullets to Improve the Skillful Motion of Bullet Repellent Games Against Elementary School Students

The modification of wooden ball bullets is a model invention with a combination of woodball sports games with bullet repulsion, this is in line with the conditions both in terms of anthropometry and physical conditions in elementary school students which is certainly less effective when using iron balls, because the learning system in elementary school students is only limited to introducing the game. The purpose of this study is that the modification of the wooden ball bullet model can be implemented for students, especially elementary schools, so that students will feel more happy and happy because the learning is very creative and relatively not monotonous and can minimize the allocation of time and the lack of existing infrastructure. In this study, the researchers used the Class Action Research method with class V student sample data consisting of 22 students. The instruments in this study used observation data collection techniques and bullet repellent skilled motion tests. From the study, it was found that there was an increase in pre-cycle to cycle I with learning completion of (54.53%) and continued in cycle II with learning completion results of (86.38%). Of course, it can be concluded that using a modified model of wooden ball bullets is very useful for the community, especially educators, in an effort to improve the movement of game skills in athletics in the bullet repulsion number.

Modelling Bathing Water Quality Using Official Monitoring Data

Predictive models of bathing water quality are a useful support to traditional monitoring and provide timely and adequate information for the protection of public health. When developing models, it is critical to select an appropriate model type and appropriate metrics to reduce errors so that the predicted outcome is reliable. It is usually necessary to conduct intensive sampling to collect a sufficient amount of data. This paper presents the process of developing a predictive model in Kaštela Bay (Adriatic Sea) using only data from regular (official) bathing water quality monitoring collected during five bathing seasons. The predictive modelling process, which included data preprocessing, model training, and model tuning, showed no silver bullet model and selected two model types that met the specified requirements: a neural network (ANN) for Escherichia coli and a random forest (RF) for intestinal enterococci. The different model types are probably the result of the different persistence of two indicator bacteria to the effects of marine environmental factors and consequently the different die-off rates. By combining these two models, the bathing water samples were classified with acceptable performances, an informedness of 71.7%, an F-score of 47.1%, and an overall accuracy of 80.6%.

Numerical Analysis of Semi-Tangential Ogive Bullet

Abstract: The objective of the present study is to design and analyze semi-tangential ogive bullets using simulatation software such as Computer-aided design & Computational Fluid Dynamics (CFD). It is observed that been a quite steady increase in the bullet research design in the past few decades. The nose section of ballistic bullet is the most important part of the design process. Hence design optimizations are achieved by adjusting the bullet's form to improve precision and stability by reducing its drag force. CFD is the study used to verify the findings. Since provides most accurate results. It is observed that present study optimizes the behavior of the at M= 2.5. This present work shows the flow of air around the bullet surface providing pressure & velocity contours at every segment. The Various parametric studies over bullet model are drag co-efficient, ballistic coefficient and turbulence viscosity are plotted’.

Experimental and numerical study on the ballistic performance of ultrahigh molecular weight polyethylene laminate

AbstractUltrahigh molecular weight polyethylene (UHMWPE) fiber orthogonally laid laminate is widely used in ballistic protection due to its excellent properties. Research on its response under bullet impact is meaningful for understanding the antiballistic mechanism and designing personal protection. In this article, three‐dimensional digital image correlation measurement and analysis method is applied to study the response of UHMWPE orthogonally laid laminates under the impact of pistol bullets. A corresponding smoothed particle hydrodynamics (SPH)–finite element method coupled numerical model is established to study the impact phenomenon. The bullet model is developed using the SPH method. The laminate is developed with multiple equivalent sublaminate finite element models. The experimental results show the damage mode and back‐face features of the laminate. First, the damage mode has two stages: the first stage includes a small number of layers that are penetrated on the impact surface and the second stage includes the expansion of the back‐face deformation. Second, the average maximum bulge height in three repeated experiments is 14.59 mm. Third, the average maximum velocity of the bulge apex position in experiments on the z‐axis is 92.32 m/s. Fourth, the maximum and minimum back‐face in‐plane shear values are 0.0893 and −0.0928, respectively. Finally, the numerical results have good agreement with the experimental results and show that the compression waves mainly propagate along the x and y directions. The experimental results can provide quantifiable features for studying the impact responses of UHMWPE laminates. The numerical model could be applied to study features that cannot be measured by experiments.

WITHDRAWN: Numeric projectile impact simulation on a server utilizing LS-DYNA

This article has been withdrawn at the request of the editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal .

Opportunities and challenges in RCS measurement of 9‐mm bullet model with 77 GHz mmwave COTS radar systems

AbstractThis article indicates a thus far unexplored area of applied research and development to the application and system engineers and researchers from broad engineering backgrounds. Results of a study are presented for measurement of calibrated Radar Cross Section (RCS) of a 9‐mm bullet (projectile) model by using a commercial‐of‐the‐shelf (COTS) millimeter wave Frequency Modulated Continuous Wave (FMCW) radar system operating in 77 to 81 GHz frequency range. The calibrated RCS variation against the aspect angle is measured experimentally, analyzed, and compared with the simulation results which shows fair matching between the two. The opportunities and challenges attached with the use of such COTS systems for development of Hostile Fire Indication (HFI) systems are discussed. This bullet type and this mmwave frequency has not been thus far studied and reported in literature. This may motivate interested individuals/entities to try to measure (at acceptable accuracy before anechoic chamber measurements) RCS of similar low‐size objects by using such low‐cost COTS platforms.

Research on active polarization imaging experiments and key technologies in smoke and dust environment

For realizing the engineering application of key technologies in the long-range active polarization imaging system, an experimental platform is built to study the static active polarization imaging technology and related image fusion algorithm in the smoke and dust environment. In the experiments, 532 nm CW laser is used as illumination source after collimation and beam expansion, metal bullet model is used as detection target, smoke environment is created through smoke generator in organic glass hood, polarization direction can be rotated by the polarizer, the images are collected by Lumerera-LM135 camera. The analysis and handling on the images are conducted by the use of the MATLAB software. In the aspects of image information entropy, average gradient, spatial frequency and standard deviation, the polarization imaging effects in various environments are quantitatively compared and analyzed, and the imaging advantages of laser illumination and polarization imaging technology in smoke and dust environment and dim conditions are verified. In order to further improve the imaging quality of active polarization imaging technology, a polarization image fusion algorithm based on fuzzy adaptive is proposed after analyzing a large number of data acquired in the experiment.The experimental results show that the active polarization imaging technology and the improved image fusion algorithm can improve the detection distance of optical system and image contrast, expand the digestible information of images for the long-range dim target imaging in low visibility environment, and provide important data reference and technology support for the application of this technology in shooting range.

Control of exterior ballistic properties of spin-stabilized bullet by optimizing internal mass distribution

Abstract This paper introduces a novel approach for controlling the exterior ballistic properties of spin-stabilized bullets by optimizing their internal mass distributions. Specifically, the properties of interest are the bullets’ stability characteristics that are examined through dynamic and gyroscopic stability parameters. New analytical expressions for aerodynamic quantities are also derived to address the compressibility of air. These expressions are utilized in a bullet model that enables efficient computation of the stability parameters for a given mass distribution. The bullet model is used in the formulation of nonlinear optimization problems that provide optimal mass distributions with respect to given goals, i.e., desired stability characteristics. The bullet types investigated in this paper are a long range bullet and a limited range training bullet. In the optimization of the mass distribution of the long range bullet, the goal is that the bullet stays stable for as long as possible. The mass distribution of the training bullet is optimized such that the bullet is stable at launch but becomes unstable shortly afterwards. The global optimal solutions obtained with the new approach fulfill the desired stability characteristics better than currently used uniformly filled bullets. Overall, the optimization approach reveals a new goal focused philosophy for bullet design compared to current trial and error design practices.

A model for evaluating the ballistic resistance of stratified packs

Models for evaluating the ballistic performance of stratified packs are useful in reducing the time for laboratory tests, understanding the failure process and identifying key factors to improve the architecture of the packs. The authors present the results of simulating the bullet impact on a packs made of 24 layers, taking into consideration the friction between layers (μ = 0.4) and the friction between bullet and layers (μ = 0.3). The aim of this study is to obtain a number of layers that allows for the bullet arrest in the packs and to have several layers undamaged in order to offer a high level of safety for this kind of packs that could be included in individual armors. The model takes into account the yield and fracture limits of the two materials the bullet is made of and those for one layer, here considered as an orthotropic material, having maximum equivalent plastic strain of 0.06. All materials are considered to have bilinear isotropic hardening behavior. After documentation, the model was designed as isothermal because thermal influence of the impact is considered low for these impact velocities. The model was developed with the help of Ansys 14.5. Each layer has 200 mm × 200 × 0.35 mm. The bullet velocity just before impact was 400 m/s, a velocity characterizing the average values obtained in close range with a ballistic barrel and the bullet model is following the shape and dimensions of the 9 mm FMJ (full metal jacket). The model and the results concerning the number of broken layers were validated by experiments, as the number of broken layers for the actual pack (made of 24 layers of LFT SB1) were also seven...eight. The models for ballistic impact are useful when they are particularly formulated for resembling to the actual system projectile - target.

THE SHAPING OF THE MULTIPOLAR PRE-PLANETARY NEBULA CRL 618 BY MULTIDIRECTIONAL BULLETS

ABSTRACT In order to understand the formation of the multipolar structures of the pre-planetary nebula CRL 618, we perform 3D simulations using a multidirectional bullet model. The optical lobes of CRL 618 and fast molecular outflows at the tips of the lobes have been found to have similar expansion ages of ∼100 yr. Additional fast molecular outflows were found near the source along the outflow axes with ages of ∼45 yr, suggesting a second episode of bullet ejections. Thus, in our simulations, two episodes of bullet ejections are assumed. The shaping process is simulated using the ZEUS-3D hydrodynamics code that includes molecular and atomic cooling. In addition, molecular chemistry is also included to calculate the CO intensity maps. Our results show the following: (1) Multiepoch bullets interacting with the toroidal dense core can produce the collimated multiple lobes as seen in CRL 618. The total mass of the bullets is ∼0.034 M ⊙, consistent with the observed high-velocity (HV) CO emission in fast molecular outflows. (2) The simulated CO J = 3–2 intensity maps show that the low-velocity cavity wall and the HV outflows along the lobes are reasonably consistent with the observations. The position–velocity diagram of the outflows along the outflow axes shows a linear increase of velocity with distance, similar to the observations. The ejections of these bullets could be due to magnetorotational explosions or nova-like explosions around a binary companion.

Selecting Serious Games for the Computer Science Class

The aim of this paper was to investigate models to select serious games for use in the computer science class. The lack of a useful framework to select serious games that meet the teaching and learning objectives presented a significant obstacle when serious games where introduced into tertiary education. This paper briefly discusses three frameworks, the RETAIN model, the four-dimensional framework, and the magic bullet model. Lecturers evaluated serious games using the guidelines suggested by each of these models and their perceptions of the models were captured using a short questionnaire. Using descriptive analysis to analyse the data, the results are that lecturers prefer the four-dimensional framework when considering and selecting serious games as a teaching tool in the computer science class. DOI: 10.5901/mjss.2014.v5n21p391

Bullet Turning at Trajectory Apex

AbstractA numerical study is carried out to investigate a 7.62-mm bullet turning at the trajectory apex, particularly when fired vertically. The bullet model includes an aerodynamic model, which basically covers angles of attack up to 180°. Computational fluid dynamics are used to estimate the aerodynamic properties at the high angles of attack. The role of aerodynamic moment, and particularly Magnus phenomena, in turning at the apex is studied. A positive Magnus moment tilts the total aerodynamic moment vector clockwise and generally drives the bullet turning nose down. The bullet turning was detected through a flat spin–type maneuver. The Magnus-moment oscillatory behavior and/or the Magnus-moment-caused bullet instability may occur during the turning at the trajectory apex. These were found to have a negligible effect on the bullet-turning launch angle, but they may contribute considerably to the bullet falling-phase behavior. Possibilities to affect the bullet descending part of the flight are also sh...

Ballistic resistance of high hardness armor steels against 7.62 mm armor piercing ammunition

Although advanced lightweight composite based armors are available, high hardness steels in military vehicles are often used to provide ballistic protection at a relatively low cost and is an interesting material due to its widespread usage in vehicle structure. In this study, ballistic limit of 500HB armor steel was determined against 7.62mm 54R B32 API hardened steel core ammunition. Lagrange and smoothed particle hydrodynamics (SPH) simulations were carried out using 3D model of bullet and high hardness armor target. Perforation tests on 9 and 20mm thickness armor were performed to validate simulation methodology. Also material tests were performed for armor steel and ammunition hardened steel core to develop Johnson–Cook constitutive relations for both strength and failure models. Finally, results from 3D numerical simulations with detailed models of bullet and target were compared with experiments. The study indicates that the ballistic limit can be quantitatively well predicted independent of chosen simulation methodology, but qualitatively some differences are seen during perforation and fragmentation. As shown in results, good agreement between Ls-Dyna simulations and experimental data was achieved by Lagrange formulation with the full bullet model.

How to Achieve Success Through Cultural Entrepreneurship

Today, most markets are seeking more than just a one-time exchange or transaction with customers. The focus of market-driven companies is on developing and sustaining relationships with their customers. Successful companies recognize that creating, communicating, and delivering value to their customers is extremely important. Marketing facilitates the exchange process and the development of relationships by carefully examining the needs and wants of consumers, developing a product or service that satisfies these needs, offering it at a certain price, making it available through a particular place or channel of distribution, and developing a program of promotion or communication to create awareness and interest. Global culture always influences how we think, feel, and behave. Because of the cultural diversity of the Indonesia, nowhere is there a greater potential for inaccurate communication and misunderstanding. Cultural pluralism depends on cultural inclusion a commitment to acknowledge, respect, and adapt to others who are differently from us. Culture and communication are inseparable. The way we communicate, what we believe, what we say, the language choices we use, and the nonverbal signals we employ are all a function of the culture we acquire. How we speak and relate nonverbally to others is learned from the culture in which we grow up. In modern society, numerous individuals, groups, and agencies constantly try to influence people’s ideas, feelings, or actions. At one time, persuasion was seen as something that one person “did to” another, following the linear magic bullet model. Now we know that influence is determined by both sources and receivers, following the simultaneous transactions model. Some cultural identities are more important than others. In a communication encounter, the greater the number of cultures the participants share, the greater the accuracy of their messages and the more satisfied they are with their exchange. We are living in an age of swiftly changing and developing communication technology in the millennium era. Mediated communication differs from face-to-face communication. Some elements of the communication process are absent or severely curtailed when people use media, including opportunities for role-taking and the availability of feedback.

On the origin of the bimodal duration distribution of gamma-ray bursts and the subjet model

The modified version of a bullet model for gamma-ray bursts (GRBs) is studied. The central engine of the source produces multiple subjets that are contained within a cone. The emission of photons in the source frame of a subjet takes place either in an infinitesimally thin shell, or during its expansion for a finite time. The analysis of the observed profiles of GRBs taken by the Burst And Transient Source Experiment leads us to the conclusion that the latter possibility is much more favoured. We also study the statistical distribution of GRBs in the context of their bimodality of durations, taking into account the capability of the detector of observing the signal above a certain flux limit. The model with shells emitting for a finite time is able to reproduce only one class of bursts, short or long, depending on the adopted physical parameters. Therefore, we suggest that the GRB bimodality is intrinsically connected with two separate classes of sources.

Three-dimensional automatic image warping in cardiac SPECT

This study presents a new tool for the visualization and analysis of three-dimensional (3-D) cardiac single-photon emission computed tomography (SPECT). The first step consisted of computing the 3-D pseudo-skeleton of a binarized myocardium and, using the skeleton points, to design a bullet model (half ellipsoid prolonged by a cylinder). Afterwards, this model was used to drive the warping of the 3-D myocardium, initially egg-shaped, into a thick, flat disc using the thin-plate splines as deformation method. Hence, instead of achieving several rotations of the initial egg-shaped volume to have an idea on the myocardial outer face (epicardial) only, the whole myocardium is seen by looking either on top of the disc-shaped transformed myocardium (epicardial surface) or underneath for the inner face (endocardial). This new shape permitted us to localize any type of defect and to evaluate its extent and depth just by a single glance. A detailed analysis, achieved after stripping away this shape in about 10 layers, allowed us to evaluate the defect extent layer by layer and to determine whether the defect involves the totality of the myocardium layers. Finally, its flattening following the ventricular long-axis led to a summed bull's eye.

The extremely high velocity CO flow in HH 7-11

New observations are made of the extremely high velocity (EHV) outflow recently discovered near HH 7-11. Maps of CO(2-1) and CO(3-2) EHV emission show that the emitting regions are compact and significantly displaced from the position of the infrared source SVS 13, which drives the outflow. The positional offset similar to the blueshifted EHV lobe and the redshifted lobe has been found for other tracers of shocked gas on the red side of the flow. The EHV lobes could be either bullets or gas swept up by jets interacting with the ambient cloud. The present evidence is not sufficient to rule out the bullet model, but the explanation that the EHV CO is swept-up material is preferable. 18 refs.

Predicted long-slit, high-resolution emission-line profiles from interstellar bow shocks. II - Arbitrary bow shock orientation

view Abstract Citations (82) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Predicted Long-Slit, High-Resolution Emission-Line Profiles from Interstellar Bow Shocks. II. Arbitrary Bow Shock Orientation Raga, A. C. ; Bohm, K. H. Abstract Theoretical position-dependent line profiles (position-velocity diagrams) of several emission lines were obtained for models of a bow shock moving at an arbitrary direction with respect to the line of sight. Models such as these have been suggested as an explanation for the emission-line spectra of Herbig-Haro objects by several authors (in connection with the interstellar bullet model, the shocked cloudlet model, or the jet model). The rather complex position-velocity diagrams of two HH objects (obtained by Boehm and Solf) can be successfully interpreted with these simple models. This is an extension of previous calculations carried out by Raga and Boehm, which were restricted to the case of a bow shock moving in the plane of the sky. Publication: The Astrophysical Journal Pub Date: September 1986 DOI: 10.1086/164554 Bibcode: 1986ApJ...308..829R Keywords: Astronomical Models; Bow Waves; Emission Spectra; Herbig-Haro Objects; Line Shape; Shock Waves; High Resolution; Interstellar Space; Pre-Main Sequence Stars; Astrophysics; LINE PROFILES; SHOCK WAVES; STARS: PRE--MAIN-SEQUENCE full text sources ADS | data products SIMBAD (5)

Predicted long-slit, high-resolution emission-like profiles from interstellar bow shocks

view Abstract Citations (101) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Predicted long-slit, high-resolution emission-like profiles from interstellar bow shocks. Raga, A. C. ; Bohm, K. -H. Abstract The position-dependent emission-line profiles (called 'position-velocity diagrams' by Choe, Bohm, and Solf) for the lines H-beta, the forbidden line of N II at 6583 A, the forbidden line of S II at 6731 A, the forbidden line of O I at 6300 A, and the forbidden line of O III at 5007 which are formed in a (somewhat simplified) model of a radiating interstellar bow shock of high Mach number have been computed. Such models have been suggested as an explanation of the emission-line spectra of Herbig-Haro objects in connection with the 'interstellar bullet model'. Some of the restrictive assumptions used in related earlier work have been eliminated. Comparing the present results to the recent high-resolution long-slit coude spectra of Herbig-Haro objects (obtained by Bohm and Solf), some important similarities are discussed. Publication: The Astrophysical Journal Supplement Series Pub Date: June 1985 DOI: 10.1086/191038 Bibcode: 1985ApJS...58..201R Keywords: Astronomical Spectroscopy; Herbig-Haro Objects; Interstellar Matter; Shock Waves; Bow Waves; High Resolution; Line Spectra; Astrophysics full text sources ADS | data products SIMBAD (1)