Projectile oblique impact on granular media: penetration depth and dynamic process

2021 ◽  
Vol 23 (2) ◽  
Author(s):  
Xiaoyan Ye ◽  
Dengming Wang ◽  
Xingyi Zhang ◽  
Chaofeng Zhang ◽  
Wei Du ◽  
...  
Keyword(s):  
Penetration Depth ◽  
Dynamic Process ◽  
Granular Media ◽  
Oblique Impact

scholarly journals Methodology for Increasing the Efficiency of Dynamic Process Calculations in Elastic Elements of Complex Engineering Constructions

Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 40
Author(s):  
Andriy Andrukhiv ◽  
Maria Sokil ◽  
Solomiia Fedushko ◽  
Yuriy Syerov ◽  
Yaryna Kalambet ◽  
...  
Keyword(s):  
Dynamic Process ◽  
Granular Media ◽  
Homogeneous Medium ◽  
Dynamic Processes ◽  
Analytical Relationship ◽  
Operational Parameters ◽  
Protective Capacity ◽  
Vibration Displacement ◽  
Complex Engineering ◽  
Elastic Elements

This study deals with a methodology for increasing the efficiency of dynamic process calculations in elastic elements of complex engineering constructions. We studied the complex dynamic processes in a simple engineering construction, a mechanical system of an elastic body–continuous flow of homogeneous medium. The developed methodology is based on the use of a priori information on some of the vibrations forms, the construction of a “simplified” mathematical model of system dynamics, and the obtaining of an analytical relationship that describe the overall range of factors on the elastic vibrations of system. The methodology is used for cases of complex vibrations of elastic bodies, and the obtained results can serve as a basis for choosing the main technological and operational parameters of elastic elements of mechanisms and machines that perform complex vibrations. The results obtained in this work are the basis for calculating the blast effect on the elements of protective structures in order to increase their protective capacity by improving the method of their attachment or by using additional reinforcement, buff load effects on the elements of drilling strings and dynamic processes that occur during surface strengthening by work hardening in order to avoid resonance phenomena, and technological processes of vibration displacement or vibration separation of granular media.

DEM Simulation on the Startup Dynamic Process of a Plain Journal Bearing Lubricated by Granular Media

2014 ◽  
Vol 57 (2) ◽  
pp. 198-205 ◽  
Author(s):  
Wei Wang ◽  
Wei Gu ◽  
Kun Liu ◽  
Fei Wang ◽  
Zhanqi Tang
Keyword(s):  
Dynamic Process ◽  
Granular Media ◽  
Journal Bearing ◽  
Dem Simulation

scholarly journals Effects of the Projectile Geometries on Normal and Oblique Penetration Using the Finite Cavity Pressure Method

2019 ◽  
Vol 9 (18) ◽  
pp. 3939 ◽  
Author(s):  
YOO ◽  
KIM ◽  
LEE
Keyword(s):  
Finite Element ◽  
Penetration Depth ◽  
Target Material ◽  
Oblique Impact ◽  
Vacuum Arc ◽  
Cavity Method ◽  
Cavity Pressure ◽  
Normal Impact ◽  
Element Analysis ◽  
Pressure Method

In this work, the penetration depth of a projectile with various geometries was analyzed using the cavity pressure method. The finite cavity method combines an analytical method and the finite element method and considers the deformation of the projectile only. This simulation method was implemented to ABAQUS/Explicit using user subroutine VDLOAD. The target material was 6061-T6511 aluminum material, and the projectile material was vacuum-arc-remelted (VAR) 4340 steel. In the analysis, the normal impact and the oblique impact with the angle of 30° were studied. First, the developed simulation model was verified using the previous experiments. With the developed finite element analysis with the cavity pressure method, the effect of projectile shape on penetration was investigated. The target geometry maximizes penetration depth was discussed. The angle of the nose affects mainly on the penetration characteristics. The projectile having an ogive nose with high caliber-radius-head (CRH) value shows the best penetration depth and the least plastic deformation in both the normal impact and the oblique impact.

Penetration of Rigid Projectile into Concrete Target with Effect of Attack Angle: Theory and Experiment

2017 ◽  
Vol 17 (08) ◽  
pp. 1750080 ◽  
Author(s):  
Wanxiang Chen ◽  
Yanyan Zhang ◽  
Zhikun Guo ◽  
Huihui Zou
Keyword(s):  
Penetration Depth ◽  
Initial Conditions ◽  
Equations Of Motion ◽  
Oblique Impact ◽  
Attack Angle ◽  
Influence Coefficient ◽  
Depth Of Penetration ◽  
Rigid Projectile ◽  
Simplified Formula ◽  
Concrete Target

The existing prediction methods of penetration depth do not take the influence of attack angle or angular velocity of projectile (i.e. effect of attack angle) into account. The main purpose of this work is to develop an approximate approach to predict the penetration depth for a rigid projectile into concrete target covered with yaw-inducing overlays. A quasi-static, elastic–plastic contact model of projectile impacting on irregular barrier is built based on Hertz’s contact theory, and the expression of effect of attack angle are also presented. The stress on projectile–target interface is derived according to spherical cavity expansion model and mechanical property of target, where reduction coefficient is introduced to consider the effect of free surface, and the penetration resistances are further obtained. Differential equations of motion for projectile arbitrarily oblique into target covered with yaw-inducing overlays are given by employing the initial conditions of projectile striking on irregular barrier. Then a simplified formula of depth-of-penetration (DOP) with effect of attack angle is presented by introducing an influence coefficient of oblique impact and an influence coefficient of yaw-inducing overlays into the depth of normal penetration. Predictions from the simplified formula are validated by comparison with ballistic experimental data for a 57[Formula: see text]mm diameter, 4.44[Formula: see text]kg, and ogive-nose, semi-armor-piercing with striking velocities between 320 and 705[Formula: see text]m/s.

Investigation of Solidification Characteristics of Resin for Integral Stereolithography System

2011 ◽  
Vol 142 ◽  
pp. 50-53
Author(s):  
Guang Shen Xu ◽  
Gen Yang ◽  
Jing Gong ◽  
Jian Yang
Keyword(s):  
Penetration Depth ◽  
Dynamic Characteristics ◽  
Dynamic Process ◽  
Least Square Method ◽  
Least Square ◽  
Liquid Resin ◽  
Resin Penetration

Photo-curable resin’s solidification under beam exposure in integral stereolithography (SL) is a dynamic process. Firstly, the up-part in photo-curable resin solidifies after absorbing enough energy; and then with the beam exposure, after the beam penetrates the solidified resin, the liquid resin under solidified resin have the opportunity to be cured. But the model which describes the solidification characteristics for photo-curable resin in SL process does not reflect the dynamic characteristics, and obvious predicting error will be introduced. In this paper, a solidification characteristics model of the photo-curable resin UV-2230, which describes the resin’s dynamic characteristics in solidifying process, is established with least square method in experiments. By using the model, critical exposure of the resin, penetration depth of the liquid resin and penetration depth of the solid resin are obtained. The research provides a base for improving the building accuracy for integral SL system.

Penetration of spheres into loose granular media

2004 ◽  
Vol 82 (6) ◽  
pp. 439-446 ◽  
Author(s):  
J R de Bruyn ◽  
A M Walsh
Keyword(s):  
Yield Stress ◽  
Penetration Depth ◽  
Newtonian Fluid ◽  
Granular Medium ◽  
Effective Viscosity ◽  
Granular Media ◽  
Experimental Results ◽  
Incident Momentum ◽  
Small Glass ◽  
Zero Momentum

We study the penetration of steel spheres dropped vertically into a container of loosely packed, small glass beads. We find that the penetration depth of the spheres increases linearly with the incident momentum of the projectile, but with a zero-momentum intercept that can be either positive or negative. This behavior can be understood by modelling the granular medium as a non-Newtonian fluid with a yield stress and an effective viscosity. We derive the scaling behavior of the viscosity and find agreement with our experimental results. PACS Nos.: 45.70.–n, 83.80.Fg, 47.50.+d

Red Flags: Barriers to Listening and Spoken Language in Children with Hearing Loss

2014 ◽  
Vol 24 (1) ◽  
pp. 11-18
Author(s):  
Andrea Bell ◽  
K. Todd Houston
Keyword(s):  
Hearing Loss ◽  
Early Diagnosis ◽  
Skill Acquisition ◽  
Dynamic Process ◽  
Spoken Language ◽  
Red Flags ◽  
Careful Monitoring ◽  
Auditory Development ◽  
Children With Hearing Loss ◽  
Family Centered

To ensure optimal auditory development for the acquisition of spoken language, children with hearing loss require early diagnosis, effective ongoing audiological management, well fit and maintained hearing technology, and appropriate family-centered early intervention. When these elements are in place, children with hearing loss can achieve developmental and communicative outcomes that are comparable to their hearing peers. However, for these outcomes to occur, clinicians—early interventionists, speech-language pathologists, and pediatric audiologists—must participate in a dynamic process that requires careful monitoring of countless variables that could impact the child's skill acquisition. This paper addresses some of these variables or “red flags,” which often are indicators of both minor and major issues that clinicians may encounter when delivering services to young children with hearing loss and their families.

COVID-19 complicated by pulmonary embolism treated with catheter directed thrombectomy

VASA ◽  
2020 ◽  
Vol 49 (4) ◽  
pp. 333-337 ◽  
Author(s):  
Francisco Leonardo Galastri ◽  
Leonardo Guedes Moreira Valle ◽  
Breno Boueri Affonso ◽  
Marcela Juliano Silva ◽  
Rodrigo Gobbo Garcia ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
High Risk ◽  
Dynamic Process ◽  
Therapeutic Option ◽  
Massive Pulmonary Embolism ◽  
Percutaneous Intervention ◽  
Thromboembolic Events ◽  
Emergency Center ◽  
Catheter Directed Thrombolysis

Summary: COVID-19 is a recently identified illness that is associated with thromboembolic events. We report a case of pulmonary embolism in a patient with COVID-19, treated by catheter directed thrombectomy. A 57 year old patient presented to the emergency center with severe COVID-19 symptoms and developed massive pulmonary embolism. The patient was treated with catheter directed thrombolysis (CDT) and recovered completely. Coagulopathy associated with COVID-19 is present in all severe cases and is a dynamic process. We describe a case of massive/high risk pulmonary embolism, in a patient with COVID-19 receiving full anticoagulation, who was treated by percutaneous intervention. CDT can be an additional therapeutic option in patients with COVID-19 and pulmonary embolism that present with rapid clinical collapse.

Sign in / Sign up

Export Citation Format

Share Document