A Study on the Ricochet of Concrete Debris Against Soil

2015 ◽  
Vol 12 (04) ◽  
pp. 1540009 ◽  
Author(s):  
J. Xu ◽  
C. K. Lee ◽  
S. C. Fan
Keyword(s):  
Numerical Modeling ◽  
Kinetic Energy ◽  
Incident Angle ◽  
Experimental Results ◽  
Impact Process ◽  
Impact Responses ◽  
The Impact

In this study, the impact responses of concrete debris against soil are investigated. Three types of concrete debris are shot at soil with different incident conditions in experiments. A numerical modeling for the impact process is established and calibrated by the experimental results. A further study on the effect of debris size is then carried out based on the calibrated numerical modeling. A set of formulation is presented to predict the outgoing velocity and the outgoing angle in terms of the incident velocity and the incident angle. Critical lethality curves are derived based on the assumption of a critical kinetic energy of 79 J.

Experimental study of spreading characteristics of droplet impacting on canopy fabric surface

2017 ◽  
Vol 31 (34) ◽  
pp. 1750325 ◽  
Author(s):  
Han Cheng ◽  
Chao Qiu ◽  
Changchun Zhou ◽  
Xuebin Sun ◽  
Rui Yang
Keyword(s):  
Experimental Study ◽  
Kinetic Energy ◽  
Impact Velocity ◽  
Working Conditions ◽  
Experimental Results ◽  
Initial Kinetic Energy ◽  
Droplet Spreading ◽  
Visualization Technology ◽  
Fabric Surface ◽  
The Impact

A new experiment based on visualization technology is designed to study the spreading characteristics of droplet impacting on canopy fabric. The processes of droplet impacting on 66 type polyamide grid silk are captured. The experimental results show that the spreading characteristics are also affected by fabric pretension and fabric permeability. The pretension is favorable for the droplet to reach the final equilibrium stage. The impact velocity determines the initial kinetic energy and plays a major role in the droplet spreading. The fabric permeability determines the wettability and has different effects on spreading characteristics under different working conditions. In addition, the above factors can enhance the two competitive processes of spreading and imbibing at the same time. The spreading characteristics depend on which process is the dominant one.

Study of the Impact Toughness Experiment of SiCp/Al FGM and Numerical Simulation

2012 ◽  
Vol 268-270 ◽  
pp. 134-137
Author(s):  
Jin Li ◽  
Liang Yi Li ◽  
Zheng Yuan
Keyword(s):  
Numerical Simulation ◽  
Silicon Carbide ◽  
Impact Toughness ◽  
Cold Isostatic Pressing ◽  
Experimental Results ◽  
Gradient Materials ◽  
Impact Process ◽  
Simulation Results ◽  
Microstructure Density ◽  
The Impact

This paper by cold isostatic pressing and sintering of combining the method of preparation of silicon carbide enhance aluminum functional gradient materials, and the microstructure, density, impact toughness are analyzed, the results of experiments showed that in the aluminum gradient to join in the silicon carbide enhance particles, The impact toughness of the material has been obviously improved. Using ANSYS Numerical simulation Impact process, the simulation results anastomosis with the experimental results.

Spatial Impact of a Slender Beam

2003 ◽  
Vol 125 (4) ◽  
pp. 368-371 ◽  
Author(s):  
Horatiu Barbulescu ◽  
Dan B. Marghitu ◽  
Uday Vaidya
Keyword(s):  
Kinetic Energy ◽  
Incident Angle ◽  
Contact Point ◽  
Equations Of Motion ◽  
Tangential Component ◽  
Sliding Direction ◽  
Generalized Momentum ◽  
Separation Force ◽  
The Impact

In this paper, the dynamics of the spatial impact of a slender beam is analyzed. The equations of motion are calculated using Kane’s impact method. The generalized momentum and generalized impulse of the beam are considered to find the equations of motion of the beam. The frictional phenomenon at the contact point is analyzed. For the case of impact without slipping, it is used the assumption that the tangential component of the velocity of separation is null. In the case with slipping, the tangential impulse (at the plane of impact) is computed. The sliding direction after impact is calculated. A simulation of the impact of beam with a surface is developed and the velocity of separation, force of impact and kinetic energy of the beam after impact are studied for different incident angles of the beam. The incident angle is varied from 0 deg to 57 deg. The results are function of the incident angle of impact.

Energy, Torque, and Dynamics in Impact Wrench Tightening

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Paul Wallace
Keyword(s):  
Kinetic Energy ◽  
Elastic Deformation ◽  
Energy Model ◽  
Bolted Joints ◽  
Output Shaft ◽  
Bolted Joint ◽  
Dynamic Measurements ◽  
Impact Process ◽  
Joint Characteristics ◽  
The Impact

Dynamic measurements were made on an impact wrench tightening several bolted joints. Using hammer energy and bolted joint characteristics, energy absorbed by the joint and other parts of the system was calculated. The impact process is found to be consistent with an energy model in which kinetic energy of the tool hammer is primarily absorbed by the bolted joint. Hammer energy was also absorbed by elastic deformation of the tool output shaft and by friction-type losses in the components being assembled. Bolt torque is closely correlated with hammer energy delivered by the tool as was hammer rebound angle.

Multislice calculations of RHEED patterns from vicinal Si (001)

1993 ◽  
Vol 51 ◽  
pp. 1000-1001
Author(s):  
Scott Lordi
Keyword(s):  
Misorientation Angle ◽  
Incident Angle ◽  
Incident Beam ◽  
Experimental Results ◽  
Bragg Condition ◽  
Vicinal Surfaces ◽  
Kinematic Theory ◽  
Step Edges

Vicinal Si (001) surfaces are interesting because they are good substrates for the growth of III-V semiconductors. Spots in RHEED patterns from vicinal surfaces are split due to scattering from ordered step arrays and this splitting can be used to determine the misorientation angle, using kinematic arguments. Kinematic theory is generally regarded to be inadequate for the calculation of RHEED intensities; however, only a few dynamical RHEED simulations have been attempted for vicinal surfaces. The multislice formulation of Cowley and Moodie with a recently developed edge patching method was used to calculate RHEED patterns from vicinal Si (001) surfaces. The calculated patterns are qualitatively similar to published experimental results and the positions of the split spots quantitatively agree with kinematic calculations.RHEED patterns were calculated for unreconstructed (bulk terminated) Si (001) surfaces misoriented towards [110] ,with an energy of 15 keV, at an incident angle of 36.63 mrad ([004] bragg condition), and a beam azimuth of [110] (perpendicular to the step edges) and the incident beam pointed down the step staircase.

The Impact of Cash Mobs in the Vote with the Wallet Game: Experimental Results

2016 ◽  
Author(s):  
Leonardo Becchetti ◽  
Maurizio Fiaschetti ◽  
Francesco Salustri
Keyword(s):  
Experimental Results ◽  
The Impact

scholarly journals Experimental study of the supercritical CO 2 diffusion coefficient in porous media under reservoir conditions

2019 ◽  
Vol 6 (6) ◽  
pp. 181902 ◽  
Author(s):  
Junchen Lv ◽  
Yuan Chi ◽  
Changzhong Zhao ◽  
Yi Zhang ◽  
Hailin Mu
Keyword(s):  
Porous Media ◽  
Diffusion Coefficient ◽  
Oil Recovery ◽  
Carbon Capture ◽  
Carbon Capture And Storage ◽  
Elevated Pressure ◽  
Experimental Results ◽  
Saturated Porous Media ◽  
Reservoir Conditions ◽  
The Impact

Reliable measurement of the CO 2 diffusion coefficient in consolidated oil-saturated porous media is critical for the design and performance of CO 2 -enhanced oil recovery (EOR) and carbon capture and storage (CCS) projects. A thorough experimental investigation of the supercritical CO 2 diffusion in n -decane-saturated Berea cores with permeabilities of 50 and 100 mD was conducted in this study at elevated pressure (10–25 MPa) and temperature (333.15–373.15 K), which simulated actual reservoir conditions. The supercritical CO 2 diffusion coefficients in the Berea cores were calculated by a model appropriate for diffusion in porous media based on Fick's Law. The results show that the supercritical CO 2 diffusion coefficient increases as the pressure, temperature and permeability increase. The supercritical CO 2 diffusion coefficient first increases slowly at 10 MPa and then grows significantly with increasing pressure. The impact of the pressure decreases at elevated temperature. The effect of permeability remains steady despite the temperature change during the experiments. The effect of gas state and porous media on the supercritical CO 2 diffusion coefficient was further discussed by comparing the results of this study with previous study. Based on the experimental results, an empirical correlation for supercritical CO 2 diffusion coefficient in n -decane-saturated porous media was developed. The experimental results contribute to the study of supercritical CO 2 diffusion in compact porous media.

scholarly journals A New Method to Determine the Impact of Individual Field Quantities on Cycle-to-Cycle Variations in a Spark-Ignited Gas Engine

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4136
Author(s):  
Clemens Gößnitzer ◽  
Shawn Givler
Keyword(s):  
Kinetic Energy ◽  
Flow Field ◽  
Turbulent Kinetic Energy ◽  
Negative Impact ◽  
Operating Conditions ◽  
Engine Operation ◽  
Gas Engine ◽  
Cycle Simulation ◽  
Simulation Results ◽  
The Impact

Cycle-to-cycle variations (CCV) in spark-ignited (SI) engines impose performance limitations and in the extreme limit can lead to very strong, potentially damaging cycles. Thus, CCV force sub-optimal engine operating conditions. A deeper understanding of CCV is key to enabling control strategies, improving engine design and reducing the negative impact of CCV on engine operation. This paper presents a new simulation strategy which allows investigation of the impact of individual physical quantities (e.g., flow field or turbulence quantities) on CCV separately. As a first step, multi-cycle unsteady Reynolds-averaged Navier–Stokes (uRANS) computational fluid dynamics (CFD) simulations of a spark-ignited natural gas engine are performed. For each cycle, simulation results just prior to each spark timing are taken. Next, simulation results from different cycles are combined: one quantity, e.g., the flow field, is extracted from a snapshot of one given cycle, and all other quantities are taken from a snapshot from a different cycle. Such a combination yields a new snapshot. With the combined snapshot, the simulation is continued until the end of combustion. The results obtained with combined snapshots show that the velocity field seems to have the highest impact on CCV. Turbulence intensity, quantified by the turbulent kinetic energy and turbulent kinetic energy dissipation rate, has a similar value for all snapshots. Thus, their impact on CCV is small compared to the flow field. This novel methodology is very flexible and allows investigation of the sources of CCV which have been difficult to investigate in the past.

A Study on Evolution of Splat Radius and Temperature in Thermal Spray Process

2018 ◽  
Author(s):  
Manpreet Dash ◽  
Sangharsh Kumar ◽  
Partha Pratim Bandyopadhyay ◽  
Anandaroop Bhattacharya
Keyword(s):  
Heat Transfer ◽  
Thermal Spray ◽  
Molten Metal ◽  
Spray Deposition ◽  
Substrate Surface ◽  
Metal Droplet ◽  
Droplet Impingement ◽  
Impact Process ◽  
The Impact ◽  
Maximum Spreading

The impact process of a molten metal droplet impinging on a solid substrate surface is encountered in several technological applications such as ink-jet printing, spray cooling, coating processes, spray deposition of metal alloys, thermal spray coatings, manufacturing processes and fabrication and in industrial applications concerning thermal spray processes. Deposition of a molten material or metal in form of a droplet on a substrate surface by propelling it towards it forms the core of the spraying process. During the impact process, the molten metal droplet spreads radially and simultaneously starts losing heat due to heat transfer to the substrate surface. The associated heat transfer influences impingement behavior. The physics of droplet impingement is not only related to the fluid dynamics, but also to the respective interfacial properties of solid and liquid. For most applications, maximum spreading diameter of the splat is considered to be an important factor for droplet impingement on solid surfaces. In the present study, we have developed a model for droplet impingement based on energy conservation principle to predict the maximum spreading radius and the radius as a function of time. Further, we have used the radius as a function of time in the heat transfer equations and to study the evolution of splat-temperature and predict the spreading factor and the spreading time and mathematically correlate them to the spraying parameters and material properties.

scholarly journals Three doors anomaly, “should I stay, or should I go”: an artefactual field experiment

2021 ◽  
Author(s):  
Andrea Morone ◽  
Rocco Caferra ◽  
Alessia Casamassima ◽  
Alessandro Cascavilla ◽  
Paola Tiranzoni
Keyword(s):  
Field Experiment ◽  
Experimental Evidence ◽  
Bayesian Updating ◽  
Anomalous Behavior ◽  
Status Quo ◽  
Experimental Results ◽  
Illusion Of Control ◽  
Optimal Decision ◽  
Status Quo Bias ◽  
The Impact

AbstractThis work aims to identify and quantify the biases behind the anomalous behavior of people when they deal with the Three Doors dilemma, which is a really simple but counterintuitive game. Carrying out an artefactual field experiment and proposing eight different treatments to isolate the anomalies, we provide new interesting experimental evidence on the reasons why subjects fail to take the optimal decision. According to the experimental results, we are able to quantify the size and the impact of three main biases that explain the anomalous behavior of participants: Bayesian updating, illusion of control and status quo bias.

Sign in / Sign up

Export Citation Format

Share Document