The Impact of the Conical Indenter on a Plate Laying on a Winkler Foundation

2018 ◽  
Vol 931 ◽  
pp. 84-90 ◽  
Author(s):  
Aleksey N. Beskopylny ◽  
Andrey A. Veremeenko ◽  
Elena E. Kadomtseva ◽  
Natalia I. Beskopylnaia
Keyword(s):  
Contact Time ◽  
Mechanical Characteristics ◽  
Strength Characteristics ◽  
Winkler Foundation ◽  
Building Structures ◽  
Dynamic Impact ◽  
Conical Indenter ◽  
Elastic Plastic ◽  
Plastic Indentation ◽  
The Impact

In the practice of civil engineering, the methods of impact diagnostics of materials find their application, allowing quickly and accurately measure the required strength characteristics at any point in the structure. Impact methods offer many advantages, for example, at smaller dimensions can be developed big the contact force, it can be recorded more information about the response of the material to dynamic impact and others. This approach is widely used in determining the hardness of materials and makes it possible to determine the complex mechanical characteristics: yield strength, ultimate strength, and elongation. In the paper we consider the axisymmetric problem of the impact of the conical indenter on the plate, laying on Winkler Foundation under elastic-plastic deformation. The solution is based on the phenomenological model of elastic-plastic indentation in a quasistatic formulation. The general deformations of the plate are considered elastic, and the local, in the contact zone, are elastoplastic. The main characteristics of the impact are determined: the force of the contact interaction, the local indentation, the contact time. The device and methods of determining the strength characteristics of plates under specified conditions of impact were developed on the basis of obtained solutions. The proposed method has been tested on many building structures: bridges, trusses, structural structures of artificial structures, reinforcement bars, welded joints.

scholarly journals A lattice Boltzmann simulation of oblique impact of a single rain droplet on super-hydrophobic surface with randomly distributed rough structures

2020 ◽  
Vol 15 (3) ◽  
pp. 443-449
Author(s):  
Zhang Shusheng ◽  
Lu Hao ◽  
Zhang Li-Zhi ◽  
Riffat Saffa ◽  
Ure Zafer ◽  
...  
Keyword(s):  
Lattice Boltzmann ◽  
Contact Time ◽  
Hydrophobic Surface ◽  
Impact Angle ◽  
Oblique Impact ◽  
Building Structures ◽  
Pinning Effect ◽  
Lattice Boltzmann Simulation ◽  
Boltzmann Method ◽  
The Impact

Abstract In this paper, oblique impact of a single rain droplet on super-hydrophobic surface with randomly distributed rough structures was investigated by lattice Boltzmann method. The effects of the impact angle of the droplet as well as the skewness and kurtosis of rough surface on the bouncing ability of the droplet were in this paper. It was found that the oblique impact can effectively reduce the contact time in the process of droplet bouncing off, because the energy consumption caused by the pinning effect is reduced. Moreover, the contact time most possibly reaches the shortest when the impact angle is 45°. Decreasing the skewness and keeping the kurtosis around 4.0 can enhance the bouncing ability during the droplet oblique impact on randomly distributed rough surfaces. The results are useful for the design of building structures.

The Impact of an Elastic Sphere on a Thin Elastic Plate Supported by a Winkler Foundation

1975 ◽  
Vol 42 (1) ◽  
pp. 133-135 ◽  
Author(s):  
H. D. Fisher
Keyword(s):  
Thin Plate ◽  
Contact Time ◽  
Viscoelastic Plate ◽  
Coefficient Of Restitution ◽  
Solution Technique ◽  
Rigid Sphere ◽  
Winkler Foundation ◽  
Thin Elastic Plate ◽  
Continuous Contact ◽  
The Impact

This paper investigates the elastic impact of a sphere on a thin plate which is in continuous contact with a foundation. The reaction pressure is considered to be proportional to the local deflection (Winkler hypothesis). A solution technique, which was originally developed to analyze the impact of a rigid sphere on a viscoelastic plate, is modified for application in the present study. The contact force, the coefficient of restitution, and the contact time are computed for a wide variation in the two dimensionless parameters which are required to describe a given problem. For the limiting cases of impact on a half space and impact on a thin plate supported by a rigid foundation, the contact time computed here is shown to correlate with the calculations of earlier investigators.

scholarly journals The non-stationary dynamic of a beam under the elastic-plastic impact of a conical indenter

2019 ◽  
Vol 279 ◽  
pp. 02006
Author(s):  
Alexey Beskopylny ◽  
Andrey Veremeenko ◽  
Elena Kadomtseva ◽  
Natalia Beskopylnaia
Keyword(s):  
Wave Equations ◽  
Numerical Study ◽  
Ansys Software ◽  
Conical Indenter ◽  
Elastic Plastic ◽  
Impact Interaction ◽  
Indentation Process ◽  
The Impact ◽  
Non Destructive ◽  
Construction Practice

The problem of impact interaction of a conical indenter with the surface of a steel beam under elastic-plastic deformation is considered. The analysis of the dynamic reaction of the beam to the impact is considered analytically and numerically. The analytical solution is based on the phenomenological model of conical indentation and the solution of wave equations of beam dynamics at impact. The numerical study of the indentation process was carried out using the ANSYS software. The dynamic response of the beam is analyzed for different geometric parameters and different values of strength characteristics. Such tasks are widely used in construction practice in the implementation of non-destructive methods of assessing the mechanical characteristics of structures.

scholarly journals Dynamic response of a plate laying on elastic base during the impact of a conical indenter

2018 ◽  
Vol 196 ◽  
pp. 01001 ◽  
Author(s):  
Alexey Beskopylny ◽  
Andrey Veremeenko ◽  
Elena Kadomtseva ◽  
Alexander Shilov
Keyword(s):  
Dynamic Response ◽  
Fourier Transforms ◽  
Numerical Study ◽  
Elastic Base ◽  
Elastic Displacement ◽  
Special Device ◽  
Conical Indenter ◽  
Impact Process ◽  
Elastic Plastic ◽  
The Impact

The article presents an analytical and numerical study of a dynamic conical indentation during impact process. The circular plate laying on the elastic base is subjected to impact load by the conical indenter. Local deformations in imprint zone are considered as elastic-plastic and general plate deformations are only elastic. According to Timoshenko method, the general plate displacement is considered as the sum of the elastic-plastic displacement of the indenter and the elastic displacement of the plate at the impact point. The solution is constructed with Fourier transforms and the Green function of the dynamic process is obtained. The numerical study of impact indentation is received by FEM method. The dependences of displacements, velocities, and accelerations of the plate on time is obtained during impact. The experimental data obtained with the special device is compared with the results of the numerical analysis. The method of an assessment of the mechanical characteristics of steel is proposed on the basis of the research. Analysis of the dynamic response and non-stationary effects on structural elements is carried out on the base of the calculated impact process.

Impact of Particulate Matter on Distribution System Disinfection Efficacy

2008 ◽  
Vol 43 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Linda Wojcicka ◽  
Carole Baxter ◽  
Ron Hofmann
Keyword(s):  
Helicobacter Pylori ◽  
Particulate Matter ◽  
Distribution System ◽  
Contact Time ◽  
Water Disinfection ◽  
Sphingomonas Paucimobilis ◽  
Soil Corrosion ◽  
Log Reduction ◽  
Drinking Water Disinfection ◽  
The Impact

Abstract Microorganisms have been shown to survive drinking water disinfection and remain viable in disinfected waters despite the presence of disinfectant residuals. This may be partially attributed to protection by particulate matter. The aim of this study was to determine the effects of the presence of particulate matter on disinfection kinetics. Sphingomonas paucimobilis ATCC 10829 and Helicobacter pylori ATCC 43504 were used in inactivation experiments in the presence and absence of soil, corrosion, and wastewater particles. The results showed that the presence of such particles tended to inhibit chlorine and monochloramine inactivation, although the magnitude of the impact under the conditions tested was small (e.g., 1-log reduction in inactivation for several minutes of contact time in the presence of less than 1 mg/L of disinfectant).

Ferro-nanofluid squeeze film lubrication with heat transfer

2021 ◽  
pp. 135065012110276
Author(s):  
Manimegalai Kavarthalai ◽  
Vimala Ponnuswamy
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Contact Time ◽  
Transfer Rate ◽  
Fluid Layer ◽  
Darcy Law ◽  
Squeeze Film ◽  
Mean Temperature ◽  
Special Cases ◽  
The Impact

A theoretical study of a squeezing ferro-nanofluid flow including thermal effects is carried out with application to bearings and articular cartilages. A representational geometry of the thin layer of a ferro-nanofluid squeezed between a flat rigid disk and a thin porous bed is considered. The flow behaviours and heat transfer in the fluid and porous regions are investigated. The mathematical problem is formulated based on the Neuringer–Rosensweig model for ferro-nanofluids in the fluid region including an external magnetic field, Darcy law for the porous region and Beavers–Joseph slip condition at the fluid–porous interface. The expressions for velocity, fluid film thickness, contact time, fluid flux, streamlines, pathlines, mean temperature and heat transfer rate in the fluid and porous regions are obtained by using a perturbation method. An asymptotic solution for the fluid layer thickness is also presented. The problem is also solved by a numerical method and the results by asymptotic analysis, perturbation and numerical methods are obtained assuming a constant force squeezing state and are compared. It is shown that the results obtained by all the methods agree well with each other. The effects of various parameters such as Darcy number, Beavers–Joseph constant and magnetization parameter on the flow behaviours, contact time, mean temperature and heat transfer rate are investigated. The novel results showing the impact of using ferro-nanofluids in the two applications under consideration are presented. The results under special cases are further compared with the existing results in the literature and are found to agree well.

Rupture by impact-induced fatigue of a copper foil strip embedded in a multifunctional composite material

2021 ◽  
pp. 002199832199432
Author(s):  
Yacine Ouroua ◽  
Said Abdi ◽  
Imene Bachirbey
Keyword(s):  
Composite Material ◽  
Mechanical Characteristics ◽  
Glass Fibers ◽  
Energy Levels ◽  
Fatigue Tests ◽  
Repeated Impact ◽  
Aeronautical Industry ◽  
Repeated Impacts ◽  
Cracking Mode ◽  
The Impact

Multifunctional composite materials are highly sought-after by the aerospace and aeronautical industry but their performance depends on their ability to sustain various forms of damages, in particular damages due to repeated impacts. In this work we studied the mechanical behavior of a layered glass-epoxy composite with copper inserts subjected to fatigue under repeated impacts with different energy levels. Damage evolution as a function of impact energy was carefully monitored in order to determine the effect of the copper inserts on mechanical characteristics of the multifunctional composite, such as endurance and life. Results of repeated impact tests show that electric current interruption in the copper inserts occurs prior to the total perforation of the composite material, and after about 75% of the total number of impacts to failure. This is the case for the three energy levels considered in this study, [Formula: see text] = 2, 3 and 4 Joules. The epoxy resin was dissolved chemically in order to preserve the mechanical structure of the damaged copper inserts and the composite fibers for further inspection and analysis. Scanning electron microscopy (SEM) of the fractured copper inserts revealed interesting information on the nature of the damage, including information on plastic deformation, strain hardening, cracking mode, temperature increase during the impacts, and most importantly the glass fibers and their roles during the impact-fatigue tests.

Study on Grinding Force in Two-Dimensional Ultrasonic Grinding Nano-Ceramics

2010 ◽  
Vol 42 ◽  
pp. 204-208 ◽  
Author(s):  
Xiang Dong Li ◽  
Quan Cai Wang
Keyword(s):  
Mathematical Model ◽  
Ultrasonic Vibration ◽  
Contact Time ◽  
Reaction Force ◽  
Grinding Force ◽  
Two Dimensional ◽  
Indentation Fracture ◽  
Ultrasonic Grinding ◽  
The Impact ◽  
Ultrasonic Vibration Assisted Grinding

In this paper, the characteristic of grinding force in two-dimensional ultrasonic vibration assisted grinding nano-ceramic was studied by experiment based on indentation fracture mechanics, and mathematical model of grinding force was established. The study shows that grinding force mainly result from the impact of the grains on the workpiece in ultrasonic grinding, and the pulse power is much larger than normal grinding force. The ultrasonic vibration frequency is so high and the contact time of grains with the workpiece is so short that the pulse force will be balanced by reaction force from workpiece. In grinding workpiece was loaded by the periodical stress field, which accelerates the fatigue fracture.

scholarly journals Drops bouncing off macro-textured superhydrophobic surfaces

2017 ◽  
Vol 824 ◽  
pp. 866-885 ◽  
Author(s):  
Ali Mazloomi Moqaddam ◽  
Shyam S. Chikatamarla ◽  
Iliya V. Karlin
Keyword(s):  
Contact Time ◽  
Numerical Study ◽  
Three Dimensional ◽  
Superhydrophobic Surfaces ◽  
Nonlinear Behaviour ◽  
Textured Surfaces ◽  
Texture Density ◽  
Wide Range ◽  
Quantitative Manner ◽  
The Impact

Recent experiments with droplets impacting macro-textured superhydrophobic surfaces revealed new regimes of bouncing with a remarkable reduction of the contact time. Here we present a comprehensive numerical study that reveals the physics behind these new bouncing regimes and quantifies the roles played by various external and internal forces. For the first time, accurate three-dimensional simulations involving realistic macro-textured surfaces are performed. After demonstrating that simulations reproduce experiments in a quantitative manner, the study is focused on analysing the flow situations beyond current experiments. We show that the experimentally observed reduction of contact time extends to higher Weber numbers, and analyse the role played by the texture density. Moreover, we report a nonlinear behaviour of the contact time with the increase of the Weber number for imperfectly coated textures, and study the impact on tilted surfaces in a wide range of Weber numbers. Finally, we present novel energy analysis techniques that elaborate and quantify the interplay between the kinetic and surface energy, and the role played by the dissipation for various Weber numbers.

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