scholarly journals Impact Behavior of a Rotating Rigid Body with Impact and Viscous Friction

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Dorian Cojocaru ◽  
Dan B. Marghitu
Keyword(s):  
Viscous Friction ◽  
Friction Model ◽  
Contact Forces ◽  
Hertzian Contact ◽  
Impact Behavior ◽  
Element Analysis ◽  
Friction Parameters ◽  
Friction Function ◽  
Coulomb Dry Friction ◽  
The Impact

The impact between a rotating link and a solid flat surface is considered. For the impact, we consider three distinct periods: elastic period, elastoplastic period, and restitution period. A Hertzian contact force is considered for the elastic period. Nonlinear contact forces developed from finite element analysis are used for the remaining two phases. The tangential effect is taken into account considering a friction force that combines the Coulomb dry friction model and a viscous friction function of velocity. Simulations results are obtained for different friction parameters. An experimental setup was designed to measure the contact time during impact. The experimental and simulation results are compared for different lengths of the link.

Vibrations due to Impact in a Non Ideal Mechanical System With a Non-Linear Hertzian Contact Model

2014 ◽  
Author(s):  
Helio A. Navarro ◽  
Jose M. Balthazar ◽  
Reyolando M. L. R. F. Brasil
Keyword(s):  
Mechanical System ◽  
Rigid Wall ◽  
Contact Forces ◽  
Hertzian Contact ◽  
Impact Behavior ◽  
Steady State Responses ◽  
Post Impact ◽  
The Impact ◽  
The Mathematical Model ◽  
State Responses

This work analyses the post impact behavior of a mechanical system consisting of an oscillator and an unbalanced non–ideal electrical motor. The impact between the mechanical system and a rigid wall is based on the assumption that the impacting bodies undergo local deformations. The method used in the present work is similar to the Discrete Element Method for particle systems modeled with a “soft–sphere” mechanism. The contact forces are modeled using a nonlinear damped Hertzian Spring-Dashpot system. The mathematical model of the mechanical system is represented by a set of nonlinear ordinary differential equations. The transient and steady-state responses are discussed. As the motor is considered a non ideal energy source, the Sommerfeld effect is also analyzed. The impact model is first applied for a single freely falling particle and then in the proposed mechanical system. Non-dimensional expressions for the contact force and numerical simulations of the mechanical system behavior are also presented.

scholarly journals Effect of In-Situ Synthesized Boride Phases on the Impact Behavior of Iron-Based Composites Reinforced by B4C Particles

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 554
Author(s):  
Fehmi Nair ◽  
Mustafa Hamamcı
Keyword(s):  
Contact Forces ◽  
Impact Behavior ◽  
Iron Matrix ◽  
Impact Tests ◽  
B4c Particles ◽  
Iron Based ◽  
In Situ Reactions ◽  
Boride Phases ◽  
The Impact

The objective of this study is to investigate the impact behavior of iron-based composites reinforced with boron carbide (B4C) particles and in-situ synthesized iron borides (Fe2B/FeB). The composite specimens (Fe/B4C) were fabricated by hot-pressing under a pressure of 250 MPa at 500 °C, and sintered at a temperature of 1000 °C. The effects of the reinforcement ratio on the formation of in-situ borides and impact behavior were investigated by means of different volume fractions of B4C inside the iron matrix: 0% (un-reinforced), 5%, 10%, 20%, and 30%. Drop-weight impact tests were performed by an instrumented Charpy impactor on reinforced and un-reinforced test specimens. The results of the impact tests were supported with microstructural and fractographical analysis. As a result of in-situ reactions between the Fe matrix and B4C particles, Fe2B phases were formed in the iron matrix. The iron borides, formed in the iron matrix during sintering, heavily affected the hardness and the morphology of the fractured surface. Due to the high amount of B4C (over 10%), porosity played a major role in decreasing the contact forces and fracture energy. The results showed that the in-situ synthesized iron boride phases affect the impact properties of the Fe/B4C composites.

Modeling and Analysis of a Ball and Beam System Including Impacts and Dry Friction

2014 ◽  
Author(s):  
Diego Colón ◽  
Átila Madureira Bueno ◽  
Ivando S. Diniz ◽  
Jose M. Balthazar
Keyword(s):  
Differential Inclusion ◽  
Dry Friction ◽  
Viscous Friction ◽  
Mathematical Object ◽  
Contact Forces ◽  
Modeling And Analysis ◽  
Typical Situation ◽  
Beam System ◽  
The Impact ◽  
Ball And Beam System

The Ball and Beam system is a common didactical plant that presents a complex nonlinear dynamics. This comes from the fact that the ball rolls over the beam, which rotates around its barycenter. In order to deduce the system’s equations, composition of movement must be applied, using a non-inertial reference frame attached to the beam. In the Literature, a common hypothesis is to suppose that the ball rolls without slipping. If a viscous friction is supposed to be present, a simpler situation is obtained, where Lagrangean mechanics can be applied, and no contact force is known. Even then, the dynamics is very nonlinear. However, this model does not include all the relevant phenomena, such as ball’s slipping at higher beam’s inclination angles, dry friction between the ball and the beam, and impacts between: 1) the ball and the ends of the beam, and 2) the beam and the base (ground). These additions to the model impose the necessity to calculate, in a simulation setting, the contact forces, and the Newton’s approach to determine the system’s equations becomes more convenient. Also, discontinuities in the model are introduced, and the simpler mathematical object for model such systems are the differential inclusion systems. In this work, we deduce the Ball and Beam differential inclusion system, including dry friction and the impact between the ball and beam. We also present simulation results for the corresponding differential inclusion system in a typical situation.

scholarly journals Estimating Friction Parameters in Reaction Wheels for Attitude Control

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Valdemir Carrara ◽  
Hélio Koiti Kuga
Keyword(s):  
Attitude Control ◽  
Deterministic Model ◽  
High Reliability ◽  
Viscous Friction ◽  
Static Friction ◽  
Friction Model ◽  
Artificial Satellites ◽  
Wide Range ◽  
The Stability ◽  
Friction Parameters

The ever-increasing use of artificial satellites in both the study of terrestrial and space phenomena demands a search for increasingly accurate and reliable pointing systems. It is common nowadays to employ reaction wheels for attitude control that provide wide range of torque magnitude, high reliability, and little power consumption. However, the bearing friction causes the response of wheel to be nonlinear, which may compromise the stability and precision of the control system as a whole. This work presents a characterization of a typical reaction wheel of 0.65 Nms maximum angular momentum storage, in order to estimate their friction parameters. It used a friction model that takes into account the Coulomb friction, viscous friction, and static friction, according to the Stribeck formulation. The parameters were estimated by means of a nonlinear batch least squares procedure, from data raised experimentally. The results have shown wide agreement with the experimental data and were also close to a deterministic model, previously obtained for this wheel. This model was then employed in a Dynamic Model Compensator (DMC) control, which successfully reduced the attitude steady state error of an instrumented one-axis air-bearing table.

Probabilistic Critical Safety Wheel Wear Sizes of Chinese Railway Freight Cars

2008 ◽  
Vol 44-46 ◽  
pp. 759-764
Author(s):  
Yong Xiang Zhao ◽  
Bing Yang ◽  
Ming Fei Feng ◽  
Y. Li ◽  
M.J. Liu ◽  
...  
Keyword(s):  
Field Investigation ◽  
State Equation ◽  
Contact Forces ◽  
Hertzian Contact ◽  
Wheel Wear ◽  
Size Change ◽  
Railway Freight ◽  
Impact Forces ◽  
Safety Effect ◽  
The Impact

Critical safety wheel wear size is investigated through considering the fatigue safety effect on RD2 type axle of China railway freight cars. The wheel wear size increase results in a rise of the wheel-rail contact forces, which increase the fatigue stress history of the axle in service. Therefore, the size must be controlled to maintain the axle safety in service before the next overhaul inspection. A field investigation was firstly made on the wear size change regularity. Then, the size related wheel-rail impact forces are solved by a non-linear Hertzian contact theory with a vehicle multi-body dynamic model. In addition, a statistical method is further developed for incorporating the impact forces into the wheelset service load history. Finally, a wear size related critical state equation is established for ensuring the axle safety in service. A stationary solution is statistically obtained for the critical wear sizes with respect to the axle circumferential crack and semi-elliptical crack. It is concluded that the critical safety wear size should be controlled in the range of 100 mm at the statistical level of survival probability 0.99 and confidence 95%.

scholarly journals Simulation of Low Velocity Impact on Composite Hemispherical Shell

2014 ◽  
Vol 564 ◽  
pp. 406-411
Author(s):  
Parnia Zakikhani ◽  
R. Zahari ◽  
Mohamed Thariq Hameed Sultan
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Experimental Testing ◽  
Low Velocity Impact ◽  
Impact Behavior ◽  
Low Velocity ◽  
Element Analysis ◽  
Velocity Impact ◽  
Hemispherical Shell ◽  
The Impact

Impact simulation with finite element analysis is an appropriate manner to reduce the cost and time taken to carry out an experimental testing on a component. In this study, the impact behavior of the composite hemispherical shell induced by low velocity impact is simulated in ABAQUS software with finite element method. To predict the responses of Kevlar fabric/polyester, glass fabric/polyester and carbon fabric/polyester in the form of a hemisphere, once as one layer and then as a three-layered composite under applied force by an anvil. The sequences of layers are changed, to investigate and compare the occurred alternations in the amount of energy absorption, impact force and specific energy absorption (SEA). The comparison of results showed that the highest and the lowest quantity of energy absorption and SEA belong to Carbon/Glass/Kevlar (CGK) and Kevlar/Carbon/Glass (KCG) respectively.

scholarly journals Finite Element Analysis of Load Bearing Capacity of a Reinforced Concrete Frame Subjected to Cyclic Loading

2016 ◽  
Vol 2 (5) ◽  
pp. 221-225 ◽  
Author(s):  
Mahdi Bamdad ◽  
Abdolreza Sarvghad Moghadam ◽  
Mohammad Javad Mehrani
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Impact Behavior ◽  
Reinforced Concrete Frame ◽  
Load Bearing Capacity ◽  
Element Analysis ◽  
Load Bearing ◽  
Concrete Frame ◽  
The Impact ◽  
Abaqus Software

Many methods have been developed in order to study the impact behavior of solids and structures. Two common methods are finite element and experimental method. The nonlinear finite element method is one the most effective methods of predicting the behavior of RC beams from zero-load to failure and its fracture, yield and ultimate strengths. The advantage of this method is its ability to make this prediction for all sections of the assessed RC beam and all stages of loading. This paper compares the experimental results obtained for a RC frame with the numerical results calculated by ABAQUS software, and plots both sets of results as hysteresis–displacement diagrams. This comparison shows that the numerical FEM implemented via ABAQUS software produce valid and reliable results for load bearing capacity of RC frames subjected to cyclic loads, and therefore has significant cost and time efficiency advantages over the alternative approach

Multiaxial Impact Behavior and Modeling of ABS Polymer

2001 ◽  
Author(s):  
A. Saigal ◽  
R. Greif ◽  
Y. Duan ◽  
M. A. Zimmerman
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Rate ◽  
Impact Load ◽  
Mechanical Test ◽  
Impact Behavior ◽  
Analysis Model ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
The Impact

Abstract The multiaxial impact behavior of CYCOLAC GPM5500 (ABS glassy polymer) is obtained as a function of impact velocity and temperature from the standard impact test as specified by ASTM D3763. Finite element analysis (FEA) and ABAQUS/Explicit are used to model the impact behavior of the polymer. The generalized “DSGZ” constitutive model, previously developed by the authors and calibrated using low strain rate uniaxial mechanical test data, is extended to the high strain rate regime and used in the finite element analysis. Load-displacement curves from the finite element analysis are compared with the experimental data and agree well up to the maximum impact load (failure). Therefore, the proposed finite element analysis model can be used to predict the multiaxial impact behaviors of polymers at different temperatures and impact velocities.

scholarly journals FEM Analysis of Textile Reinforced Composite Materials Impact Behavior

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7380
Author(s):  
Savin Dorin Ionesi ◽  
Luminita Ciobanu ◽  
Catalin Dumitras ◽  
Manuela Avadanei ◽  
Ionut Dulgheriu ◽  
...  
Keyword(s):  
Composite Materials ◽  
Impact Resistance ◽  
Fem Analysis ◽  
Impact Behavior ◽  
Time Interval ◽  
Short Time Interval ◽  
Element Analysis ◽  
Textile Reinforced Composite ◽  
And Behavior ◽  
The Impact

Composite materials reinforced with textile fabrics represent a complex subject. When explaining these materials, one must consider their mechanical behavior in general, and impact resistance in particular, as many applications are characterized by dynamic strains. Impact characteristics must be considered from the early stages of the design process in order to be controlled through structure, layer deposition and direction. Reinforcement materials are essential for the quality and behavior of composites, and textile reinforcements present a large range of advantages. It takes a good understanding of the requirements specific to an application to accurately design textile reinforcements. Currently, simulations of textile reinforcements and composites are efficient tools to forecast their behavior during both processing and use. The paper presents the steps that must be followed for modelling the impact behavior of composite materials, using finite element analysis (FEM). The FEM model built using Deform 3D software offers information concerning the behavior structure during impact. The behavior can be visualized for the structure as a whole and, for different sections, be considered significant. Furthermore, the structure’s strain can be visualized at any moment. In real impact tests, this is not possible due to the very short time interval and the impossibility to record inside the structure, as well as to record all significant stages using conventional means.

Friction and the Inverted Pendulum Stabilization Problem

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Sue Ann Campbell ◽  
Stephanie Crawford ◽  
Kirsten Morris
Keyword(s):  
Small Amplitude ◽  
Viscous Friction ◽  
Experimental System ◽  
Linear Quadratic Regulator ◽  
Poor Performance ◽  
Friction Model ◽  
Linear Quadratic ◽  
Stick Slip ◽  
And Performance ◽  
Friction Parameters

We consider an experimental system consisting of a pendulum, which is free to rotate 360deg, attached to a cart. The cart can move in one dimension. We study the effect of friction on the design and performance of a feedback controller, a linear quadratic regulator, that aims to stabilize the pendulum in the upright position. We show that a controller designed using a simple viscous friction model has poor performance—small amplitude oscillations occur when the controller is implemented. We consider various models for stick slip friction between the cart and the track and measure the friction parameters experimentally. We give strong evidence that stick slip friction is the source of the small amplitude oscillations. A controller designed using a stick slip friction model stabilizes the system, and the small amplitude oscillations are eliminated.

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