Influence of Contact Friction Conditions on Thin Profile Simulation Accuracy in Extrusion

2011 ◽  
Vol 491 ◽  
pp. 35-42 ◽  
Author(s):  
Sergey Stebunov ◽  
Nikolay Biba ◽  
Andrey Lishnij
Keyword(s):  
Material Flow ◽  
Element Model ◽  
Friction Model ◽  
Contact Friction ◽  
Good Correspondence ◽  
Simulation Accuracy ◽  
Complex Shapes ◽  
Friction Models ◽  
Series Of Experiments ◽  
Aluminium Extrusion

The paper presents the development of the Finite Element model for simulation of thin aluminium profile extrusion of both solid and hollow shapes. The analysis has shown that the material flow in simulation is very dependent on the friction model. Experimental and theoretical studies show that friction traction on the interface between the tool and the deformed material can be represented as a combination of adhesive friction force and the force that is required to deform surface asperities. In aluminium extrusion we can clearly distinguish two different areas with respect to friction conditions such as sticking and sliding and transient zones between them. The lengths of these zones are also dependent on variation of the choke angle and actual thickness of the profile. To get these values the material flow problem is to be coupled with the simulation of the tools deformation. A series of experiments with specially designed tools have been done to investigate how the bearing length and choke angle may influence the extension of different friction zones and by these means vary the material flow pattern. The friction models have also been tested with industrial profiles of complex shapes and have shown good correspondence to reality.

A new friction model for the slide guide in elevator systems: Experimental and theoretical investigations

2008 ◽  
Vol 222 (11) ◽  
pp. 2177-2189 ◽  
Author(s):  
X G Zhang ◽  
K J Guo ◽  
H G Li ◽  
G Meng
Keyword(s):  
Time Lag ◽  
Friction Model ◽  
Dynamical Analysis ◽  
Contact Friction ◽  
Proposed Model ◽  
Theoretical Investigations ◽  
Friction Models ◽  
Design And Manufacture ◽  
Sliding Regimes

In the design and manufacture of elevator systems, the slide guide in elevators moves in contact against the guide rail. This kind of surface contact exhibits a highly non-linear hysteretic friction behaviour, which hampers the riding quality of the elevator systems to a great extent. First, this paper presents an experimental investigation on this type of phenomenon through the measurement of contact friction force between the interface of the slide guide and the rail under different combinations of input parameters. The experiment clearly shows various types of frictional behaviour, including presliding/gross-sliding regimes, the transition behaviour between them, friction overshoot, time lag, velocity (weakening and strengthening) dependence, etc. In addition, it is found that for different materials in contact, lubrication conditions and friction duration have strong impacts on the evaluation of their friction characteristics. Based on the observations of this test, an improved friction model derived from the Bouc—Wen model is then proposed and compared with other friction models. The Bouc—Wen model is improved by adding elements considering the velocity dependence and friction overshoot. The numerical simulations show that the proposed model can capture the behaviour found in the experiments, agrees with the experimental data reasonably well, and may be used for the dynamical analysis of the elevator systems.

Modeling of Piezo-Actuated Stick-Slip Micro-Drives: An Overview

2012 ◽  
Vol 81 ◽  
pp. 39-48 ◽  
Author(s):  
Ha Xuan Nguyen ◽  
Christoph Edeler ◽  
Sergej Fatikow
Keyword(s):  
Mechanical Model ◽  
Integrated Model ◽  
Friction Model ◽  
Fundamental Importance ◽  
Future Research ◽  
Stick Slip ◽  
Research Activities ◽  
Model Combining ◽  
Friction Models

This paper gives an overview about problems of modeling of piezo-actuated stick-slip micro-drives. It has been found that existing prototypes of such devices have been investigated empirically. There is only few research dealing with the theory behind this kind of drives. By analyzing the current research activities in this field, it is believed that the model of the drive depends strongly on the friction models, but in most cases neglecting any influences of the guilding system.These analyses are of fundamental importance for an integrated model combining friction model and mechanical model offering promising possibilities for future research.

The Effect of Tool Geometrical Parameters on Cutting Temperature Based on Deform-3D

2013 ◽  
Vol 690-693 ◽  
pp. 2554-2558
Author(s):  
Hua Jing Zhang ◽  
Zhi Tao Tang
Keyword(s):  
Finite Element ◽  
Imaging System ◽  
Cutting Temperature ◽  
Element Model ◽  
Friction Model ◽  
Geometrical Parameters ◽  
Infrared Thermal Imaging ◽  
Temperature Filed ◽  
Thermal Imaging System ◽  
Key Techniques

The finite element method was adopted to predict the cutting temperature filed of workpiece surface when machining aerospace aluminum alloy 7050-T7451. Some key techniques such as the materials flow stress behavior, the separation of the chips with the workpiece, failure and fracture criterion, the tool-chip friction model were discussed in details. To validate the finite element model, the cutting temperature field of the chip was obtained by infrared thermal imaging system. The result revealed that the prediction model is credible. Based on the model, the effects of tool geometrical parameters such as flank wear, cutting edge inclination and corner radius on cutting temperature were analyzed.

Study on the Deformation of the Oil-Immersed Transformer Tank by FEA

2011 ◽  
Vol 422 ◽  
pp. 51-54 ◽  
Author(s):  
Jian Hua Zhang ◽  
Ling Yu Sun ◽  
Xiao Jun Zhang ◽  
Jia Peng Li
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Mechanical Strength ◽  
Element Model ◽  
3D Finite Element ◽  
3D Finite Element Model ◽  
Series Of Experiments ◽  
Oil Tank ◽  
Directive Function

The oil-immersed transformer tank is an outside package component of the transformer body. The sealing quality and mechanical strength of the oil tank are affected by the deformation after loading. In this paper, the 3D finite element model of oil-immersed transformer tank is established. The oil-immersed transformer tank deformation is obtained by FEA under the condition of vacuuming. A series of experiments about the deformation of the oil-immersed transformer tank are carried out. Comparing experiment results with FEA results, FEA results are agrees well with the experiments’. It can save the time consumed on designing the oil tank, and has the directive function for the whole design.

scholarly journals An Efficient Contact Model for the Simulation of Cargo Airdrop Extraction Phase

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Leiming Ning ◽  
Jichang Chen ◽  
Mingbo Tong
Keyword(s):  
Degrees Of Freedom ◽  
Friction Model ◽  
Rigid Bodies ◽  
Contact Dynamics ◽  
Moving Frame ◽  
Contact Friction ◽  
Practical Implementation ◽  
Contact Formulation ◽  
Efficient Code ◽  
Extraction Phase

A high-fidelity cargo airdrop simulation requires the accurate modeling of the contact dynamics between an aircraft and its cargo. This paper presents a general and efficient contact-friction model for the simulation of aircraft-cargo coupling dynamics during an airdrop extraction phase. The proposed approach has the same essence as the finite element node-to-segment contact formulation, which leads to a flexible, straightforward, and efficient code implementation. The formulation is developed under an arbitrary moving frame with both aircraft and cargo treated as general six degrees-of-freedom rigid bodies, thus eliminating the restrictions of lateral symmetric assumptions in most existing methods. Moreover, the aircraft-cargo coupling algorithm is discussed in detail, and some practical implementation details are presented. The accuracy and capability of the present method are demonstrated through four numerical examples with increasing complexity and fidelity.

Comparison of Four Friction Models: Feature Prediction

2015 ◽  
Vol 11 (3) ◽  
Author(s):  
Yun-Hsiang Sun ◽  
Tao Chen ◽  
Christine Qiong Wu ◽  
Cyrus Shafai
Keyword(s):  
Numerical Model ◽  
Viscous Friction ◽  
Friction Model ◽  
Dynamic Features ◽  
Numerical Predictions ◽  
Wide Range ◽  
Model Predictions ◽  
Friction Models ◽  
Parameter Identifications ◽  
Model Structures

In this paper, we provide not only key knowledge for friction model selection among candidate models but also experimental friction features compared with numerical predictions reproduced by the candidate models. A motor-driven one-dimensional sliding block has been designed and fabricated in our lab to carry out a wide range of control tasks for the friction feature demonstrations and the parameter identifications of the candidate models. Besides the well-known static features such as break-away force and viscous friction, our setup experimentally demonstrates subtle dynamic features that characterize the physical behavior. The candidate models coupled with correct parameters experimentally obtained from our setup are taken to simulate the features of interest. The first part of this work briefly introduces the candidate friction models, the friction features of interest, and our experimental approach. The second part of this work is dedicated to the comparisons between the experimental features and the numerical model predictions. The discrepancies between the experimental features and the numerical model predictions help researchers to judge the accuracy of the models. The relation between the candidate model structures and their numerical friction feature predictions is investigated and discussed. A table that summarizes how to select the most optimal friction model among a variety of engineering applications is presented at the end of this paper. Such comprehensive comparisons have not been reported in previous literature.

A Comparison of Two Microslip Contact Models for Studying the Mechanics of Underplatform Dampers

2018 ◽  
Author(s):  
Chao Xu ◽  
Dongwu Li ◽  
Muzio M. Gola ◽  
Chiara Gastaldi
Keyword(s):  
Friction Coefficient ◽  
Friction Model ◽  
Tangential Displacement ◽  
Tangential Stiffness ◽  
Contact Loads ◽  
Contact Kinematics ◽  
Contact Models ◽  
Friction Models ◽  
Microslip Friction ◽  
Contact Parameters

In turbine blade systems, under-platform dampers are widely used to attenuate excessive resonant vibrations. Subjected to vibration excitation, the components with frictionally constrained interfaces can involve very complex contact kinematics induced by tangential and normal relative motions. To effectively calculate the dynamics of a blade-damper system, contact models which can accurately reproduce the interface normal and tangential motions are required. The large majority of works have been developed using macroslip friction models to model the friction damping at the contact interface. However, for those cases with small tangential displacement where high normal loads are applied, macroslip models are not enough to give accurate results. In this paper two recently published microslip models are compared, between them and against the simple macroslip spring-slider model. The aim is to find to which extent these models can accurately predict damper mechanics. One model is the so called GG array, where an array of macroslip elements is used. Each macroslip element of the GG array is assigned its own contact parameters and for each of them four parameters are needed: normal stiffness, tangential stiffness, normal gap and friction coefficient. The other one is a novel continuous microslip friction model. The model is based on a modification of the original classic IWAN model to couple normal and tangential contact loads. Like the GG array the model needs normal and tangential stiffness, and friction coefficient. Unlike the GG array the model is continuous and, instead of the normal gap required by the GG array, the Modified IWAN model needs a preload value. The two models are here applied to the study of the mechanics of a laboratory under-platform damper test rig. The results from the two models are compared and allow their difference, both for damper mechanics and for the complex-spring coefficients, to be assessed.

scholarly journals Sketch Based Image Deformation and Editing with Guaranteed Feature Correspondence

2012 ◽  
Vol 11 (1) ◽  
pp. 25-32
Author(s):  
Yaqiong Liu ◽  
Seah Hock Soon ◽  
Ying He ◽  
Juncong Lin ◽  
Jiazhi Xia
Keyword(s):  
Unit Circle ◽  
Delaunay Triangulation ◽  
Shape Deformation ◽  
Feature Correspondence ◽  
Good Correspondence ◽  
Image Deformation ◽  
Target Shape ◽  
Feature Lines ◽  
Complex Shapes ◽  
Correspondence Mapping

The establishment of a good correspondence mapping is a key issue in planar animations such as image morphing and deformation. In this paper, we present a novel mapping framework for animation of complex shapes. We firstly let the user extract the outlines of the interested object and target interested area from the input images and specify some optional feature lines, and then we generate a sparse delaunay triangulation mesh taking the outlines and the feature lines of the source shape as constraints. Then we copy the topology from the source shape to the target shape to construct a valid triangulation in the target shape. After that, each triangle of this triangular mesh is further segmented into a dense mesh patch. Each mesh patch is parameterized onto a unit circle domain. With such parametrization, we can easily construct a correspondence mapping between the source patches and the corresponding target patches. Our framework can work well for various applications such as shape deformation and morphing. Pleasing results generated by our framework show that the framework works well.

Current-Dependent Dynamics of Bidirectional Self-Folding for Multi-Layer Polymers Using Local Resistive Heating

2021 ◽  
Vol 143 (3) ◽  
Author(s):  
Moataz Elsisy ◽  
Evan Poska ◽  
Moataz Abdulhafez ◽  
Mostafa Bedewy
Keyword(s):  
Material Flow ◽  
Shape Memory Polymer ◽  
Three Dimensional ◽  
Element Model ◽  
Lightweight Structures ◽  
Local Material ◽  
Polymer Sheets ◽  
New Process ◽  
Origami Engineering

Abstract The purpose of this paper is to characterize the dynamics and direction of self-folding of pre-strained polystyrene (PSPS) and non-pre-strained styrene (NPS), which results from local shrinkage using a new process of directed self-folding of polymer sheets based on a resistively heated ribbon that is in contact with the sheets. A temperature gradient across the thickness of this shape memory polymer (SMP) sheet induces folding along the line of contact with the heating ribbon. Varying the electric current changes the degree of folding and the extent of local material flow. This method can be used to create practical three-dimensional (3D) structures. Sheets of PSPS and NPS were cut to 10 × 20 mm samples, and their folding angles were plotted with respect to time, as obtained from in situ videography. In addition, the use of polyimide tape (Kapton) was investigated for controlling the direction of self-folding. Results show that folding happens on the opposite side of the sample with respect to the tape, regardless of which side the heating ribbon is on, or whether gravity is opposing the folding direction. The results are quantitatively explained using a viscoelastic finite element model capable of describing bidirectional folds arising from the interplay between viscoelastic relaxation and strain mismatch between polystyrene and polyimide. Given the tunability of fold times and the extent of local material flow, resistive-heat-assisted folding is a promising approach for manufacturing complex 3D lightweight structures by origami engineering.

scholarly journals Validation of Friction Model Parameters Identified Using the IHB Method Using Finite Element Method

2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Abdallah Hadji ◽  
Njuki Mureithi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Friction Force ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Friction Model ◽  
Balance Method ◽  
Model Parameters ◽  
Friction Models ◽  
Element Method

A hybrid friction model was recently developed by Azizian and Mureithi (2013) to simulate the friction behavior of tube-support interaction. However, identification and validation of the model parameters remains unresolved. In previous work, the friction model parameters were identified using the reverse harmonic method, where the following quantities were indirectly obtained by measuring the vibration response of a beam: friction force, sliding speed of the force of impact, and local displacement at the contact point. In the present work, the numerical simulation by the finite element method (FEM) of a beam clamped at one end and simply supported with the consideration of friction effect at the other is conducted. This beam is used to validate the inverse harmonic balance method and the parameters of the friction models identified previously. Two static friction models (the Coulomb model and Stribeck model) are tested. The two models produce friction forces of the correct order of magnitude compared to the friction force calculated using the inverse harmonic balance method. However, the models cannot accurately reproduce the beam response; the Stribeck friction model is shown to give the response closest to experiments. The results demonstrate some of the challenges associated with accurate friction model parameter identification using the inverse harmonic balance method. The present work is an intermediate step toward identification of the hybrid friction model parameters and, longer-term, improved analysis of tube-support dynamic behavior under the influence of friction.

Sign in / Sign up

Export Citation Format

Share Document