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Dynamic Deformation (dynamic + deformation)

Distribution by Scientific Domains

Polymers and Materials Science	50%
Engineering	33%

Selected Abstracts

MATERIAL AND CONSTRUCTION CHANGES INFLUENCE ON A TIRE DYNAMIC DEFORMATION

EXPERIMENTAL TECHNIQUES, Issue 3 2009
M. Mokry
First page of article [source]

Coupled simulation of wave propagation and water flow in soil induced by high-speed trains

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 11 2008
P. Kettil
Abstract The purpose of this paper is to simulate the coupled dynamic deformation and water flow that occur in saturated soils when subjected to traffic loads, which is a problem with several practical applications. The wave propagation causes vibrations leading to discomfort for passengers and people in the surroundings and increase wear on both the vehicle and road structure. The water flow may cause internal erosion and material transport in the soil. Further, the increased pore water pressure could reduce the bearing capacity of embankments. The saturated soil is modelled as a water-saturated porous medium. The traffic is modelled as a number of moving wheel contact loads. Dynamic effects are accounted for, which lead to a coupled problem with solid displacements, water velocity and pressure as primary unknowns. A finite element program has been developed to perform simulations. The simulations clearly demonstrate the induced wave propagation and water flow in the soil. The simulation technique is applicable to railway as well as road traffic. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Ionic polymer-metal composites as multifunctional materials

POLYMER COMPOSITES, Issue 1 2003
Mohsen Shahinpoor
This paper presents a description and a set of experimental results on Ionic Polymer-Metal Composites (IPMC's) as dynamic sensors, transducers, and actuators. Strips of IPMC can exhibit large dynamic deformation if placed in a time-varying electric field of the order of 10's of volts/mm. Conversely, dynamic deformation and flexing of such ionic polymers produces dynamic electric fields that closely follow the form of the electric signal. The underlying principle of such a mechanoelectric effect in IPMC's can be explained by the linear irreversible thermodynamics in which ion and solvent transport are the fluxes and electric field and solvent pressure gradient are the forces. Important parameters include the material conductance and the solvent permeability. The dynamic sensing, transduction, and actuation responses of a strip of IPMC under an impact-type loading is also discussed. When a cantilever strip of IPMC is flipped, a damped oscillatory electric response is produced across a pair of electrodes placed at the cantilever of the strip, which is highly repeatable with a broad frequency range above 104 Hz. Such direct mechanoelectric responses of IMPC's are related to the endo-ionic mobility due to stresses imposed. Imposition of a finite solvent flux without allowing a current flux causes the material to create a certain conjugate electric field that can be dynamically monitored and measured. IPMC's are shown to be highly capacitive at low frequencies while they are highly resistive under high frequency excitations. IN a sending mode, IPMC strips can also sense chemical environments and humidity. These types of sensors/transducers/actuators conceivably can replace piezoresistive and piezoelectric sensors with just one sensor for broad ranges of frequencies. [source]

Interactive soft-touch dynamic deformations

COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3 2007
Hui Chen
Abstract It is crucial for the users to touch, grasp and manipulate the interested objects through our sense of touch in many interactive applications, such as on-line computer games, interactive cartoon design, and virtual prototyping. In this paper, we propose an interactive haptic deformation approach which incorporates the dynamic simulation of mass,spring systems and flexible control of free-form deformation in the touch-enabled soft-object deformation. Through distributing mass, spring and damping coefficients of the object to the bounded Bezier volume lattice, the deformation of the object related to the haptic avatar follows the physical laws and has high working rate. Both homogenous and inhomogenous materials are simulated. The anchor nodes of haptic input are specified to create amazing special effects during the interactive haptic deformation. Interactive haptic deformations of three-type tropic fishes, Angel, Demekin, and GuppyBlueGrass, have been experimented to simulate vivid fish swimming processes in the virtual ocean scene. Our proposed approach provides touch-enabled input and efficient performance in the flexible deforming controls, letting the objects move in a dynamic, cartoon-style deforming manner. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Linear and nonlinear melt-state viscoelastic properties of polypropylene/organoclay nanocomposites

POLYMER ENGINEERING & SCIENCE, Issue 7 2008
Ehssan Nazockdast
Rheological behavior of polypropylene (PP)/organoclay nanocomposites varying in compatibilizer (PP- g -MA) and organoclay concentration was investigated. The samples were prepared by melt intercalation method in an internal mixer. The wide angle X-ray diffraction patterns and results of rheological measurements showed that the compatibilizer had strong influence in increasing the interlayer spacing. The observed low frequency liquid-like to solid-like transition and apparent yield stress in simple shear flows, along with convergence of transient shear stress to nonzero values in stress relaxation after the cessation of flow experiments, were found to be consistent with formation of a physical network in quiescent conditions which could be easily ruptured with applying low shear rates. The values of stress overshoot strain in flow reversal experiments were independent of shear rate, organoclay, and compatibilizer content. From the results of frequency sweep experiments in different nonlinear strain amplitudes it was shown that extended Cox-Merz analogy was valid in nonlinear dynamic deformations while the shear viscosity showed positive deviation from this analogy with higher deviations at lower shear rates. Results of storage modulus recovery and flow reversal experiments at different shear rates suggested that network structure is reformed with a much slower rate compared to the rotational relaxation of organoclay platelets. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source]