This paper deals with detennination of macroscopic fracture characteristics of random panicle systems. which represents a fundamental but little explored problem of micromechanics of quasibrittle materials. The panicle locations are randomly generated and the mechanical properties are characterized by a triangular softening forcedisplacement diagram for the interparticle links. An efficient alg...

Machining is a complex process that requires a high degree of precision with tight geometrical tolerance and surface finish. Those are confronted by the existence of vibration in the turning machine tool. Overcoming a micro level vibration of a cutting tool using smart materials can save old machines and enhance flexibility in designing new generations of machine tools. Using smart materials to...

This article presents two applications of the nonlinear finite element analysis (FEA) using ABAQUS/Standard with a user developed material subroutine Nitinol UMAT from Abaqus West. The analyses are found to agree well with the theoretical prediction and/or experimental measurement. In that first example, FEA predicts the stress-strain response of a superelastic Nitinol device at different Af te...

The main objective of the paper is to demonstrate the computer simulation and energy absorption of tapered tubes under impact load. The study of the impact load includes axial compression, bending and torsion. In general, one could rely on the use of finite element analysis to determine the energy absorption capacity of the energy absorbers. This tool is helpful and accuracy. The parametric var...

In this paper, thermal conductivity of crystalline GaAs is calculated using first-principles lattice dynamics. The harmonic and cubic force constants are obtained by fitting them to the forcedisplacement data from density functional theory calculations. Phonon dispersion is calculated from dynamical matrix constructed using the harmonic force constants and phonon relaxation times are calculated...

This paper presents the procedure and results of two experiments dealing with the force resolution of the human finger and with haptic demands on push-buttons. The outcome is used to specify design details of a novel approach to a flexible control panel. A haptic display controlled by a PC enables the simulation of push-buttons with programmable forcedisplacement curves. The “just noticeable fo...

We describe studies of the elastic properties and frictional characteristics of graphene samples of varying thickness using an atomic force microscope. For tensile testing, graphene is suspended over micron-sized circular holes and indented by atomic force microscope (AFM) tips. Fitting of the forcedisplacement curves yields the prestress and elastic stiffness, while comparison of the breaking ...

Surgical simulation is a field that shows much promise in terms of permitting surgeons to learn new skills, as well as enabling the development of new procedures and instruments while minimizing the use of animal subjects. Essential to simulation with realistic force feedback are material property data for the wide variety of soft tissues, both in healthy and diseased conditions. Properties are...

Novel designs of an array of piezoelectric stack actuators using a unique buckling mechanism are presented in this paper. Multiple PZT actuator units with high gain displacement amplification mechanisms are arranged in parallel with spatial phase differences. Having an inherent kinematic singularity, the buckling mechanism provides not only an extremely high gain of displacement amplification, ...