The paper focuses on the accuracy improvement of stiffness models for parallel manipulators, which are employed in high-speed precision machining. It is based on the integrated methodology that combines analytical and numerical techniques and deals with multidimensional lumped-parameter models of the links. The latter replace the link flexibility by localized 6-dof virtual springs describing bo...

Particulate composites with negative stiffness inclusions in a viscoelastic matrix are shown to have higher thermal expansion than that of either constituent and exceeding conventional bounds. It is also shown theoretically that other extreme linear coupled field properties including piezoelectricity and pyroelectricity occur in layerand fiber-type piezoelectric composites, due to negative incl...

Abstract. The dynamic load-sharing characteristics of aircraft face gear dual-power split transmission system (FGDPSTS) are taken as the research object. Considering factors time-varying meshing stiffness, comprehensive error, backlash, support clearance, spline torsional and model was constructed based on lumped-parameter method. loaded tooth contact analysis (LTCA) simulation method used to c...

Most research papers about parallel kinematic chain mechanisms investigate symmetric robot manipulators, in which all the limbs connecting the end-effector to the fixed based are composed by the same sequence of links and joints. Contrarily, in some manipulation tasks the velocity and stiffness requirements are anisotropic. In such cases, the asymmetric parallel kinematic chain mechanisms may o...

A 60 years old female patient suffering from neck stiffness with solid irregular anterior neck lump came to ultrasound clinic of Radiation and Isotope Centre of Khartoum (RICK), longitudinal and transverse ultrasound scan (U/S) was done for her both thyroid lobes; ultrasound results showed huge (Rt) thyroid lobe nodule with typical criteria's of malignant nodules (solid , solitary , irregular a...

We evaluated whether lumped-parameter non-linear viscoelastic models of human fingertip tissue can describe fingertip force-displacement characteristics during a range of rapid, dynamic tapping tasks. Eight human subjects tapped with their index finger on the surface of a rigid load cell while an optical system tracked fingertip position using an infra-red LED attached to the fingernail. Four d...

In recent times, vibration based energy harvesting has drawn attention of many researchers worldwide. This is due to advancement in Microelectromechanical (MEM) devices and wireless sensors with power requirements in range of microwatts-milliWatts; hence vibration energy sources have promising potentials for such demands. Thus, many attempts were made by researchers to develop different system ...

In this study, a lumped compartment cardiovascular model is developed to predict pulsatile pressures in the systemic and pulmonary circulation as well as in finger arteries. Essential compartments of the model include arterial and venous pulmonary, left and right ventricles, and arterial and venous systemic compartments. A pulsatile left ventricle is incorporated to be the source of pulse waves...

This paper presents a new method for efficiently and accurately modeling the elasto-kinematic behaviors of torsion beam suspension systems and of other similar classes of mechanical systems, and a design method utilizing the models. The torsion beam is represented as a linkage of lumped mass joined by nonlinear springs, bending and torsion, whose stiffness are identified via off-line computatio...