Abstract The effects of long-term Functional Electrical Stimulation (FES) assisted walking on ankle dynamic stiffness were examined in spinal cord injured (SCI) subjects with incomplete motor function loss. A parallelcascade system identification method was used to identify intrinsic and reflex contributions to dynamic ankle stiffness at different positions with subjects instructed to remain re...

As a popular controller used in the industrial servo drives, the pseudo derivative feedback with feedforward (PDFF) scheme has 3 parameters for tuning to achieve a good trade-off design between tracking and dynamic stiffness. However, the two parameters in the feedback path of the PDFF controller are restricted to constant for design simplicity that limits its dynamic stiffness. This paper pres...

in the present study, a spectral finite element method is developed for free and forced transverse vibration of levy-type moderately thick rectangular orthotropic plates based on first-order shear deformation theory. levy solution assumption was used to convert the two-dimensional problem into a one-dimensional problem. in the first step, the governing out-of-plane differential equations are tr...

Genetic progress in reducing eggshell damage depends on having a measurement that can both predict if an egg will crack during routine handling and whose variance contains a substantial genetic component. We have demonstrated that the measurement of dynamic stiffness, derived from the acoustic resonance of the egg and its mass, fulfils both of these criteria. The heritability of dynamic stiffne...

a frequency domain dynamic analysis is needed to obtain the response of structures constructed on a system of base isolators on flexible soil when subjected to earthquake ground motion. in such systems, the lateral stiffness of the base isolators is so small, compared to the structural stiffness, that in an earthquake attack the fundamental vibration mode dominates the response. with this in mi...

The dynamic performance of structures under traveling loads should be exactly analyzed to have a safe and reasonable structural design. Different higher-order shear deformation theories are proposed in this paper to analyze the dynamic stability of thick elastic plates carrying a moving mass. The displacement fields of different theories are chosen based upon variations along the thickness as c...

Temperature has an influence on damping characteristics of the viscoelastic damping structure. The change of the damping characteristics of the structure under the cycle load is a dynamic and coupled process. The hyperelastic-viscoelastic model was used to describe nonlinear deformation and viscoelasticity simultaneously. The temperature distribution and change of the damping characteristics un...

In this paper, forced vibration analysis of a single-layered graphene sheet (SLGS) under moving a nanoparticle is carried out using the non-local elasticity theory of orthotropic plate. The SLGS under moving the nanoparticle is placed in the elastic and viscoelastic foundation which are simulated as a Pasternak and Visco-Pasternak medium, respectively. Movement of the nanoparticle is considered...

This paper proposes an efficient and reliable eigenvalue solution technique for analytical stochastic dynamic stiffness (SDS) formulations of beam built-up structures with parametric uncertainties. The SDS are developed based on frequency-dependent shape functions in conjunction both random-variable random-field structural parameters. overall numerical framework is aimed towards representing th...