The discretization by finite elements of a model variational problem for a clamped loaded beam is studied with emphasis on the effect of the beam thickness, which appears as a parameter in the problem, on the accuracy. It is shown that the approximation achieved by a standard finite element method degenerates for thin beams. In contrast a large family of mixed finite element methods are shown t...

Abstract The procedure presented in this work aims at providing a framework for studying settlement of ballast zones with stiffness variation the railway track support. proposed results from expanding an existing infinite periodic model to account variations foundation. Ballast is simulated via linear lattice, whose dynamic response differs that continuum. expanded composed three regions: left ...

in the current study, the effects of interactions of the moving loads and the attached mass-spring-damper systems of the composite plates on the resulting dynamic responses are investigated comprehensively, for the first time, using the classical plate theory. the solution of the coupled governing system of equations is accomplished through tracing the spatial variations using a navier-type sol...

In this paper, a finite element (FE) modeling is used to model effects of the arterial stiffness on the different signal patterns of the pulse transit time (PTT). Several different breathing patterns of the three subjects are measured with PTT signal and corresponding finite element model of the straight elastic artery is applied. The computational fluid-structure model provides arterial elasti...

In the assessment of fracture healing by monitoring stiffness with vibrational analysis or instrumented external fixators, it has been assumed that there is a workable correlation between stiffness and strength. We used four-point bending tests to study time-related changes in stiffness and strength in healing tibial fractures in sheep. We aimed to test the validity of the measurement of stiffn...

It is widely known that the pinch-grip forces of the human hand are linearly related to the weight of the grasped object. Less is known about the relationship between grip force and grip stiffness. We set out to determine variations to these dependencies in different tasks with and without visual feedback. In two different settings, subjects were asked to (a) grasp and hold a stiffness-measurin...

Railway transition zones between open track and rigid structures such as bridges and culverts often experience differential movements due to abrupt changes in track stiffness and complicated dynamic loading effects. Such conditions commonly lead to track geometry issues, consequently increasing the magnitude of impact loads at these areas. This in turn leads to excessive degradation of ballast ...

In this article, we address the problem of controlling unknown flexible-joint robots with unknown time-varying stiffness and damping parameters. We propose a Robust Direct Adaptive Fuzzy Control (RDAFC) strategy that accommodates the dynamics anonymity and joints stiffness/damping variations. The RDAFC strategy relies on the synergy of the concepts of fuzzy logic approximation and the Sliding M...

Abstract. The characterization of flexible joints robotic underactuated fingers allows the investigation finger flexion trajectories using a tendon-driven actuation. In this paper, TPU 3D printed used in fingers, is experimentally and numerically performed. Since mechanical properties materials are uncertain, research helps to define characteristics terms stiffness. role stiffness for control f...

Helical springs within the primary suspension are critical components for isolating the whole vehicle system from vibration generated at the wheel/rail contact. As train speeds increase, the frequency region of excitation becomes larger, and a simplified static stiffness can no longer represent the real stiffness property in a vehicle dynamic model. Coil springs in particular exhibit strong int...