In recent years, underactuated nonlinear dynamic systems trajectory tracking, such as space robots and manipulators with structural flexibility, has become a major field of interest due to the complexity and high computational load of these systems. Hierarchical sliding mode control has been investigated recently for these systems; however, the instability phenomena will possibly occur, especia...

The objective of this investigation is to evaluate the cyclic plastic deformation response at subsurface during rolling contact fatigue (RCF) under conditions pure and rolling-sliding. finite element simulation results indicate that slip-to-roll ratio (SRR)has an immense effect on evolution RCF. At SRR 0% (pure rolling), symmetric shear stress cycling evident subsurface, as a result shakedown t...

Sliding-mode observers are known to be robust against presence of disturbances and modeling uncertainties [1−3]. Although these observers are highly robust with respect to noises in system inputs, it turned out that the corresponding stability degrades in systems that exhibit output noise or mixed uncertainties [4]. When the measurements are noisy, because the time derivatives cannot be accurat...

We study the stability of steady sliding between elastically deformable continua using rate and state dependent friction laws. That is done for both elastically identical and elastically dissimilar solids. The focus is on linearized response to perturbations of steady state sliding, and on studying how the positive direct effect (instantaneous increase or decrease of shear strength in response ...

This paper addresses the problems caused by an inappropriate selection of sliding surface parameters in fuzzy sliding mode controllers via an optimization approach. In particular, the proposed method employs the parallel distributed compensator scheme to design the state feedback based control law. The controller gains are determined in offline mode via a linear quadratic regular. The particle ...

In this paper we investigate the tribological properties of AlSn-based alloy with different amount of graphite at different normal loads and sliding speed. A modified impeller mixing coupled with chill casting technique was used for the preparation of immiscible alloys. In this paper Al-Sn binary alloys was chosen for this study. This binary system shows the miscibility gap at different concent...

Sea ice contains flaws including frictional contacts. We aim to describe quantitatively the mechanics of those contacts, providing local physics for geophysical models. With a focus on the internal friction of ice, we review standard micro-mechanical models of friction. The solid’s deformation under normal load may be ductile or elastic. The shear failure of the contact may be by ductile flow, ...

BACKGROUND Friction between archwires and brackets is assuming greater importance for finishing with increased use of sliding mechanics in orthodontics as friction impedes the desired tooth movement. The following study is conducted to compare and evaluate the effect of ligation on friction in sliding mechanics using 0.022" slot bracket in dry condition. MATERIALS & METHODS In the study 48 co...

Tailored gradation in elastic–plastic properties is known to offer avenues for suppressing surface damage during normal indentation and sliding contact. In tribological applications, sliding contact analysis provides a more representative mechanism for fundamental understanding and design as it offers a tool to test materials under conditions of controlled abrasive wear. However, no such study ...

Interaction between a structure under base excitation and heavy non-structural elements that it supports is significant in the seismic analysis and design of the structure. Heavy non-structural elements may slide/rock under base excitation, and this dynamic action affects the seismic behavior of the supporting structure. Hence, in this study, a numerical model was presented to describe the seis...