The present paper used the modal frequency method to diagnose fracture damage experimentally in simple structures, based on analytical theory of spring-loaded “fracture-hinge.” It is illustrated that geometry uniquely defines spring constant “fracture hinge,” which therefore independent loading strength, vibration, and location. experiment also measures change frequencies locate beam. With an accurate model for experimental samples, locations damages can be predicted within accuracy one...

This article applies high-order differential estimation to the motion planning of humanoid robots for first time. A multiobjective optimization model and corresponding optimal policy are designed from perspective solving time-varying linear equations. method can avoid calculation Jacobian matrix pseudo-inverse its derivative, reduce energy consumption, achieve smooth human-like robot motions. High-order is realized by cascading multiple integration-enhanced differentiators, which estimate...

This investigation studies a two-dimensional model of layered medium subjected to the frictional excitation high-speed asperity traversing over surface medium. The general analytical solutions mechanical stress state, temperature field and thermal state are obtained expressed in Fourier transform expressions. Numerical carried out for cases uniform parabolic pressure distributions. resulting yields conditions initiate cracks paper further thickness effect layer, relative stiffness layer...

When a manipulator works in dynamic environments, it may be affected by obstacles and cause danger to people around. This requires the able plan obstacle avoidance motion real time. Therefore, problem solved this paper is with whole body of redundant manipulator. The difficulty how model reflect relationship between obstacle. In order describe accurately occurrence conditions collision, we propose triangular collision plane, predictable based on geometric configuration Based model, three...

The present paper discussed the critical depth, i.e., depth at which thermal tensile stress reaches a maximum, caused by frictional excitation of fast moving asperity. In study, was computed directly maximizing with respect to positions under asperity inside material. relationship between and Peclet number for all materials in two-dimensional formulation may be simplified satisfy exponential form R(ηcr)2.275=20.4368. Stellite III chosen as indicator Other parametric effects including...

This investigation considers the thermo-mechanical effects of an asperity traversing at a high speed over semi-infinite medium with thin, hard coated surface. The general analytical solution temperature field and thermal stress state are obtained expressed in Fourier transform space. analysis emphasizes heating effect friction force, which leads to initiation cracking or “heat-checking,” coating layer, substrate, their interface. For layers, crack will occur either substrate interface...

The present paper explores the Airy stress function for a general class of elastic dislocation problems in doubly connected region. basic concept theory and theory, included, are essential to derivation method. Applications deal with two shapes cuts; an arbitrary straight cut logarithmic spiral cut. For simplicity illustrative purpose, only infinite region circular hole has been considered. discussion deals singular point uniqueness solution.

ABSTRACT The dynamic response of planar frame structures composed damped Bernoulli-Euler beams is computed, with and without a crack present in the structure. inertance changes due to are investigated relation location, aim developing diagnosis method. optimum excitation location frequency locations for measurement determined best results. effects severity damping investigated. Damping accounted by complex Young's modulus. Frames analyzed electrical analogy A modeled as torsional spring,...

Moire´ fringe equations are developed for directly determining the components of Green’s and Conchy’s deformation tensors from pitch angle measurements. The derived using method indicial representation specimen master grid geometries. may be arbitrarily changed during course an experiment to obtain more easily measurable patterns. results specifically verified measurement a large simple shear deformation.

This paper is concerned with the finite element technique for predicting dynamic properties of anisotropic fiber-reinforced composite laminated plates. Considering effect transverse shear deformation, a higher order deformation theory which satisifes zero stress conditions at upper and bottom surfaces assumed. The natural frequencies mode shapes rectangular plate all free edges are obtained by method modal damping values damped technique. An equivalent stiffness introduced to reduce...

The present paper investigates the random temperature response of a coated medium subjected to fast moving asperity, taking into consideration randomness coating thickness. While thickness is uniform for individual specimens, there small variation from one specimen another in statistical space. Stochastic responses solid media are investigated by perturbation method, and results presented terms mean value standard deviation field. numerical example considers typical stochastic process. It...

This paper discusses the temperature distribution and stress state in vicinity of a near-surface rectangular cavity. They occur when solid is subjected to Coulomb frictional loading an asperity moving at moderately high speed. The finite difference method employed calculate both fields. energy balance applied corners cavity resolve problem singularities field there. singularity each corner represented by special element that introduced representing behavior known its surrounding vicinity....

This paper deals with the problem of an asperity-excited thermo-mechanical field in a medium thin surface layer and near void defect. The solutions for temperature distribution stress state vicinity are obtained. Numerical results obtained using material properties Stellite III both coating substrate. parametric effects substrate considered by varying corresponding property or coated cavity compared single cavity. In case cavity, while thermal is much larger than no case, principal...

The mobile humanoid upper body robot combines the with platform. It has high redundancy and can complete complex tasks. However, coupling joints, including waist joints platform, exist in configuration of robot. During task execution, motion end-effectors on dual arms are not independent, but interfere each other through Therefore, we need to decouple platform from arms. Based pseudo-inverse method redundant manipulators, consider as a disturbance term propose kinematic decoupling whole-body...