The importance of the gear loss factor in the power loss predictions was put in evidence comparing the predictions with experimental results.
It was concluded that the gear loss factor is a decisive factor to accurately predict the power loss.
Different formulations proposed in the literature were compared and it was shown that only few were able to yield satisfactory correlations with experimental results.
Temperature fields evolving during metal cutting processes have been of major interest. Temperatures in the tool influence the wear behaviour and hence costs, temperatures in the work-piece are directly responsible for later product quality. Due to the high significance of temperatures, many modelling attempts for temperature fields have been conducted, however failed to deliver satisfying results. The present paper describes an analytical model using complex functions based on potential theory.
This paper provides a comprehensive review of the literature regarding the modelling and control of piezoelectric inertial-friction actuators (PIFAs). A general architecture of PIFA is proposed first to facilitate the analysis and classification of the literature. In addition, the paper presents the future directions in modelling and control of PIFAs for further improvement of their performance.
Flying saw and cross cutter are techniques widely used to increase productivity but usually they are studied from a control point of view. This work highlights the kinematic and dynamic synthesis of a framework of a flying machine with the emphasis on the driving system chosen and the design parameter definition, in order to guarantee the required performance in terms of flexibility and high production volumes. The paper develops a flexibility oriented design to an horizontal wrapping machine.
Cold Spray is a novel technology for the application of coatings, in which bonding is realized by the acceleration of powder particles through a carrier gas and their high speed impact over a substrate material. Different nozzle designs are shown experimentally to vary in deposition efficiency, which cannot be explained by standard computational simulations. In order to amend the modelling techniques, a stronger coupling of solid and gas phase is employed, which provided improved results.
In this study, the drilling process was performed with Kirschner wire (K-wire) for stabilization after reduction of Salter–Harris type-3 epiphyseal fractures of distal femur. The numerical analyses were performed with finite element method. An analytic model and software were developed to identify the temperature distributions occurring in the K-wire and sawbones material during drilling process. A good consistency was obtained between experimental results and finite element analysis results.
In this research the motion planning problem for systems that admit a polynomial description of the system dynamics through differential flatness is tackled by parameterizing the system's so-called flat output as a piecewise polynomial. Sufficient conditions on the spline coefficients are derived ensuring satisfaction of the operating constraints over the entire time horizon and an intuitive relaxation is proposed to tackle conservatism.
The study addresses the significance of the coil geometry, number of turns, orientation, and mass flow on heat transfer performance. The outcome proves experimentally that such parameters have substantial impact on the rate of heat transfer as well as coil effectiveness. The study outcome is beneficial to wide technical sectors whose have interest in utilizing water pool as a coolant medium such as oil and gas companies, power plants, petrochemicals industries, and other firms.
Reverse fault movement is one of the threats for the structural integrity of buried oil-gas pipelines caused by earthquakes. Evaluation of the response of buried oil-gas pipelines crossing the faults can be used to safety evaluation, maintenance and seismic design. Buckling mode of non-pressure pipeline is collapse under reverse fault, while the buckling mode of pressure pipeline is wrinkle. A protective device was designed for preventing pipeline damage crossing fault area for its simple struct
In this study, the effect of fins’ height and Stefan number on performance of a shell and tube heat exchanger which contains a phase change material is investigated numerically and experimentally.Melting time, solidification time, liquid mass fraction, melting and solidification front and temperature distribution in different directions (longitudinal, radial and angular) are among criteria for the heat exchangers’ comparison.
The coupled dynamic model of the motor-driven flexible manipulator system (MDFMS) is proposed. It observes that the dynamic effect of the driving motor has a significant influence on the dynamic characteristic of the flexible manipulator, the Young's modulus of the flexible arm and the end effector have a considerable effect on the vibration responses, and larger velocities and accelerations have a suppressing effect on the influence of the driving motor.
The time optimal path following problem for industrial robots regards the problem of generating trajectories that follow predefined end-effector paths in shortest time possible, taking into account kinematic and dynamic constraints. This paper proposes an approach to deal with arbitrary long geometric paths. Further a method is presented to achieve suitable smooth trajectories for an implementation on a real robot, in an easy way.
The intervertebral disc is submitted to complex loading, which are responsible for variations of the hydrostatic pressure in its structure. The objective of the present work is to determine the internal pressure that promotes the porcine disc disruption. The tests were performed using a hydraulic cylinder that inflates the discs. It was concluded that potential for porcine disc injury may exist at low pressures for and the rupture could occur within intradiscal physiological pressures.