Search results for "mechanical"
showing 10 items of 5999 documents
Failure maps to assess bearing performances of glass composite laminates
2018
Aim of this article is the assessment of the bearing mechanical performances of pin-loaded glass laminates as function of their geometrical configuration. To this concern, 32 specimens having different hole diameter (D), laminate width (W), and hole center to laminate free edge distance (E) have been tested under bearing conditions. The maximum bearing stress and the stress-displacement curves were analyzed as function both of hole to laminate free edge distance E and hole diameter D. Moreover, an experimental 2D failure map was created by placing the experimental results (i.e., the kind of failure mechanism occurred for each geometrical configuration) in the plane E/D versus W/D ratios. In…
Multi-Component Fault Detection in Wind Turbine Pitch Systems Using Extended Park's Vector and Deep Autoencoder Feature Learning
2018
Pitch systems are among the wind turbine components with most frequent failures. This article presents a multicomponent fault detection for induction motors and planetary gearboxes of the electric pitch drives using only the three-phase motor line currents. A deep autoencoder is used to extract features from the extended Park's vector modulus of the motor three-phase currents and a support vector machine to classify faults. The methodology is validated in a laboratory setup of a scaled pitch drive, with four commonly occurring faults, namely, the motor stator turns fault, broken rotor bars fault, planetary gearbox bearing fault and planet gear faults, under varying load and speed conditions.
Teleoperation of industrial robot manipulators based on augmented reality
2020
[EN] This research develops a novel teleoperation for robot manipulators based on augmented reality. The proposed interface is equipped with full capabilities in order to replace the classical teach pendant of the robot for carrying out teleoperation tasks. The proposed interface is based on an augmented reality headset for projecting computer-generated graphics onto the real environment and a gamepad to interact with the computer-generated graphics and provide robot commands. In order to demonstrate the benefits of the proposed method, several usability tests were conducted using a 6R industrial robot manipulator in order to compare the proposed interface and the conventional teach pendant…
A Mathematical Model for Vehicle-Occupant Frontal Crash Using Genetic Algorithm
2016
In this paper, a mathematical model for vehicle-occupant frontal crash is developed. The developed model is represented as a double-spring-mass-damper system, whereby the front mass and the rear mass represent the vehicle chassis and the occupant, respectively. The springs and dampers in the model are nonlinear piecewise functions of displacements and velocities respectively. More specifically, a genetic algorithm (GA) approach is proposed for estimating the parameters of vehicle front structure and restraint system. Finally, it is shown that the obtained model can accurately reproduce the real crash test data taken from the National Highway Traffic Safety Administration (NHTSA). The maximu…
Geometrical deviation of end-of-life parts as a consequence of reshaping by single point incremental forming
2021
AbstractPutting in place circular economy strategies is an urgent challenge to face. In this scenario, manufacturing processes play a relevant role as efficient material reuse enabler. Scientists have to make an effort either to find new process or to rethink old process to reprocess end-of-life (EoL) component to recover both material and functions. In this paper, single point incremental forming (SPIF) process is used for reshaping sheet metal EoL components. The entire process chain was replicated including both deep drawing process (to imitate the end-of-life component) as well as SPIF operations (to obtain the reshaped components). The geometrical deviation as a consequence of SPIF ope…
Manufacturing processes as material and energy efficiency strategies enablers: The case of Single Point Incremental Forming to reshape end-of-life me…
2021
Abstract Making materials consumes about 21% of the global energy demand; concerning metals production, it accounts for about 8% of total global energy consumption. Circular economy strategies such as longer life, more intense use, repair, product upgrades, modularity, remanufacturing, component reuse, and open/closed-loop recycling are strategies to put in place urgently to reduce the environmental impact of raw material production. Although recycling of metals is the most used strategy and is being improved in terms of efficiency, it is mandatory moving towards more virtuous circular economy strategies, such as product/component reuse. In this paper a novel reuse strategy for sheet metal …
Prediction of Vehicle Crashworthiness Parameters Using Piecewise Lumped Parameters and Finite Element Models
2018
Estimating the vehicle crashworthiness parameters experimentally is expensive and time consuming. For these reasons different modelling approaches are utilized to predict the vehicle behaviour and reduce the need for full-scale crash testing. The earlier numerical methods used for vehicle crashworthiness analysis were based on the use of lumped parameters models (LPM), a combination of masses and nonlinear springs interconnected in various configurations. Nowadays, the explicit nonlinear finite element analysis (FEA) is probably the most widely recognized modelling technique. Although informative, finite element models (FEM) of vehicle crash are expensive both in terms of man-hours put into…
Cross-correlation of whitened vibration signals for low-speed bearing diagnostics
2019
Abstract Rolling-element bearings are crucial components in all rotating machinery, and their failure will initially degrade the machine performance, and later cause complete shutdown. The period between an initial crack and complete failure is short due to crack propagation. Therefore, early fault detection is important to avoid unexpected machine shutdown and to aid in maintenance scheduling. Bearing condition monitoring has been applied for several decades to detect incipient faults at an early stage. However, low-speed conditions pose a challenge for bearing fault diagnosis due to low fault impact energy. To reliably detect bearing faults at an early stage, a new method termed Whitened …
Re-forming end-of-life components through single point incremental forming
2020
Abstract Applying Circular Economy strategies is mandatory to face material demand while minimizing the environmental impact. Manufacturing processes are to be thought as means to enable material/component reuse strategies. This paper presents the suitability of Single Point Incremental Forming (SPIF) to re-form End-of-life sheet metal components. Deep drawing followed by SPIF process on aluminium alloys were carried out to simulate reforming processes chain. The resulting thinning and strain distributions were experimentally analysed for different configurations. The research proves that the local action and enhanced formability nature of SPIF allow non-homogeneously thinned and reduced fo…
Omnidirectional vision for UAV: applications to attitude, motion and altitude estimation for day and night conditions
2012
International audience; This paper presents the combined applications of omnidirectional vision featuring on its application to aerial robotics. Omnidirectional vision is first used to compute the attitude, altitude and motion not only in rural environment but also in the urban space. Secondly, a combination of omnidirectional and perspective cameras permits to estimate the altitude. Finally we present a stereo system consisting of an omnidirectional camera with a laser pattern projector enables to calculate the altitude and attitude during the improperly illuminated conditions to dark environments. We demonstrate that omnidirectional camera in conjunction with other sensors is suitable cho…