scholarly journals Prognosis of a Degradable Hydraulic System

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Imad El Adraoui ◽  
Hassan Gziri ◽  
Ahmed Mousrij
Keyword(s):  
Hydraulic System ◽  
Computing Time ◽  
Performance Parameters ◽  
Critical System ◽  
Minimum Error ◽  
Multilayer Perception ◽  
Satisfactory Performance ◽  
Jump Model ◽  
Production Area

This article proposes a preliminary diagnostic/prognostic method for the identification of a critical system, undergoing a continuous evolutionary degradation, in a production area, and the determination of the component responsible for its degradation, called the failing element. Using for this, a model based on learning  by multilayer perception (MLP). The purpose of this paper is to provide a modeling approach that makes it possible to determine the level of degradation reached by the system at any given point of time, in a precise way. Thus, the horizon of the failure will be produced with a minimum error compared to the discrete jump model used in the literature. The proposed approach consists of using a neural network with fewer layers and optimal computing time. We performed data learning (tests) in order to illustrate a regression of good correlation of these data (tests) on a centrifugal pump with satisfactory performance parameters and compared it with other commonly used methods.

Automatic 3-D Crack Propagation Calculations in Industrial Components: A Pure Hexahedral versus a Combined Hexahedral-Tetrahedral Approach

2007 ◽  
Vol 348-349 ◽  
pp. 45-48
Author(s):  
Guido Dhondt
Keyword(s):  
Crack Propagation ◽  
Computing Time ◽  
Propagation Direction ◽  
Hexahedral Elements ◽  
Crack Propagation Direction ◽  
Low Weight ◽  
Out Of Plane ◽  
Hexahedral Meshes ◽  
Crack Faces

In recent years, increased loading and low weight requirements have led to the need for automatic crack tracing software. At MTU a purely hexahedral code has been developed in the nineties for Mode-I applications. It has been used extensively for all kinds of components and has proven to be very flexible and reliable. Nevertheless, in transition regions between complex components curved cracks have been observed, necessitating the development of mixed-mode software. Due to the curvature of the crack faces, purely hexahedral meshes are not feasible, and therefore a mixture of hexahedral elements at the crack tip, combined with tetrahedral in the remaining structure has been selected. The intention of the present paper is to compare both methods and to point out the strength and weaknesses of each regarding accuracy, complexity, flexibility and computing time. Furthermore, difficulties arising from the out-of-plane growth of the crack such as the determination of the crack propagation direction are discussed.

scholarly journals Experimental and Theoretical Study on Three Combustion Models for the Determination of the Performance Parameters of Nitrocellulose - Based Propellants

2020 ◽  
Vol 71 (9) ◽  
pp. 87-97
Author(s):  
Titi Paraschiv ◽  
Tudor Viorel Tiganescu ◽  
George Ovidiu Iorga ◽  
Raluca Elena Ginghina ◽  
Octavian Constantin Grigoroiu
Keyword(s):  
Chemical Composition ◽  
Energetic Materials ◽  
Specific Volume ◽  
Flame Temperature ◽  
Performance Parameters ◽  
Heat Of Explosion ◽  
Combustion Gases ◽  
Combustion Models ◽  
Double Base

Nitrocellulose based propellants are the main materials used for ballistic and rocket applications. The chemical composition of the propellants, the loading density and propellant grain geometry are the decisive parameters that influence the performance parameters in ballistic application. In this paper the authors evaluate three models of combustion for energetic materials for the determination of heat of explosion and specific volume together with the adiabatic flame temperature. The authors select six types of propellant (two simple base propellants, two double base propellants based on nitroglycerine and two triple base propellants based on nitroguanidine) and the authors determined the heat of explosion and specific volume using a bomb calorimeter and a Julius-Peters device. The results obtained from the combustion models were compared to the experimental results and assumptions were done on the influence of pressure and temperature on the chemical composition of combustion gases produced by the confined deflagration of nitrocellulose-based propellants.

Computing Schemes for Longitudinal Train Dynamics: Sequential, Parallel and Hybrid

2015 ◽  
Vol 10 (6) ◽  
Author(s):  
Qing Wu ◽  
Colin Cole
Keyword(s):  
Parallel Computing ◽  
Personal Computer ◽  
Computational Efficiency ◽  
Computing Time ◽  
The Other ◽  
Hybrid Scheme ◽  
Sequential Scheme ◽  
Parallel Scheme ◽  
Train Dynamics

Conventionally, force elements in longitudinal train dynamics (LTD) are determined sequentially. Actually, all these force elements are independent from each other, i.e., determination of each one does not require inputs from others. This independent feature makes LTD feasible for parallel computing. A parallel scheme has been proposed and compared with the conventional sequential scheme in regard to computational efficiency. The parallel scheme is tested as not suitable for LTD; computing time of the parallel scheme is about 165% of the sequential scheme on a four-CPU personal computer (PC). A modified parallel scheme named the hybrid scheme was then proposed. The computing time of the hybrid scheme is only 70% of the sequential scheme. The other advantage of the hybrid scheme is that only two processors are required, which means the hybrid scheme can be implemented on PCs.

Failure Diagnosis of Hydraulic Motor in Amphibious Assault Vehicles Based on Support Vector Machine (SVM)

2012 ◽  
Vol 503-504 ◽  
pp. 1545-1549
Author(s):  
Liang Hai Yi ◽  
Yu Cai Dong ◽  
Zi Wei Qi ◽  
Xiao Yan Wang ◽  
Ge Hua Fan ◽  
...  
Keyword(s):  
Hydraulic System ◽  
Occurrence Rate ◽  
Support Vector ◽  
Maximum Relative Error ◽  
Hydraulic Motor ◽  
Support Vector Regression Model ◽  
Limit Value ◽  
Renewal Period ◽  
Rate Of Failure

Hydraulic motor is one of the elements with a high occurrence rate of failure in hydraulic system of amphibious assault vehicles. When the motor leakage reaches the limit value allowed, the motor should be renewed or overhauled. Through an analysis of the influencing factors that affect hydraulic motor leakage of amphibious assault vehicles, this article establishes a support vector regression model for motor leakage and gets a maximum relative error of 4.29% between the fitted value and the measured value of motor leakage, which offers more reliable evidence for scientific determination of renewal period or overhaul period of hydraulic motor

DWT-PLS Regression on Near-Infrared Spectra for Moisture and Volatile Determination of Coal

2013 ◽  
Vol 848 ◽  
pp. 313-316
Author(s):  
Xiao Li Yang ◽  
Fan Wang ◽  
Ji Shu Chen ◽  
Gong Zhe Ma
Keyword(s):  
Partial Least Squares Regression ◽  
Bituminous Coal ◽  
Near Infrared ◽  
Parameters Optimization ◽  
Discrete Wavelet ◽  
Pls Regression ◽  
Least Squares Regression ◽  
Satisfactory Performance ◽  
Near Infrared Spectra

We studied moisture and volatile determination in bituminous coal samples using near-infrared (NIR) spectra. This research was developted by applying partial least squares regression (PLS) and discrete wavelet transform (DWT). Firstly, NIR spectra were pre-processed by DWT for fitting and compression. Then, DWT coefficients were used to build regression model with PLS. We used NIR spectra to determination moisture and volatile determination in coal samples seperately and simultaneously. Through parameters optimization, the results show that DWT-PLS can obtain satisfactory performance for separate and simultanous determination.

scholarly journals Hybrid Control Accommodation forWater-asset Management of Hydraulic Systems Subjected to Large Operating Conditions

2007 ◽  
Vol 2 (3) ◽  
pp. 241
Author(s):  
Eric Duviella ◽  
Pascale Chiron ◽  
Philippe Charbonnaud
Keyword(s):  
Asset Management ◽  
Hydraulic System ◽  
Hybrid Control ◽  
Operating Conditions ◽  
Hydraulic Systems ◽  
Selection Technique ◽  
Operating Modes ◽  
Transfer Delay ◽  
Simulation Results

The Hybrid Control Accommodation (HCA) strategy was proposed to improve the water-asset management of hydraulic systems by resource allocation and setpoint assignment. Hydraulic system dynamics are taken into account during the setpoint assignment step which consists in controlling gates for large operating conditions. For hydraulic systems subjected to strong disturbances, transfer delays are variable, thus different operating modes must be considered. A multimodelling method, associated to a selection technique of transfer delay, allowing for the determination of the number of models, is proposed. The simulation results on the first reach of the Neste canal show the effectiveness of the HCA strategy.

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