Mecanique & Industries最新文献_第6页

Analyse des conditions de rupture des canalisations des réseaux maillés due au phénomène de coup de bélier 分析由于锤击现象造成的网状网络管道破裂情况

Mecanique & Industries Pub Date : 2011-01-01 DOI: 10.1051/MECA/2011015

J. Gargouri, Ezzeddine Hadj-ta¨ıeb, C. Schmitt, G. Pluvinage

{"title":"Analyse des conditions de rupture des canalisations des réseaux maillés due au phénomène de coup de bélier","authors":"J. Gargouri, Ezzeddine Hadj-ta¨ıeb, C. Schmitt, G. Pluvinage","doi":"10.1051/MECA/2011015","DOIUrl":"https://doi.org/10.1051/MECA/2011015","url":null,"abstract":"Un modele numerique, permettant d’obtenir de maniere automatique des informations sur la propagation des ondes de coup de belier dans les reseaux mailles de conduites, est presente. Le modele tient compte des bifurcations et des derivations dans les reseaux de conduites ainsi que des pertes de charges. Il est constitue d’un systeme de deux equations aux derivees partielles non-lineaires de type hyperbolique resolu par la methode des caracteristiques. L’algorithme numerique ainsi construit fournit une estimation des pressions maximales dans le fluide et des contraintes maximales dans les parois dues a la fermeture rapide de vannes. Dans certains cas, la contrainte maximale peut devenir superieure a la contrainte admissible et provoque la rupture des conduites. La dangerosite d’un defaut de type cratere de corrosion a ete analysee en determinant la distribution des contraintes en tete de ce defaut. Les resultats obtenus permettent de calculer le facteur d’intensite de contraintes d’entaille applique. Cette grandeur est inseree dans un diagramme Integrite-Rupture de type SINTAP et les nœuds en situation critique sont determines. Il y a risque de rupture si le facteur de securite est inferieur a 2. Les resultats de calcul montrent que presque tous les nœuds du reseau analyse sont situes en dehors du domaine d’integrite.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"12 1","pages":"131-137"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87451623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Effect of thermal convection on frequency response of a perturbed vaporizing pastille-shaped droplet 热对流对扰动汽化颗粒状液滴频率响应的影响

Mecanique & Industries Pub Date : 2011-01-01 DOI: 10.1051/MECA/2011102

Kwassi Anani, R. Prud’homme, S. d’Almeida, K. Assiamoua

{"title":"Effect of thermal convection on frequency response of a perturbed vaporizing pastille-shaped droplet","authors":"Kwassi Anani, R. Prud’homme, S. d’Almeida, K. Assiamoua","doi":"10.1051/MECA/2011102","DOIUrl":"https://doi.org/10.1051/MECA/2011102","url":null,"abstract":"We study the dynamic response to small acoustic oscillations of a vaporizing droplet in shape of a pastille (a small liquid cylinder, called “pastille” in the sequel, the height of which being smaller than the radius of the base). Contrary to some previously proposed models, where the thermal convection effect inside the droplet is often neglected, the continuously fed pastille-shaped model takes into account the effects of both thermal convection and conduction. Curves related to different heat exchange coefficients are presented for the frequency response of the vaporization rate. The case where the feeding process at the bottom of the pastille is assumed isothermal (isothermal bottom regime) is compared to the one where the feeding process at the bottom of the pastille is adiabatic (adiabatic bottom regime). The response factor curves for the pure conduction model of the spherical droplet and for the present model of the “equivalent pastille” are also compared. The temperature field perturbation is then examined. As well as for the evaporation mass flow rate perturbation, comparisons are made between the regime with an isothermal bottom and the one with an adiabatic bottom. We find that, in spite of some divergences observed between the various cases, the frequency response of a droplet submitted to acoustic oscillations presents also some common points. It is shown that the life time (or residence time), the thermal diffusion time, and the period of the harmonic perturbation do intervene strongly in the behaviour of the vaporizing pastille. The liquid propulsion is a possible application of this basic study conducted as part of a thesis.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"39 1","pages":"301-313"},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87533580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Enhancement of flow boiling heat transfer in microchannels by nano- and micro-surface treatments 纳米和微表面处理增强微通道内流动沸腾换热

Mecanique & Industries Pub Date : 2011-01-01 DOI: 10.1051/MECA/2011111

H. Phan, N. Caney, P. Marty, S. Colasson, J. Gavillet

引用次数: 5

Simulation et analyse d’une structure non-linéaire à symétrie cyclique 非线性循环对称结构的仿真与分析

Mecanique & Industries Pub Date : 2010-11-01 DOI: 10.1051/MECA/2010047

Aurelien Grolet, F. Thouverez, Pierrick Jean

引用次数: 2

Modelling crowd-structure interaction 群体-结构互动建模

Mecanique & Industries Pub Date : 2010-11-01 DOI: 10.1051/MECA/2010057

P. Pécol, S. Pont, S. Erlicher, P. Argoul

引用次数: 14

Cable tension estimation by means of vibration response and moving mass technique 用振动响应和动质量法估算索张力

Mecanique & Industries Pub Date : 2010-11-01 DOI: 10.1051/MECA/2010058

A. Bellino, S. Marchesiello, A. Fasana, L. Garibaldi

{"title":"Cable tension estimation by means of vibration response and moving mass technique","authors":"A. Bellino, S. Marchesiello, A. Fasana, L. Garibaldi","doi":"10.1051/MECA/2010058","DOIUrl":"https://doi.org/10.1051/MECA/2010058","url":null,"abstract":"This paper approaches a novel technique to estimate cable tension simply based on its vibration response. The vibration response has been quite extensively adopted in the past due to its simplicity and, mainly, because the inverse approach allows the tension estimation with the cable in its original site. A first tentative approach consists in using a certain number of experimentally measured natural frequencies to be introduced in the theoretical vibration formula; this formula, however, involves also the cable length, the cable mass per unit length and its flexural rigidity. Unfortunately, some problems arise in its application to real structures, such as the case of suspended and cable-stayed bridges, because the exact cable length cannot be measured (it appears at the fourth exponent in the vibration formula); moreover section and weight can be estimated within a certain degree of accuracy, whilst the boundary conditions are often defined with difficulty. A novel extension of the method is here proposed, which takes advantage from a moving mass travelling on the cable. This is the case occurring when cables are verified with magnetic-based technology to detect rope faults and cross section reduction. In this way, the extracted natural frequencies are varying with time due to the moving load, and hence they have to be extracted adopting a time-varying approach. Although some approximation linked to the shape modification must be introduced, a simple iterative procedure can be settled, by considering the cable length as an unknown. An estimation of the equivalent length is given, and successively this value is used to obtain an estimation of the cable tension.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"24 1","pages":"505-512"},"PeriodicalIF":0.0,"publicationDate":"2010-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84670734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Prédiction du comportement dynamique du système de forage grande vitesse vibratoire 预测高速振动钻井系统的动态行为

Mecanique & Industries Pub Date : 2010-11-01 DOI: 10.1051/MECA/2010042

F. Forestier, Vincent Gagnol, P. Ray, Henry Paris

{"title":"Prédiction du comportement dynamique du système de forage grande vitesse vibratoire","authors":"F. Forestier, Vincent Gagnol, P. Ray, Henry Paris","doi":"10.1051/MECA/2010042","DOIUrl":"https://doi.org/10.1051/MECA/2010042","url":null,"abstract":"Le Forage Grande Vitesse Vibratoire (FGVV) est un nouveau procede de percage qui permet de tripler la productivite des percages profonds en supprimant les cycles d’evacuation des copeaux ainsi que la lubrification. Pour cela un porte-outil specifique aete developpe, qui entre en vibrations axiales auto-entretenues lors de la coupe et permet le fractionnement du copeau, facilitant ainsi sonevacuation. Pour anticiper uneeventuelle diminution de la duree de vie des roulements a billes de l’electrobroche resultant de ces vibrations, un modele global du comportement dynamique du systeme tete vibratoire-electrobroche est presente. Ce modele est base sur la modelisation du comportement des entites structurales par deselements-finis de type « poutre-rotor» prenant en compte les effets dynamiques associes aux hautes frequences de rotations de l’electrobroche, couple a des modeles d’interfaces identifies par la methode de couplage de receptance. Le modele est valide a l’aide d’experimentations qui montrent une bonne correspondance entre les resultats experimentaux et numeriques. Le modele est ensuite utilise pour calculer la duree de vie des roulements a billes de l’electrobroche lors de differentes operations de percage. L’influence de la frequence de rotation et de l’avance sur la duree de vie des roulements estetudiee, permettant ainsi de faire ressortir des plages de fonctionnement optimal.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"26 1","pages":"465-475"},"PeriodicalIF":0.0,"publicationDate":"2010-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86188572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental investigation of air bearings dynamic coefficients 空气轴承动力系数的实验研究

Mecanique & Industries Pub Date : 2010-11-01 DOI: 10.1051/MECA/2010043

P. Matta, L. Rudloff, M. Arghir

{"title":"Experimental investigation of air bearings dynamic coefficients","authors":"P. Matta, L. Rudloff, M. Arghir","doi":"10.1051/MECA/2010043","DOIUrl":"https://doi.org/10.1051/MECA/2010043","url":null,"abstract":"The paper presents the experimental work developed by the authors for the identification of rotordynamic coefficients of air bearings. Air bearings work at very high rotation speeds and are known to have nonlinear dynamic characteristics depending at least on the excitation frequency. The paper presents two very similar test rigs, the testing procedure and the algorithm for identifying the rotordynamic coefficients. The test rigs consist of a rigid rotor guided by fixed bearings and driven by a spindle. The dynamic loads are applied by two orthogonally mounted shakers applying two linear independent excitations. Two air bearings are analysed in the present paper. The test procedure is first developed for a simple circular bearing with easily predictable dynamic characteristics. Its rotordynamic coefficients are identified by using a least square procedure based on rational functions. The coefficients are compared to theoretical results in order to underline the limits of the identification algorithm. The procedure is next applied to a first generation foil bearing. Rotordynamic coefficients are presented for different working conditions (static loads and rotation speeds) and are discussed comparing them to circular air bearings.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"18 1","pages":"477-488"},"PeriodicalIF":0.0,"publicationDate":"2010-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82696206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Nonlinear phenomena in nanomechanical resonators: mechanical behaviors and physical limitations 纳米机械谐振器中的非线性现象:力学行为和物理限制

Mecanique & Industries Pub Date : 2010-11-01 DOI: 10.1051/MECA/2010068

N. Kacem, S. Baguet, S. Hentz, R. Dufour

引用次数: 27

SICODYN international benchmark on dynamic analysis of structure assemblies: variability and numerical-experimental correlation on an industrial pump SICODYN结构组件动态分析国际基准:工业泵的变异性和数值-实验相关性

Mecanique & Industries Pub Date : 2010-11-01 DOI: 10.1051/MECA/2010063

S. Audebert

{"title":"SICODYN international benchmark on dynamic analysis of structure assemblies: variability and numerical-experimental correlation on an industrial pump","authors":"S. Audebert","doi":"10.1051/MECA/2010063","DOIUrl":"https://doi.org/10.1051/MECA/2010063","url":null,"abstract":"A benchmark is organised to quantify the variability relative to structure dynamics computations. The chosen demonstrator is a pump in service in thermal central units, which is an engineered system with not well-known parameters, considered in its work environment. The blind modal characterisation of the separate pump components shows a 5%-12% variability on eigenfrequency values and a less than 15% frequency error in comparison with experimental values. The numerical-experimental MAC numbers reach 0.7 at the maximum, even after updating. An example of modal results on the pump assembly fixed is presented, which shows a larger discrepancy with measurement values, essentially due to the modelling of the interfaces and boundary condition, and to the possible simplification of the main components F.E. models to reduce their size. Though a significant frequency error, the first overall modes are correctly identified. If this tendency can be confirmed from all the participants' results, the conclusion to be drawn is that, if the predictive capability of F.E. models to represent the dynamical behaviour of sub-structures is satisfactory, the one relative to structures that are built-up of several components does not allow their confident use. Additional information issued from measurements is needed to improve their accuracy.","PeriodicalId":49847,"journal":{"name":"Mecanique & Industries","volume":"44 1","pages":"439-451"},"PeriodicalIF":0.0,"publicationDate":"2010-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78557676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15