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Vibrations characterization in milling of low stiffness parts with a rubber-based vacuum fixture

Chinese Journal of Aeronautics 2021年第6期34卷 54-66页

作者： Antonio RUBIO-MATEOS Mikel CASUSO Asuncion rivero Eneko UKAR Aitzol LAMIKIZ TECNALIA Basque Research and Technology Alliance(BRTA)Paseo Mikeletegi 7Pcirque TecnologicoE-20009 San SebastianSpain University of the Basque Country(UPV/EHU) ETTSII–Department of Mechanical EngineeringC/Alameda de Urquijo s/nE-48013 BilbaoSpain

Fixtures are a critical element in machining operations as they are the interface between the part and the *** components are responsible for the precise part location on the machine table and for the proper dynamic stability maintenance during the manufacturing *** these two features are deeply related,they are usually studied *** the one hand,diverse adaptable solutions have been developed for the clamping of different variable ***,the stability of the part has been long studied to reduce the forced vibration and the chatter effects,especially on thin parts machining operations typically performed in the aeronautic field,such as the skin panels *** present work proposes a commitment between both features by the presentation of an innovative vacuum fixture based on the use of a vulcanized rubber *** solution presents high flexibility as it can be adapted to different geometries while providing a proper damping capacity due to the viscoelastic and elastoplastic behaviour of these ***,the sealing properties of these elastomers provide the perfect combination to transform a rubber layer into a flexible vacuum ***,in order to validate the suitability of this fixture,a test bench is manufactured and tested under uniaxial compression loads and under real finish milling conditions over AA2024 part ***,a roughness model is proposed and analysed in order to characterize the part vibration sources.

关键词： AA2024 aeronautic skin Chatter Damping Finish milling Rubber characterization Vacuum clamping

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Modern data sources and techniques for analysis and forecast of road accidents:A review

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Journal of Traffic and Transportation Engineering(English Edition) 2020年第4期7卷 432-446页

作者： Camilo gutierrez-Osorio Cesar Pedraza Departamento de Ingeniena de Sistemas e Industrial Universidad Nacional de ColombiaBogotaColombia

Road accidents are one of the most relevant causes of injuries and death worldwide,and therefore,they constitute a significant field of research on the use of advanced algorithms and techniques to analyze and predict traffic accidents and determine the most relevant elements that contribute to road *** research of road accident prediction aims to respond to the challenge of offer tools to generate a more secure mobility environment,and ultimately,save *** paper aims to provide an overview of the state of the art in the prediction of road accidents through machine learning algorithms and advanced techniques for analyzing information,such as convolutional neural networks and long short-term memory networks,among other deep learning ***,in this article,a compendium and study of the most used data sources for the road accident forecast is *** a classification is proposed according to its origin and characteristics,such as open data,measurement technologies,onboard equipment and social media *** the analysis of the information,the different algorithms employed to make predictions about road accidents are listed and compared,as well as their applicability depending on the types of data being analyzed,along with the results obtained and their ease of interpretation and *** best results reported by the authors are obtained when two or more analytic techniques are combined,in such a way that analysis of the obtained results is *** the future challenges in road traffic forecasting lies the enhancement of the scope of the proposed models and predictions by the incorporation of heterogeneous data sources,that include geo spatial data,information from traffic volume,traffic statistics,video,sound,text and sentiment from social media,that many authors concur that can improve the precision and accuracy of the analysis and predictions.

关键词： Traffic engineering Data analysis Machine learning Road accident forecasting Traffic accident prediction

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Imprinting in plants

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Chinese Science Bulletin 2009年第14期54卷 2383-2389页

作者： gutierrez-MARCOS Jose Warwick HRI University of WarwickWellesbourneCV35 9EF UK

Genomic imprinting leads to the differential expression of parental alleles after fertilization. Imprinting appears to have evolved independently in mammals and flowering plants to regulate the development of nutrient-transfer placental tissues. In addition, the regulation of imprinting in both mammals and flowering plants involves changes in DNA methylation and histone methylation, thus suggesting that the epigenetic signals that regulate imprinting have been co-opted in these distantly related species.

关键词：开花植物 DNA甲基化基因组印记哺乳类动物差异表达基因胎盘组织养分转移信号调节

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An Andean tectonic cycle:From crustal thickening to extension in a thin crust(34°-37°SL)

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Geoscience Frontiers 2014年第3期5卷 351-367页

作者： Victor A.Ramos vanesa D.Litvak Andrés Folguera Mauro Spagnuolo Laboratorio de Tectonica Andina del Instituto de Estudios Andinos Don Pablo GroeberCONICET-Universidad de Buenos AiresArgentina

Several orogenic cycles of mountain building and subsequent collapse associated with periods of shal- lowing and steepening of subduction zones have been recognized in recent years in the Andes. Most of them are characterized by widespread crustal delamination expressed by large calderas and rhyolitic flare-up produced by the injection of hot asthenosphere in the subduction wedge. These processes are related to the increase of the subduction angle during trench roll-back. The Payenia paleoflat-slab, in the southern Central Andes of Argentina and Chile （34° -37°S） recorded a complete cycle from crustal thickening and mountain uplift to extensional collapse and normal faulting, which are related to changes in the subduction geometry. The early stages are associated with magmatic expansion and migration, subsequent deformation and broken foreland. New ages and geochemical data show the middle to late Miocene expansion and migration of arc volcanism towards the foreland region was associated with important deformation in the Andean foothills. However, the main difference of this orogenic cycle with the previously described cycles is that the steepening of the oceanic subducted slab is linked to basaltic flooding of large areas in the retroarc under an extensional setting. Crustal delamination is concentrated only in a narrow central belt along the cordilleran axis. The striking differences between the two types of cycles are interpreted to be related to the crustal thickness when steepening the subducting slab, The crustal thickness of the Altiplano is over 60-80 km, whereas Payenia is less than 42 km in the axial part, and near 30 km in the retroarc foothills. The final extensional regime associated with the slab steepening favors the basaltic flooding of more than 8400 km3 in an area larger than 40,000 km2, through 800 central vents and large fissures. These characteristics are unique in the entire present-day Andes.

关键词： Andes Retroarc magmatism Basaltic floods Crustal delamination Flat-slab

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Effect of surface loading on the hydro-mechanical response of a tunnel in saturated ground

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Underground Space 2016年第1期1卷 1-19页

作者： Simon Heru Prassetyo Marte gutierrez Department of Civil and Environmental Engineering Colorado School of MinesGoldenCO 80401USA

The design of underground spaces in urban areas must account not only for the current overburden load but also for future surface loads,such as from construction of high-rise buildings above underground *** saturated ground,the surface load will generate an additional mechanical response through stress changes and ground displacement,as well as a hydraulic response through pore pressure *** hydro-mechanical(H-M)changes can severely influence tunnel *** paper examines the effect of surface loading on the H-M response of a typical horseshoe-shaped tunnel in saturated *** tunnel models were created in the computer code Fast Lagrangian Analysis of Continua(FLAC).One model represented weak and low permeability ground(stiff clay),and the other represented strong and high permeability ground(weathered granite).Each of the models was run under two liner permeabilities:permeable and *** main cases were *** Case 1,the surface load was applied 10 years after tunnel *** Case 2,the surface load was applied after the steady state pore pressure condition was *** simulation results show that tunnels with impermeable liners experienced the most severe influence from the surface loading,with high pore pressures,large inward displacement around the tunnels,and high bending moments in the *** addition,the severity of the response increased toward steady *** induced H-M response was worse for tunnels in clay than for those in ***,the long-term liner stabilities in Case 1 and Case 2 were similar,indicating that the influence of the length of time between when the tunnel was completed and when the surface load was applied was *** findings suggest that under surface loading,in addition to the ground strength,tunnel stability in saturated ground is largely influenced by liner permeability and the long-term H-M response of the ground.

关键词： Surface loading Hydro-mechanical response Urban tunnels Saturated ground

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Axisymmetric alternating direction explicit scheme for efficient coupled simulation of hydro-mechanical interaction in geotechnical engineering-Application to circular footing and deep tunnel in saturated ground

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第2期10卷 259-279页

作者： Simon Heru Prassetyo Marte gutierrez Department of Civil and Environmental Engineering Colorado School of MinesGoldenUSA Mining Engineering Program Institut Teknologi BandungBandungIndonesia

Explicit solution techniques have been widely used in geotechnical engineering for simulating the coupled hydro-mechanical(H-M) interaction of fluid flow and deformation induced by structures built above and under saturated ground, i.e. circular footing and deep tunnel. However, the technique is only conditionally stable and requires small time steps, portending its inefficiency for simulating large-scale H-M problems. To improve its efficiency, the unconditionally stable alternating direction explicit(ADE)scheme could be used to solve the flow problem. The standard ADE scheme, however, is only moderately accurate and is restricted to uniform grids and plane strain flow conditions. This paper aims to remove these drawbacks by developing a novel high-order ADE scheme capable of solving flow problems in nonuniform grids and under axisymmetric conditions. The new scheme is derived by performing a fourthorder finite difference(FD) approximation to the spatial derivatives of the axisymmetric fluid-diffusion equation in a non-uniform grid configuration. The implicit Crank-Nicolson technique is then applied to the resulting approximation, and the subsequent equation is split into two alternating direction sweeps,giving rise to a new axisymmetric ADE scheme. The pore pressure solutions from the new scheme are then sequentially coupled with an existing geomechanical simulator in the computer code fast Lagrangian analysis of continua(FLAC). This coupling procedure is called the sequentially-explicit coupling technique based on the fourth-order axisymmetric ADE scheme or SEA-4-AXI. Application of SEA-4-AXI for solving axisymmetric consolidation of a circular footing and of advancing tunnel in deep saturated ground shows that SEA-4-AXI reduces computer runtime up to 42%-50% that of FLAC’s basic scheme without numerical instability. In addition, it produces high numerical accuracy of the H-M solutions with average percentage difference of only 0.5%-1.8%.

关键词： Hydro-mechanical(H-M) interaction Explicit coupling technique Alternating direction explicit(ADE) scheme High-order finite difference(FD) Non-uniform grid Axisymmetric consolidation Circular footing Deep tunnel in saturated ground

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UNCONDITIONAL CAUCHY SERIES AND UNIFORM CONVERGENCE ON MATRICES

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Chinese Annals of Mathematics,Series B 2004年第3期25卷 335-346页

作者： A.AIZPURU A.gutierrez-DAVILA DepartarnentodeMatematicas UniversidaddeCadizApdo.4011510-PuertoReal（Cadiz）Spain DepartamentodeMatematicas UniversidaddeCadizApdo.4011510-PuertoReal（Cadiz）Spain

The authors obtain new characterizations of unconditional Cauchy series in terms of separation properties of subfamilies of p(N), and a generalization of the Orlicz-Pettis Theorem is also obtained. New results on the uniform convergence on matrices and a new version of the Hahn-Schur summation theorem are proved. For matrices whose rows define unconditional Cauchy series, a better sufficient condition for the basic Matrix Theorem of Antosik and Swartz, new necessary conditions and a new proof of that theorem are given.

关键词： Unconditional Cauchy series Orlicz-Pettis theorem Summation Hahn-Schur theorem Basic matrix theorem

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Effectiveness of predicting tunneling-induced ground settlements using machine learning methods with small datasets

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第4期14卷 1028-1041页

作者： Linan Liu Wendy Zhou Marte gutierrez Department of Geology and Geological Engineering Colorado School of MinesGoldenCO80401USA Department of Civil and Environmental Engineering Colorado School of MinesGoldenCO80401USA

Prediction of tunneling-induced ground settlements is an essential task,particularly for tunneling in urban *** settlements should be limited within a tolerable threshold to avoid damages to aboveground *** learning(ML)methods are becoming popular in many fields,including tunneling and underground excavations,as a powerful learning and predicting ***,the available datasets collected from a tunneling project are usually small from the perspective of applying ML *** ML algorithms effectively predict tunneling-induced ground settlements when the available datasets are small?In this study,seven ML methods are utilized to predict tunneling-induced ground settlement using 14 contributing factors measured before or during tunnel *** methods include multiple linear regression(MLR),decision tree(DT),random forest(RF),gradient boosting(GB),support vector regression(SVR),back-propagation neural network(BPNN),and permutation importancebased BPNN(PI-BPNN)*** methods except BPNN and PI-BPNN are shallow-structure ML *** effectiveness of these seven ML approaches on small datasets is evaluated using model accuracy and *** model accuracy is measured by the coefficient of determination(R2)of training and testing datasets,and the stability of a learning algorithm indicates robust predictive ***,the quantile error(QE)criterion is introduced to assess model predictive performance considering underpredictions and *** study reveals that the RF algorithm outperforms all the other models with the highest model prediction accuracy(0.9)and stability(3.0210^(-27)).Deep-structure ML models do not perform well for small datasets with relatively low model accuracy(0.59)and stability(5.76).The PI-BPNN architecture is proposed and designed for small datasets,showing better performance than typical *** important contributing factors of ground settlements are identified,including

关键词： Ground settlements Tunneling Machine learning Small dataset Model accuracy Model stability Feature importance

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Physical model simulation of rock-support interaction for the tunnel in squeezing ground

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第1期14卷 82-92页

作者： Ketan Arora Marte gutierrez Ahmadreza Hedayat Civil and Environmental Engineering Colorado School of MinesGoldenCO80401USA

The existence of squeezing ground conditions can lead to significant challenges in designing an adequate support system for *** empirical,observational and analytical methods have been suggested over the years to design support systems in squeezing ground conditions,but all of them have some *** this study,a novel experimental setup having physical model for simulating the tunnel boring machine(TBM)excavation and support installation process in squeezing clay-rich rocks is *** observations are made to understand better the interaction between the support and the squeezing *** physical model included a large true-triaxial cell,a miniature TBM,laboratoryprepared synthetic test specimen with properties similar to natural mudstone,and an instrumented cylindrical aluminum support *** were conducted at realistic in situ stress levels to study the time-dependent three-dimensional tunnel support *** tunnel was excavated using the miniature TBM in the cubical rock specimen loaded in the true-triaxial cell,after which the support was *** confining stress was then increased in stages to values greater than the rock’s unconfined compressive strength.A model for the time-dependent longitudinal displacement profile(LDP)for the supported tunnel was proposed using the tunnel convergence measurements at different times and stress *** LDP formulation was then compared with the unsupported model to calculate the squeezing amount carried by the *** increase in thrust in the support was backcalculated from an analytical solution with the assumption of linear elastic *** on the test results and case studies,a recommendation to optimize the support requirement for tunnels in squeezing ground is proposed.

关键词： Squeezing ground Tunnel support system Longitudinal displacement profile Rock-support interaction

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Solving Delay Differential Equations through RBF Collocation

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Advances in Applied Mathematics and Mechanics 2009年第2期1卷 257-272页

作者： Francisco Bernal Gail gutierrez Institute for Scientific Computing Technical University of Dresden 01062 DresdenGermany Cir 1 No.73-34 Instituto de Energia y TermodinamicaUniversidad Pontificia BolivarianaMedellinColombia

A general and easy-to-code numerical method based on radial basis functions(RBFs)collocation is proposed for the solution of delay differential equations(DDEs).It relies on the interpolation properties of infinitely smooth RBFs,which allow for a large accuracy over a scattered and relatively small discretization ***’s multiquadric is chosen as RBF and combined with the Residual Subsampling Algorithm of Driscoll and Heryudono for support *** performance of the method is very satisfactory,as demonstrated over a cross-section of benchmark DDEs,and by comparison with existing general-purpose and specialized numerical schemes for DDEs.

关键词： Meshless method delay differential equations radial basis function multiquadric adaptive collocation

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