Procedure for the preparation and defense of the research plan

Doctoral candidates must submit a research plan, which will be included in their doctoral student activity report, before the end of the first year. The plan may be improved over the course of the doctoral degree. It must be endorsed by the tutor and the supervisor, and it must include the method that is to be followed and the aims of the research.

At least one of these annual assessments will include a public presentation and defence of the research plan and work done before a committee composed of three doctoral degree holders, which will be conducted in the manner determined by each academic committee. The examination committee awards a Pass or Fail mark. A Pass mark is a prerequisite for continuing on the doctoral programme. Doctoral candidates awarded a Fail mark must submit a new research plan for assessment by the academic committee of the doctoral programme within six months.

The committee assesses the research plan every year, in addition to all of the other activities in the doctoral student activity report. Doctoral candidates who are awarded two consecutive Fail marks for the research plan will be obliged to definitely withdraw from the programme.

If they change the subject of their thesis, they must submit a new research plan.

Formation activities

Procedure for assignment of tutor and thesis director

The academic committee of the doctoral programme assigns a thesis supervisor to each doctoral candidate when they are admitted or enrol for the first time, taking account of the thesis supervision commitment referred to in the admission decision.

The thesis supervisor will ensure that training activities carried out by the doctoral candidate are coherent and suitable, and that the topic of the candidate’s doctoral thesis will have an impact and make a novel contribution to knowledge in the relevant field. The thesis supervisor will also guide the doctoral candidate in planning the thesis and, if necessary, tailoring it to any other projects or activities undertaken. The thesis supervisor will generally be a UPC professor or researcher who holds a doctoral degree and has documented research experience. This includes PhD-holding staff at associated schools (as determined by the Governing Council) and UPC-affiliated research institutes (in accordance with corresponding collaboration and affiliation agreements). When thesis supervisors are UPC staff members, they also act as the doctoral candidate’s tutor.

PhD holders who do not meet these criteria (as a result of their contractual relationship or the nature of the institution to which they are attached) must be approved by the UPC Doctoral School's Standing Committee in order to participate in a doctoral programme as researchers with documented research experience.

The academic committee of the doctoral programme may approve the appointment of a PhD-holding expert who is not a UPC staff member as a candidate’s thesis supervisor. In such cases, the prior authorisation of the UPC Doctoral School's Standing Committee is required. A UPC staff member who holds a doctoral degree and has documented research experience must also be proposed to act as a co-supervisor, or as the doctoral candidate’s tutor if one has not been assigned.

A thesis supervisor may step down from this role if there are justified reasons (recognised as valid by the committee) for doing so. If this occurs, the academic committee of the doctoral programme will assign the doctoral candidate a new thesis supervisor.

Provided there are justified reasons for doing so, and after hearing any relevant input from the doctoral candidate, the academic committee of the doctoral programme may assign a new thesis supervisor at any time during the period of doctoral study.

If there are academic reasons for doing so (an interdisciplinary topic, joint or international programmes, etc.) and the academic committee of the programme gives its approval, an additional thesis supervisor may be assigned. Supervisors and co-supervisors have the same responsibilities and academic recognition.

The maximum number of supervisors of a doctoral thesis is two: a supervisor and a co-supervisor.

For theses carried out under a cotutelle agreement or as part of an Industrial Doctorate, if necessary and if the agreement foresees it this maximum number of supervisors may not apply. This notwithstanding, the maximum number of supervisors belonging to the UPC is two.

More information at the PhD theses section

Permanence

The academic committee of the programme may authorise an extension of up to one year for full-time doctoral candidates who have not applied to deposit their thesis by the end of the three-year period of study, in the terms outlined in the Academic Regulations for Doctoral Studies of the Universitat Politècnica de Catalunya. In the case of part-time candidates, an extension of two years may be authorised. In both cases, in exceptional circumstances a further one-year extension may be granted by the Doctoral School's Standing Committee, upon the submission of a reasoned application by the academic committee of the doctoral programme.

A doctoral candidate may be dismissed from a doctoral programme for the following reasons:

• The doctoral candidate submitting a justified application to withdraw from the programme.
• The maximum period of study and of extensions thereof ending.
• The doctoral candidate not having enrolled every academic year (unless he or she has been authorised to temporarily withdraw).
• The doctoral candidate failing two consecutive assessments.
• The doctoral candidate having disciplinary proceedings filed against him or her that rule that he or she must be dismissed from the UPC.

Dismissal from the programme implies that doctoral candidates cannot continue studying at the UPC and the closing of their academic record. This notwithstanding, they may apply to the academic committee of the programme for readmission and the committee must reevaluate them in accordance with the criteria established in the regulations.

International Mention

The doctoral degree certificate may include International Doctorate mention. In this case, the doctoral candidate must meet the following requirements:

a) During the period of study leading to the award of the doctoral degree, the doctoral candidate must have spent at least three months at a respected higher education institution or research centre outside Spain to complete courses or do research work. The stays and activities carried out must be endorsed by the thesis supervisor and authorised by the academic committee of the programme. The candidate must provide a certifying document issued by the person responsible for the research group of the body or bodies where the stay or activity was completed. This information will be added to the doctoral student’s activity report.
b) Part of the thesis (at least the summary and conclusions) must be written and presented in one of the languages commonly used for science communication in the relevant field of knowledge, which must not be an official language of Spain. This rule does not apply to stays and reports in Spanish or to experts from Spanish-speaking countries.
c) At least two PhD-holding experts belonging to a higher education institution or research centre outside Spain must have issued officially certified reports on the thesis.
d) The thesis examination committee must have included at least one PhD-holding expert from a higher education or research institution outside Spain who was not responsible for the candidate’s stay abroad (point a) above).
e) The thesis defence must have taken place on UPC premises or, in the case of joint programmes, at the location specified in the collaboration agreement.

List of authorized thesis for defense

Last update: 04/10/2023 04:45:29.

List of lodged theses

• LOAIZA DUQUE, JULIÁN DAVID: Machine-Learning to Promote Better Practices of Low-Cost Wearable Devices in Tremor Diseases
  
  Author: LOAIZA DUQUE, JULIÁN DAVID
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Mechanical Engineering (EM)
  Mode: Normal
  Deposit date: 29/09/2023
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: SÁNCHEZ EGEA, ANTONIO JOSÉ | GONZALEZ ROJAS, HERNAN ALBERTO
  Committee:
       PRESIDENT: MARTÍNEZ VÁZQUEZ, PABLO
       SECRETARI: MONJO MUR, LLUÍS
       VOCAL: VALLDEORIOLA SERRA, FRANCESC
  Thesis abstract: The most common tremor disorders worldwide are Parkinson's Disease and Essential Tremor. The gold standard for diagnosing these movement disorders is medical evaluation by neurologists, but its accuracy depends on the expertise of the doctor. Although there are effective tests such as 123I-FP-CIT SPECT, they are costly and have limited accessibility in developing regions. Additionally, these tests can be invasive.Currently, no cost-effective and non-invasive methods exist to differentiate these disorders accurately. Some research has used inertial measurement units to record and classify tremors, but their clinical implementation is complicated. This study focuses on developing an affordable, non-invasive, and easy-to-use diagnostic support tool using wearable devices with inertial sensors and machine learning-based classification models to achieve real-time classification of these disorders.To achieve this, an initial kinematic analysis of hand tremor records was conducted using accelerometers and gyroscopes from smartphones and inertial measurement units. Discriminatory features of tremors in the frequency spectrum were extracted, and machine learning models were developed to distinguish between physiological and pathological tremors and between the two types of tremors of interest. The initial phase results were published in three articles, demonstrating the potential of this methodology.The tool was conceived as a modular system that includes a mobile application for data acquisition, a RESTful API for processing and classifying data, and a database for storing patient records. The mobile application was developed in Kotlin for Android devices, while the algorithms and models were implemented in Python along with the RESTful API. A PostgreSQL database was also implemented to store patient records with confirmed diagnoses. It will be used to continuously improve the accuracy of machine learning models to make them more robust. This project is called TremorSoft.This approach aims to provide a cost-effective and accurate solution to assist in differentiating tremor disorders, improving healthcare in resource-limited areas and offering a helpful tool for neurologists and specialized doctors.
  

Last update: 04/10/2023 04:30:30.

List of defended theses by year

• ADROVER MONSERRAT, BÀRBARA: Study of the characterization of the mechanical properties of materials with elastomeric behavior for biomedical applications
  
  Author: ADROVER MONSERRAT, BÀRBARA
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Mechanical Engineering (EM)
  Mode: Normal
  Reading date: 24/03/2023
  Thesis director: TRAVIESO RODRIGUEZ, JOSE ANTONIO | JEREZ MESA, RAMON
  

  Committee:
       PRESIDENT: BUJ CORRAL, IRENE
       SECRETARI: GÓMEZ GRAS, GIOVANNI
       VOCAL: LANDON, YANN
  Thesis abstract: The mechanical characterization of new materials used in the Material Extrusion technique (MEX) in 3D printing is essential. The use of this technique is growing and with it the possible applications of printed polymeric parts. Thermoplastic elastomers (TPE) are MEX processable materials because they have the typical properties of thermoplastics but also have the flexible properties typical of elastomers. As they are new materials in the world of MEX, there is a lack of knowledge about their behavior when they are extruded, and, therefore, their potential use for advanced applications, particularly in the biomedical industry.This dissertation presents a mechanical study of TPEs that have been processed through MEX. The materials have different polymer bases and Shore hardnesses: TPU 98A (polyurethane-based), PEBA 90 A (polyether amide-based), TPO 90A, and TPO 96A (both olefin-based). A thermo-analytical characterization was performed before the mechanical testing. The lack of specific standards addressing this characterization for TPE materials posed one of the main challenges of the work. It was composed of a thermo-gravimetric analysis (TGA) and a differential scanning calorimetry (DSC). Once the critical temperatures of each material were detected, a qualitative study of the inter- and intra-layer bonds of the four TPEs was carried out. From this study, the extrusion temperature, the printing speed, and the optimal layer height for each material were obtained.The mechanical study consisted of three types of tests. The first one was a tensile characterization. The specimens were manufactured according to the ASTM D638 standard and based on a full factorial design of experiments (DoE). In this test, the influences of two printing parameters (layer height and filling percentage) on the tensile responses (Young's modulus and yield strength) were studied with the help of an analysis of variance (ANOVA). The second test was a study of the viscoelastic properties of PEBA 90A. To complete that, filaments were printed by varying the temperature and printing speed to observe the possible effects of these parameters on viscoelasticity. Uniaxial tests were carried out where the relaxations and behavior of PEBA were evaluated in fast cycles. The results of the tests were introduced to a quasi-linear visco-elastic model (QLVE), to finally define and predict its viscoelastic properties. In third place, tensile tests were carried out. In this case, the samples were printed in three directions (X, Y, and Z). To quantify the strength of the different unions, Acoustic Emission sensors were used during the tests. Based on the hits or events obtained, the three types of specimens could be differentiated.The final part of the thesis consisted of a case study of printing organ models, carried out with the collaboration of a hospital. Organ models in the world of biomedicine allow costs to be minimized and resources to be optimized (which can be materials, the time needed, etc.). Therefore, introducing new materials that provide new textures is necessary. For the application, optimal parameters defined throughout the thesis were used.This thesis provides a validated methodology to analyze the mechanical properties of TPE materials processed through MEX. Its most important conclusion is that each material must be dealt with individually. It cannot be assumed that MEX processing is optimized with the same printing parameters for all flexible materials. This is why the characterization of new materials is essential. In addition to a proposed methodology that works for everyone, even if the results obtained depend on the polymer base or the Shore hardness.
  

• MENDIZÁBAL DINUCCI, VIRGINIA DOLORES: Anàlisi del comportament de bigues de formigó armat reforçades amb FRCM vegetal sota càrregues de flexió cíclica
  
  Author: MENDIZÁBAL DINUCCI, VIRGINIA DOLORES
  Thesis link: http://hdl.handle.net/10803/688984
  Programme: DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Strength of Materials and Structural Engineering (RMEE)
  Mode: Normal
  Reading date: 23/03/2023
  Thesis director: GIL ESPERT, LLUIS | BERNAT MASÓ, ERNEST
  

  Committee:
       PRESIDENT: DE LA FLOR LÓPEZ, SILVIA
       SECRETARI: PELA, LUCA
       VOCAL: PEREZ MARTINEZ, MARCO ANTONIO
  Thesis abstract: Fiber-Reinforced Cementitious Matrix (FRCM) is a strengthening method that has been increasing its importance versus Fiber-Reinforced Polymer (FRP) due the lower cost and lower toxicity of its materials. The 3-stage behavior makes FRCM an interesting option when structures are subjected to non-static loads.For this reason, researchers have been characterising this strengthening system and they have applied it to structures as masonry or reinforced concrete. Its good compatibility with the substrate has been providing good results over the years. Society has raised awareness in the importance of the environment and the impact the industry has in it, affecting every industry. In strengthening of structures, it provoked an interest on the substitution of the fibers used in FRP and FRCM from synthetic to natural ones that could bear the loads required.Fibers like flax, sisal or hemp provided good results when high loads are applied, and other fibers as cotton are interesting for its potential elongation.Being natural fibers applied to a fresh mortar matrix, they can be deteriorated due the elevated pH of the matrix, therefore a coating was needed. The most common ones are epoxy resin, polyester resin or vinyl, that not only protects the fiber, but also increases its mechanical properties.Nowadays, there is also research regarding the coatings applied to the strengthening systems, using tree¿s resins or beeswax.In this doctoral thesis, it is proposed the application of vegetal FRCM to reinforced concrete beams subjected to cyclic bending loads.First, the mechanical characterization of the hemp or cotton FRCM is performed in all the stages: uncoated/coated threads mechanical properties, compatibility between the coating and the matrix, mesh mechanical properties and finally FRCM mechanical properties.Two synthetic and two natural resins are used in the characterization to choose two for the big format experimental campaign. After seeing the bad compatibility between the natural resin and the matrix, it was decided to continue the research with the epoxy and polyester resin.The interaction between the strengthening system and the substrate is performed through adapting the normative that regulates the adherence between the reinforcing stell bars and the concrete, determining the failure mode according to the fibre.3m length reinforced concrete beams are used to perform the bending test. Before the testing a modal analysis is performed pre and post strengthening to see the impact of the strengthening system on the natural mode¿s frequencies of the beams. Increasing the first bending mode, but decreasing the first torsion one.Finally, the bending test is performed. A static one for the control beams and a cyclic one for the reinforced ones. In the cyclic, the displacement of the actuator was increased progressively. As highlights, the reinforced beams increase the maximum load they can bear and the cotton-FRCM strengthened beams absorb enough energy to avoid the traction armour failure and avoiding a total collapse of the structure.Also, a numerical model simulation is proposed to simulate the behaviour of strengthened beams under this type of loads. It has been calibrated using the control and epoxy-coated FRCM achieving good approximation. To validate it, the properties of the mesh were substituted with the polyester ones instead of the epoxy ones, but the accuracy achieved for epoxy ones were not achieved.
  

• MOHAMED YOUSIF ABDALLAH ELMANSY, REDA: Study of the flow around a square cylinder with an upstream splitter plate
  
  Author: MOHAMED YOUSIF ABDALLAH ELMANSY, REDA
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Fluid Mechanics (MF)
  Mode: Normal
  Reading date: 19/01/2023
  Thesis director: BERGADÀ GRANYÓ, JOSEP MARIA | MELLIBOVSKY ELSTEIN, FERNANDO PABLO
  

  Committee:
       PRESIDENT: MESEGUER SERRANO, ALVARO
       SECRETARI: PUJOL SAGARO, ANTONI
       VOCAL: HUERA HUARTE, FRANCISCO
  Thesis abstract: This PhD mostly focuses in studding the flow around a square cylinder with an upstream splitter plate and considering different velocity ratios between the upper and lower inlet velocities. The PhD is based in three main studies:1.-The flow instabilities, involving the transition from two dimensional to three dimensional flow, the Hopt, Neimark Sacker bifurcations as well as the road to chaos, all of them were determined as a function of the velocity ratio. A parametric study was also performed involving the instabilities performance as a function of the splitter plate length and the distance splitter plate square cylinder.2.-Two dimensional and full three dimensional CFD-DNS simulations were undertaken to find out the wake topology and aerodynamic performances such as, dynamic lift, drag, pressure and friction coefficients, Strouhal numbers, boundary layer dynamics as well as the different instability modes.3.- Wake past circular cylinder has been investigated to characterize the three-dimensional instability in the transitional regime when the boundary layer over the cylinder surface is laminar and shear layer separating the surface undergoes intermittently unstable displacements which manifests in the form of small time and length scale vortical structures. The wake in this flow regime is modestly turbulent and the streamwise velocity profiles across the flow stream feature typical U-shape profile.
  

• MONSHI TOUSI, NAVID: Active Flow Control Optimization on Selig Donovan 7003 Airfoil
  
  Author: MONSHI TOUSI, NAVID
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Fluid Mechanics (MF)
  Mode: Normal
  Reading date: 16/06/2023
  Thesis director: BERGADÀ GRANYÓ, JOSEP MARIA | MELLIBOVSKY ELSTEIN, FERNANDO PABLO
  

  Committee:
       PRESIDENT: BUGEDA CASTELLTORT, GABRIEL
       SECRETARI: PUJOL SAGARO, ANTONI
       VOCAL: HERRERO SABARTÉS, JUAN
  Thesis abstract: The PhD focuses on the study of the flow around an airfoil at different Angles of Attack (AoA) with and without the implementation of Active Flow Control (AFC), while maintaining the Reynolds number constant at 60,000. The advantages of employing AFC technology are clearly established.The PhD is divided into three main studies:1- The flow over the airfoil at different AoA and using the 2D Spalart-Allmaras (SA) RANS turbulence model is studied. A novel and precise methodology is employed to optimize five AFC-associated parameters.2- In the second stage, three-dimensional Large Eddy Simulations (LES) are conducted on both the baseline and the previously optimized actuated cases to examine the appropriateness of the SA turbulence model for the AFC optimization.3- The effect of AFC on the flow performance, boundary layer, separation, and the forces acting on the airfoil is explored as a function of the nutilda boundary conditions value at the computational domain inlet and the synthetic jet. The optimum values of nutilda, which generate the most precise 2D-RANS-SA simulations, are obtained.
  

• TORRENT GELMÀ, MIQUEL: Parametrització d'una Bomba d'Engranatges Externs i Validació en Condicions Reals
  
  Author: TORRENT GELMÀ, MIQUEL
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Fluid Mechanics (MF)
  Mode: Normal
  Reading date: 31/03/2023
  Thesis director: CODINA MACIA, ESTEBAN | GAMEZ MONTERO, PEDRO JAVIER
  

  Committee:
       PRESIDENT: VERNET PEÑA, ANTON
       SECRETARI: CASTILLA LOPEZ, ROBERTO
       VOCAL: GONZÁLEZ CASTRO, JOSEP RAMON
  Thesis abstract: Pumps of positive volumetric displacement (PDVP) drive a volume of fluid from suction to discharge for each revolution of its shaft, called derived capacity, and therefore, in an ideal constant capacity pump the flow rate is proportional to the rotation speed and independent of the working pressure. This characteristic makes them very suitable to be used in oleo-hydraulic energy transmission systems (STEO). In a non-ideal pump, the flow losses due to leaks and the torque losses due to friction must be considered, evaluated through ISO experimental tests. With these results can be made a parameterization of pump behaviour in a permanent regime (average flow and average torque depending on the operating conditions) as well as its pulsating behaviour (flow ripple superimposed on the average flow as an intrinsic consequence of the pumping mechanism). The first part of the Thesis has been dedicated to this experimental parameterization. There are no precedents for any verification if this parameterization carried out with laboratory data and the consequent modelling is sufficient to predict the behaviour of these hydrostatic units in real working conditions. This validation has been the main objective of the second part of the Thesis.As part of the BRITE "ECOPUMP" project, multiple external gear pumps (EGP) have been tested, and a reference pump of this type has been chosen to carry out the study. It is first of all to get to know in depth the operation of this type of pump, in order to have the necessary criterion to interpret the subsequent results. Next, all the experimental tests were carried out to perform the parameterization and modelling of its behaviour. Finally, experimental field tests have been carried out in real work cycles that allow the measured data to be compared with the results of the model under the same operating conditions.However, the EGP have a simple construction, the mechanism for compensating the axial clearance between the floating bushing plates and the gears is the key to their behaviour. Therefore, to interpret the discrepancies between the measured data in the field tests and the results of the simulation, it is essential to study the dynamics of these plates. A tool is needed that allows simultaneous monitoring this movement together with the behaviour of the pump, and therefore, a model of the plate dynamics that can be integrated into the pump model. The Bond Graph technique is very suitable for this purpose. A tool has been created that allows simulate in real time long work cycles with a conventional computer, without using complex CFD software. Emphasize the use of the analogy of analytical solutions of hydrodynamic bearings with lubrication in the studied domain. The dimensional analysis has led us to use expressions that, to be valid, must be adjusted with experimental results that relate the movement of the plates to the operating conditions of the pump.It is demonstrated how the parameterized model is fully valid to know the behaviour of the pump as long as the operating conditions do not suffer sudden changes. Otherwise, the dynamics to reach the axial clearance balance of the compensation mechanism explains peculiar behaviours which could not have been analysed without the developed tools. The main results of this research have been presented in various papers of Torrent et al., having established an unprecedented methodology applicable to any other type of BDVP.Keywords: pump external gears (BE); experimental parameterization according to ISO standards; modelling with Bond Graph; floating side plates; loss coefficients.
  

• TORRES CHAMORRO, LISBETH ALEJANDRA: Tool-part tribological interaction assessment for continuous deformation processes
  
  Author: TORRES CHAMORRO, LISBETH ALEJANDRA
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Mechanical Engineering (EM)
  Mode: Normal
  Reading date: 03/07/2023
  Thesis director: TRAVIESO RODRIGUEZ, JOSE ANTONIO | CUADRADO LAFOZ, NÚRIA | LLUMA FUENTES, JORDI
  

  Committee:
       PRESIDENT: GÓMEZ GRAS, GIOVANNI
       SECRETARI: JEREZ MESA, RAMON
       VOCAL: WAGNER, VINCENT
  Thesis abstract: This dissertation is an experimental assessment of the tool-part tribological interaction of continuous deformation processes: ball burnishing as a superfinishing process and wire drawing as a bulk deformation process. Through the integration of friction as their fundamental parameter, these processes can be optimized. Thus, after the determination of the coefficient of friction, its impact on the final components surface integrity (hardness, roughness, and residual stresses), as well as the resulting wear mechanisms (adhesion and abrasion) from the sliding contact between hardmetal (WC/Co) and the treated materials (stainless-steel and aluminum alloy), has been analyzed by means of advanced characterization techniques such as: X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive x-ray analysis (EDX) and confocal scanning optical microscopy (CSOM). The results have shown that beyond the operational parameters and the macro-contact conditions, the influence of the micro-contact, microstructure and chemical composition, represent critical points in the tribological behavior of each process. In addition, these experimental outcomes constitute validation tools for numerical models, allowing integral configurations that surpass the simplified models that so far have not achieved adjustments in terms of surface finish and residual stresses, simultaneously. Therefore, potential solutions to the misalignments of each study case have been established from the analysis of a hitherto underestimated factor: friction.
  

• VELÁZQUEZ CORRAL, ERIC: Application of the vibration-assisted ball burnishing process on rotational symmetric parts to improve their fatigue strength and wear properties
  
  Author: VELÁZQUEZ CORRAL, ERIC
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Mechanical Engineering (EM)
  Mode: Change of supervisor
  Reading date: 05/09/2023
  Thesis director: JEREZ MESA, RAMON | LLUMA FUENTES, JORDI | WAGNER, VINCENT
  

  Committee:
       PRESIDENT: BUJ CORRAL, IRENE
       SECRETARI: DUC, EMMANUEL
       VOCAL NO PRESENCIAL: GÓMEZ GRAS, GIOVANNI
  Thesis abstract: This thesis is an experimental investigation into the beneficial effects of the ultrasonic vibration-assisted ball burnishing process on the wear resistance and fatigue life-cycle enhancement of rotational symmetric parts. This study is performedwith a tool patented by the Universitat Politècnica de Catalunya and l¿École Nationale d¿Ingénieurs de Tarbes researchers. A first investigation of the effects of the process is presented, as well an explanation of the analytical performance of each of the process parameters on the main surface integrity descriptors. An experimental campaign is undertaken on AISI 1045,Ti6Al4V and AISI 316L shafts, which are highly appreciated materials on the automotive, biomedical and aeronautical industry. The experimental campaign is based on a Screening design of three factors: burnishing force, number of passes and vibration assistance inputs. Results are analysed in terms of surface integrity factors (microstructure evolution,roughness, hardness and residual stresses) prior to wear and fatigue tests, in order to characterise the resultant surfaces after the process and quantify the contribution of each factor to the final results. The main objective of this dissertation is tocompare the ultrasonic vibration assisted ball burnishing to the traditional ball burnishing and, if so, asses the positive effects of the vibration assistance. Results reveal that surface integrity factors are enhanced when the process is assisted on all materials. Fatigue results show an evidence of an increase of expected fatigue lifetime of AISI 1045 shafts, increasing its fatigue strength by 27 MPa and showing more consistency in results as Weibull statistics evidence. Wear results show that vibration assistance enhances the resistance against a WC-Co ball on the three materials tested, being AISI 316L the most consistent material, under the conditions tested, and demonstrating a relation between the wear volume and the residual stresses measured at the surface after burnishing.
  

Last update: 04/10/2023 05:01:11.

Research groups

• (MC)2-UPC-Computational continuum mechanics
• BIOMEC-Biomechanical Engineering Lab
• CDIF-Center for Industrial Diagnostics
• GReCEF-Grup de Recerca en Ciència i Enginyeria de Fluids
• IAFARG-Industrial and Aeronautical Fluid-dynamic Applications Research Group
• LABSON-Fluid power systems laboratory
• LEAM-Acoustic and Mechanical Engineering Laboratory
• LITEM-Materials and Structures Laboratory of Innovation Technology
• MICROTECH LAB-Microtechnology for the Industry
• RMEE-Strength of Materials and Structural Engineering Research Group
• TECNOFAB-Manufacturing Technologies Research Group
• TUAREG-Turbulence and Aerodynamics in Mechanical and Aerospace Engineering Research Group

Teachers

• Arcos Villamarin, Robert
• Bergadà Granyó, Josep Maria
• Buj Corral, Irene
• Cante Teran, Juan Carlos
• Casals Terre, Jasmina
• Castilla Lopez, Roberto
• Codina Macia, Esteban
• Egusquiza Estevez, Eduard
• Escaler Puigoriol, Xavier
• Font Llagunes, Josep Maria
• Gamez Montero, Pedro Javier
• Gil Espert, Lluis
• Gonzalez Rojas, Hernan Alberto
• Oliver Olivella, Xavier
• Romeu Garbi, Jordi
• Soria Guerrero, Manel
• Travieso Rodriguez, Jose Antonio

• Alvarez del Castillo, Javier
• Amante Garcia, Beatriz
• Balastegui Manso, Andreu
• Comellas Sanfeliu, Ester
• de las Heras Jimenez, Salvador
• Flores Le Roux, Roberto Maurice
• Freire Venegas, Francisco Javier
• Garcia Melendo, Enrique Jose
• Goma Ayats, Juan Ramon
• Guardo Zabaleta, Alfredo
• Hernandez Ortega, Joaquin
• Jofre Cruanyes, Lluís
• Jordi Nebot, Lluïsa
• Lloberas Valls, Oriol
• Lluma Fuentes, Jordi
• Martinez Miralles, Jordi Ramon
• Minguella Canela, Joaquim
• Ortega, Enrique
• Pamies Gomez, Teresa
• Pamies Vila, Rosa
• Porta Pleite, Jose Maria
• Presas Batllo, Alexandre
• Raush Alviach, Gustavo
• Roca Cazorla, David
• Rodriguez Perez, Ivette Maria
• Romeral Martinez, J.L.
• Ros Giralt, Lluis
• Salan Ballesteros, M. Núria
• Sanchez Egea, Antonio Jose
• Sanchez Romero, Montserrat
• Santos Lopez, M. Antonia de los
• Serrancoli Masferrer, Gil
• Torres Camara, Ricardo
• Valentin Ruiz, David
• Veciana Fontanet, Joaquim Maria
• Weyler Perez, Rafael