Scipedia: Julio García-Espinosa's Presentations at Congresses and Seminars

A novel Digital Twin-based Structural Health Monitoring solution for offshore wind turbine platforms

Julio García-Espinosa — Sun, 14 Jan 2024 20:17:47 +0100

This work introduces an innovative Structural Health Monitoring (SHM) solution for offshore wind platforms, featuring an advanced Digital Twin (DT) built on a fully-coupled aero-servo-hydro-elastic model. Our approach utilizes a detailed Finite Element model of the structure, meeting the requirements of the main assessment/certification standards. The application of the unique Enriched Modal Matrix Reduction technique leads substantially reduces CPU time, enabling near real-time calculations without compromising accuracy compared to the original FE model.

The SHM system is completed with an optimized sensors setup to monitor the most relevant deformation modes. Additionally, it enables precise fine-tuning of the DT model using machine learning, resulting in an accurate Hybrid Analysis Model.

Our modular and flexible DT-based SHM solution can be customized for any offshore wind platform concept, covering substructure, towers, mooring, and umbilicals. The solution is demonstrated through sea trials on Enerocean’s W2Power prototype.

Introduction to FIBREGY project

Julio García-Espinosa — Mon, 25 Jan 2021 19:09:03 +0100

The overall objective of the FIBREGY project is to enable the extensive use of FRP materials in the structure of the next generation of large Offshore Wind and Tidal Power platforms. In order to achieve this objective, the project will develop, qualify and audit innovative FRP materials for offshore applications, elaborate new design procedures and guidelines, generate efficient production, inspection and monitoring methodologies, and validate and demonstrate advanced software analysis tools. Finally, the different developed technologies will be demonstrated by using advanced simulation techniques and building large and real-scale prototypes.

A second-order semi-Lagrangian particle FEM (SL-PFEM) method for the incompressible Navier-Stokes equations

Julio García-Espinosa — Thu, 13 Feb 2020 20:01:02 +0100

The Semi-Lagrangian Particle Finite Element Method (SL-PFEM) is a numerical method tailored for solving the fluid dynamics equations. Despite of its excellent numerical properties, such as a minimum numerical erosion in the convective transport and that it exhibits great stability, it has not yet received much attention in the scientific literature. In this presentation, a second order SL-PFEM scheme for solving the incompressible Navier-Stokes equations is presented. This scheme is based on the second order velocity Verlet algorithm, which uses an explicit integration for the particle’s trajectory and an implicit integration for the velocity. The algorithm is completed with a predictor-multicorrector scheme for the integration of the velocity correction using the Finite Element Method. A second order projector based on least squares is used to transfer the intrinsic variables information from the particles onto the background mesh, while a second order interpolation scheme is used to transfer the pressure gradient and viscous accelerations from the mesh to the particles.

ODDLS: An overlapping domain decomposition level set method for simulation of free surface problems

Julio García-Espinosa — Thu, 12 Dec 2019 18:39:02 +0100

This presentation introduces a new stabilized finite element method based on the finite calculus (Comput. Methods Appl. Mech. Eng. 1998; 151:233–267) and arbitrary Lagrangian–Eulerian techniques (Comput. Methods Appl. Mech. Eng. 1998; 155:235–249) for the solution to free surface problems. The main innovation of this method is the application of an overlapping domain decomposition concept in the statement of the problem. The aim is to increase the accuracy in the capture of the free surface as well as in the resolution of the governing equations in the interface between the two fluids. Free surface capturing is based on the solution to a level set equation. The Navier–Stokes equations are solved using an iterative monolithic predictor–corrector algorithm, where the correction step is based on imposing the divergence‐free condition in the velocity field by means of the solution to a scalar equation for the pressure. Examples of application of the ODDLS formulation (for overlapping domain decomposition level set) to the analysis of different free surface flow problems are presented.

Advances in the Simulation of Ship Navigation in Brash Ice

Julio García-Espinosa — Thu, 19 Jul 2018 22:55:52 +0200

Brash ice is the accumulation of floating ice made up of blocks no larger than two meters across. Navigation in brash ice is becoming more usual as new navigation routes are being opened in the Artic regions. This navigation brings new concerns regarding the interaction of ice blocks with the ship. This work presents recent advances towards the development of a computational model for simulation of this navigation condition including the interaction among the ship and the ice blocks.

The computational tool developed in this work is based on the coupling of a Semi-Lagrangian Particle Finite Element Method (SL-PFEM) with a multi rigid-body dynamics tool. The Particle Finite Element Method (Idelsohn et al. 2004) is a versatile framework for the analysis of fluid-structure interaction problems. The PFEM combines Lagrangian particle-based techniques with the advantage of the integral formulation of the Finite Element Method (FEM). It has been shown (Idelsohn et al. 2014 and Nadukandi et al. 2017) to successfully simulate a wide variety of complex engineering problems, e.g. free-surface/multi-fluid flows with violent interface motions, multi-fluid mixing and buoyancy-driven segregation problems etc.

The latest development within the framework of the PFEM is the X-IVAS (eXplicit Integration along the Velocity and Acceleration Streamlines) scheme. It is a semi-implicit scheme built over a Semi-Lagrangian (SL) formulation of the PFEM.

In this work, the SL-PFEM model has been coupled with a multibody dynamics solver, able to handle the interactions between thousands of bodies, representing the different ice blocks. The interaction between the fluid flow and the ice blocks is taking into account by enriching the finite element space at the boundaries of the different blocks.

This work is part of the research project NICESHIP sponsored by the U.S. Office of Naval Research under Grant N62909-16-1-2236.

Advances in the Simulation of Ship Navigation in Ice

Julio García-Espinosa — Tue, 19 Jun 2018 00:03:03 +0200

This work is part of the research project NICESHIP sponsored by the U.S. Office of Naval Research under Grant N62909-16-1-2236.

A finite element method for hydrodynamic testing of ship forms

Julio García-Espinosa — Wed, 28 Mar 2018 09:56:48 +0200

This paper presents advances in recent work of the authors to derive a fractional step scheme based on the stabilized finite element method that allows overcoming the above mentioned problem, resulting in a efficient time accurate scheme.

The starting point is the modified governing differential equations for the incompressible turbulent viscous flow and the free surface condition incorporating the necessary stabilization terms via a finite calculus (FIC) procedure developed by the authors . This technique is based on writting the different balance equations over a domain of finite size and retaining higher order terms. These terms incorporate the ingredients for the necessary stabilization of any transient and steady state numerical solution already at the differential equations level.

The resulting stabilized equations are integrated in space using the standard finite element method, and in time using an implicit and uncoupled second order fractional step method.

Nonlinear Finite Element Analysis of Mooring Cables on Marine Structures

Julio García-Espinosa — Mon, 05 Mar 2018 21:33:13 +0100

The complexity of the dynamic response of offshore marine structures requires advanced simulations tools for the accurate assessment of the seakeeping behaviour of these devices. This presentation introduces a new time-domain model for solving the dynamics of moored floating marine devices, specifically offshore wind turbines, subjected to non-linear environmental loads.

Different application examples are presented,including a GVA, and the OC3 and OC4 platforms.

Your Open Science and Research Publishing Platform

Julio García-Espinosa — Mon, 27 Nov 2017 22:22:02 +0100

Scipedia is an innovative Open Science and Research Publishing Platform. Scipedia aims to connect researchers and professionals in science and technology and facilitate the sharing of knowledge, expertise and the outcome of their work.

Scipedia.com was born to offer a complete solution for open science, and essentially integrates three solutions:

An online scientific editorial platform for journals and data repositories.
A web publishing system and online edition of collaborative scientific documents.
A collaborative social network focused on scientists and professionals in science and technology.

This presentation introduces the solutions offered by Scipedia for the needs of open science projects, and the advantages of the platform for researchers, institutions and scientific journals.

Challenges on computational models for ship design and navigation: Ongoing projects at CIMNE MARINE

Julio García-Espinosa — Sat, 18 Nov 2017 17:03:45 +0100

This presentation shows the recent work of the CIMNE in the maritime transport field. It was given at the Conference on Computation and Big Data in Transport (CM3-2017) held in November 22 – 23, 2017.

A computational model for the evaluation of the spray generation of a Wave Adaptive Modular Vessel

Julio García-Espinosa — Tue, 08 Aug 2017 20:24:11 +0200

A Wave Adaptive Modular Vessel (WAM-V®) is a new class of ship that uses inflatable flexible hulls to conform to the surface of the water. It is similar in design to a catamaran, in that it has a twin hull design and no keel. However, the superstructure is not rigidly attached to the hulls; it uses shock absorbers and ball joints to articulate the vessel, which allows WAM-V to conform to the surface of the water while mitigating the stresses transmitted to the structure. Moreover, the inflatable hulls help to absorb the high frequency wave-loads. These features allow WAM-V to travel efficiently with low wave resistance in rough seas, by surfing on top of the waves rather than cut through them.

The objective of the WAM-V is to be a lightweight watercraft capable of moving fast and efficiently on the surface of the sea. WAM-Vs are designed to allow for a variety of applications for either manned or unmanned operations and can be built in different lengths to match specific services.

This presentation shows part of the work done in the project ‘Advanced Numerical Simulation and Performance Evaluation of WAM-V ® in Spray Generating Conditions’ developed by the International Center for Numerical Methods in Engineering (CIMNE) under Navy Grant N62909-12-1-7101 issued by the Office of Naval Research Global. The scope of that project included the performance analysis of the WAM-V in waves, taking into account the flexibility of the ship hulls, using fluid-structure interaction computational models. However, the focus of this paper is one of the primary concerns of that project; the development of a computational model for simulation of the WAM-V under spray generating conditions. In this regards, the final goal was to develop and demonstrate a computational engineering solver that could be used to design strategies to reduce the spray generation of the vessel.

Evaluating performance of the air cushion and seals of a Surface-Effect Ship (SES)

Julio García-Espinosa — Tue, 08 Aug 2017 20:57:55 +0200

This presentation shows the recent work of the authors in the development of a time-domain FEM model for evaluation of the seal dynamics of a surface effect ship. The fluid solver developed for this purpose, uses a potential flow approach along with a stream-line integration of the free surface. The presentation focuses on the free surface-structure algorithm that has been developed to allow the simulation of the complex and highly dynamic behavior of the seals in the interface between the air cushion, and the water.

The developed fluid-structure interaction solver is based, on one side, on an implicit iteration algorithm, communicating pressure forces and displacements of the seals at memory level and, on the other side, on an innovative wetting and drying scheme able to predict the water action on the seals. The stability of the iterative scheme is improved by means of relaxation, and the convergence is accelerated using Aitken’s method.

Several validations against experimental results have been carried out to demonstrate the developed algorithm.

Coupled wave-structure analysis for naval and offshore applications

Julio García-Espinosa — Tue, 08 Aug 2017 21:20:02 +0200

Wave-structure interaction is a topic of great interest in naval and offshore engineering. This interest is growing in the last years due to the boost given by the development of the marine renewable energy field. In this context the development of an efficient time-domain coupled waves-structure solver is a main request from the industry.

Up to date the numerical seakeeping simulation has been mostly carried out using the frequency domain. The reason might be that the computational cost of time domain simulations were too high and computational time was too large. Moreover assumptions like linear waves and the harmonic nature of water waves made the frequency domain to be the right choice. However nowadays computing capabilities make possible to carry out numerical simulations in the time domain in a reasonable time, with the advantage of making easier the introduction of non-linearities into the algorithm and therefore coupling with other phenomena.

This presentation shows the work of the authors in developing a time-domain unstructured Finite Element Method (FEM) algorithm for analysis of coupled wave-structure interaction. For this purpose, a new diffraction-radiation solver using the FEM was developed. The solver has been implemented in GPU, using CUDA architecture. The speed-up obtained ranges from 5 to 10 times compare to the implementation in a standard CPU with a conjugate gradient and ILU preconditioner.

The seakeeping analysis tool has been integrated within a coupled waves-structure analysis tool. The coupling algorithm is based on a partitioned iterative algorithm, using an interpolation library able to communicate pressure forces and displacements of the structure at memory level. Furthermore, an innovative wetting and drying scheme able to improve the evaluation of the water action on the structure.

The accuracy of the new seakeeping formulation for analysis of waves and floating structures interaction has been verified in different validation cases and practical applications.

Scipedia.com: Your Open Science Digital Publisher

Julio García-Espinosa — Thu, 27 Apr 2017 09:49:01 +0200

Some of the most relevant facts that are affecting the scientific publication and its impact are the transformations that have begun to happen in relation to what has been called Open Science. This represents a new approach to the scientific process, which is based on cooperative work and is inevitably linked to Open Access publishing. And although the latter term is linked to immediate and free access to research articles, it has evolved towards a much more complete concept involving the transformation of scientific practice to "share knowledge as soon as possible". The transformation towards Open Science has been assumed by the European Commission, which carrying out different measures in this regard.

But, despite the obvious advantages of Open Access publishing, it will not be an easy task to make search results universally accessible without restriction. This objective faces the inertia of custom practices and a market dominated by a few large publishers.

The idea of developing a platform to answer many of the questions raised about the future of scientific publication is the outcome of many reflections and discussions on the presented scenario.

Scipedia (see http://www.scipedia.com) is essentially a web platform that integrates a digital scientific publishing platform with the concept of social network. Scipedia aims to improve communication between researchers and professionals in science and technology, facilitating the exchange of knowledge and dissemination of their work.

The ambition of this project is to be able to offer free publication services in Open Access to the entire scientific community. To this end, Scipedia integrates tools that allow the publication of journals and the management of their publication cycle, including support for blind and collaborative peer review.

But probably one of the most innovative aspects of this initiative is that it uses wikitext, a standard format for web pages, as a native format of publications. This definitely allows going beyond the paper support and its digital versions (such as the PDF format); the scientific communication can take full advantage of the publication on the Internet. This way, scientific journals and books, conference proceedings and any other document published in Scipedia can integrate text, multimedia information, data files, models, etc. in a natural way.

In addition, Scipedia has an advanced online editor that allows for collaborative work and facilitates self-publishing. The capacity of self-publishing is not a trivial matter, since it virtually reduces production and publication costs to zero, and is basic to fulfilling the project's main ambition: to offer free publishing services for the author and open access without restrictions.

The online editing tool is completed with utilities for importing files in LaTeX and Word formats, and exporting to PDF and ePub.

Another relevant aspect of the initiative is that various strategies have been designed that allow articles to reach the maximum impact. For this, it is not enough to comply with certain standards and procedures that facilitate their indexation in the main search engines and aggregators. Here, the integration of the platform into a social network can play a fundamental role.

Scipedia social network offers the standard tools of this type of platforms, creation of a user profile, creation of a network of contacts, presentation of the register of personal activities and of the contacts, creation and management of groups, etc. The basic information of the profile can be imported and synchronized with the data available in Google Scholar, which provides a first reference of the impact of the scientific activity of the user. This information is enriched with that generated by the personal activity in the network, which is dynamized using gamification techniques. This way, the actions of the user are rewarded and allow to evaluate the activity that generates in the network. In addition, records of visits and ratings of readers of an article are kept, which together with more traditional techniques such as citation counting, allows you to evaluate the impact of any document. In addition, each published document has a discussion page attached, and a history of all its revisions is maintained, even beyond the date of its publication.