Documents published in Scipedia

• Methodology and application to assess thermo-mechanical buckling in composite marine structures.

  R. Pacheco, D. Capua, J. García, O. Casals

  Collection of Métodos de Test (2022). 1

  
  

  Abstract

  This paper describes the behaviour of large-length ships built using fibre-reinforced plastic composite materials under fire and large deformations. A novel methodology is proposed in order to analyse inelastic buckling and post-buckling of steel structures due to thermal loading and also extend this to the phenomenon regarded as pyrolysis that is natural in composite structures. The methodology is validated against the literature. A model of a container-ship where a fire scenario located in the engine room is used to demonstrate the methodology against a real case scenario. The section of the cargo hold closest to the engine room is structurally analysed, focusing in the integrity of the bulkhead and the supports of the TEU containers.This paper describes the research performed within the scope of H2020 project FIBRE4YARD in the development of a suitable thermo-mechanical framework to analyse composite structures under fire loads. The thermo-mechanical model uses the adiabatic temperature to obtain the through-thickness distribution of temperature of the triangular shell element, this formulation is able to predict phenomena such as pyrolysis, thermo-mechanical yielding and large displacements (non-linear buckling). An application case of a load-bearing section of a container ship is shown to demonstrate the correctness of the methodology, two type of materials are considered in the analysis, traditional materials such steel and advanced materials like fibre reinforced plastic (FRP) composites.

  Abstract
  This paper describes the behaviour of large-length ships built using fibre-reinforced plastic composite materials under fire and large deformations. A novel methodology is [...]

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• Critical-comparative study of advertisements from a gender perspective as a didactic proposal in Social Sciences

  J. Donoso

  Collection of Métodos de Test (2021). 14

  
  

  Abstract

  The following article addresses the objectification and instrumentalization of women through advertisements, advocating new critical ways of looking. For this, a comparative proposal of advertisements in the dictatorships and later democracy of Romania and Spain is made. In this way, a perspective is generated that, regardless of their differences, shows how patriarchy and its distribution of roles spread in both countries and a critical awareness is stimulated to transform the subordinate position of women in the family sphere. economic, social, political, cultural and historical.

  Abstract
  The following article addresses the objectification and instrumentalization of women through advertisements, advocating new critical ways of looking. For this, a comparative [...]

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• A Taylor -Galerkin method for the use of finite elements in a nonlinear problem for the numerical modeling of a new Chemo-Fluid oscillator.

  I. Alvarez

  Collection of Métodos de Test (2021). 12

  
  

  Abstract

  In this work, a finite element scheme is proposed using a method of Euler-Taylor-Galerkin described in [1], for a non-linear model which describes the behavior of a new chemo-fluidic oscillator, [2]. This model is expressed by the coupling of an ordinary differential equation describing the hydrogel dynamics, the non-linear transport equation and an auxiliary equation determining the flux volume. The numerical solution is constructed by taking a semi-discretization in time of the transport equation, employing forward-time Taylor series expansions including time derivatives of second order and third order, avoiding instabilities problems.  In this semi discrete equation, the spatial variable is approximated by the finite element formulation according to Galerkin. Some simulations are carried out taking different initial conditions for the concentration of the hydrogel. The numerical results describes the oscillatory behavior of the system as in [2], where MatLab tools are used as black box.

  Abstract
  In this work, a finite element scheme is proposed using a method of Euler-Taylor-Galerkin described in [1], for a non-linear model which describes the behavior of a new chemo-fluidic [...]

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• Goal-Oriented Inverse Analysis - Application to Building Thermal Problems

  L. Chamoin, Z. Djatouti, J. Waeytens, P. Chatellier

  Congress Test - Abstracts.

  
  

  Abstract

  We present an original goal-oriented inverse method for model parameter identification. Initially developed in [1], it is based on dual analysis and consists in a modified version of the concept of Constitutive Relation Error. It stands out from standard deterministic inverse methods by its formulation, as it focuses on the accurate prediction of a specific quantity of interest, and aims at automatically identifying and updating the model parameters involved in its computation alone. To further reduce the CPU time of the multi-query inversion process, that also involves coupled time forward/backward systems to solve, the goal-oriented inverse method is beneficially complemented with model order reduction, using the Proper Generalized Decomposition (PGD) technique [2]. Eventually, the goal-oriented method is also employed for optimal sensor placement (experimental design), in order to drastically reduce the number of sensors which need to be deployed for the objective of the simulation. The proposed method is here applied and illustrated with transient heat transfer models encountered in building thermal problems. Inverse analysis with such models is a compulsory but costly task for the reliable evaluation of building thermal properties, accurate prediction of energy consumption, and therefore optimal driving of renovation strategy of power control. It usually involves a large number of parameters but a restricted number of available sensing data. In this framework, the goal-oriented method is first integrated in a software chain containing CAD and thermal dynamic simulation tools. Performance is then numerically evaluated on several test cases with real experiments. In particular, a two-story building of the Sense-City equipment with controlled climate scenarios and in-situ sensors is considered, with various quantities of interest [3]. It is shown that for all these and using the goal-oriented strategy, very few model parameters actually need to be updated, and little sensing information is necessary, without sacrificing accuracy. It is then a tool of choice for such applications.

  Abstract
  We present an original goal-oriented inverse method for model parameter identification. Initially developed in [1], it is based on dual analysis and consists in a modified [...]

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• Pandeo lateral de vigas de acero. Análisis comparado de las normas CTE DB SE-A, EAE y EC3

  C. García

  Collection of Métodos de Test (2021). 11

  
  

  Abstract

  The Basic Document, Structural Safety, Steel of the Spanish Technical Building Code provides mathematical expressions to obtain the lateral buckling resistance of hot-rolled steel beams. These expressions include a coefficient, C1, that accounts for variation of the bending moment along the beam. However, this document only provides values for linear diagrams of bending moments. The instruction for Structural Steel, a copy of the latest version of Eurocode 3, does not include any method to obtain the elastic critical moment. On the contrary, a table with correction factors applicable to different types of bending moments diagrams is included. In this document both procedures have been combined and results have been compared to those obtained using other versions of the Eurocode 3. Finally, tables have been provided to ease the design of hot-rolled steel beams while preventing the lateral buckling.

  Abstract
  The Basic Document, Structural Safety, Steel of the Spanish Technical Building Code provides mathematical expressions to obtain the lateral buckling resistance of hot-rolled [...]

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• Computational Modeling of The Mechanics of Energy Harvesters Based On Tensegrity Solar Façades

  R. Miranda, E. Babilio, N. Singh, F. Santos, F. Fraternali

  Collection of Métodos de Test (2021). 9

  
  

  Abstract

  This work is focused on the computational design of tensegrity shading systems of energy efficient buildings which mitigate air conditioning consumption and optimize the energy performance of the building. It is concerned with the design of active solar façade screens based on lightweight tensegrity units, which are easily integrated with energy harvesting piezoelectric cables. The unit cells of the analyzed screens are controlled by tensioning and releasing selected cables of the structure. A numerical procedure simulates the dynamics of the analyzed tensegrity façades, by considering the opening and closure motions of the screens, and the vibrations produced by the action of dynamic wind forces. The energy harvesting ability of the proposed façade is numerically estimated.

  Abstract
  This work is focused on the computational design of tensegrity shading systems of energy efficient buildings which mitigate air conditioning consumption and optimize the energy [...]

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• Computational modeling of the seismic response of tensegrity dissipative devices incorporating shape memory alloys

  N. Singh, A. Amendola, G. Benzoni, F. Fraternali

  Collection of Métodos de Test (2021). 8

  
  

  Abstract

  Infrastructures and buildings must have sufficient protection for design level earthquake excitations while minimizing major damage to comply with existing seismic design criteria. This paper explores the computational modeling of a tensegrity based brace, which helps dissipate energy while preventing inter-story drifts. The proposed brace integrates a D-bar tensegrity structure, shaped like a rhombus, with Shape-Memory Alloy (SMA) cables or tendons. These tendons grow austenitic-martensiticaustenetic (solid to solid) transformations, which make them more susceptible to mechanical stress when taking strain, and amplifying the stress into broad superelastic hysteresis, even after repeated mechanical cycles that require strains of up to 6% 8%. In addition in this article two special classes of the tensegrities are discussed namely 2D and 3D braces. 3D braces have been proven more efficient because of an enhaced capacity of energy dissipation, and also due to their improved safety against buckling. The effectiveness of the planned bracing paves the way to the development of innovative systems of seismic energy dissipation that combine tensegrity concepts with superelasticity.

  Abstract
  Infrastructures and buildings must have sufficient protection for design level earthquake excitations while minimizing major damage to comply with existing seismic design [...]

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• COMPUTATIONAL MODELING OF THE SEISMIC RESPONSE OF TENSEGRITY DISSIPATIVE DEVICES INCORPORATING SHAPE MEMORY ALLOYS

  N. Singh, A. Amendola, G. Benzoni, F. Fraternali

  Collection of Métodos de Test (2021). 7

  
  

  Abstract

  Infrastructures and buildings must have sufficient protection for design level earthquake excitations while minimizing major damage to comply with existing seismic design criteria. This paper explores the computational modeling of a tensegrity based brace, which helps dissipate energy while preventing inter-story drifts. The proposed brace integrates a D-bar tensegrity structure, shaped like a rhombus, with Shape-Memory Alloy (SMA) cables or tendons. These tendons grow austenitic-martensiticaustenetic (solid to solid) transformations, which make them more susceptible to mechanical stress when taking strain, and amplifying the stress into broad superelastic hysteresis, even after repeated mechanical cycles that require strains of up to 6% 8%. In addition in this article two special classes of the tensegrities are discussed namely 2D and 3D braces. 3D braces have been proven more efficient because of an enhaced capacity of energy dissipation, and also due to their improved safety against buckling. The effectiveness of the planned bracing paves the way to the development of innovative systems of seismic energy dissipation that combine tensegrity concepts with superelasticity.

  Abstract
  Infrastructures and buildings must have sufficient protection for design level earthquake excitations while minimizing major damage to comply with existing seismic design [...]

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• Remote Sensing for a Lining Integrated Active Structural Acoustic Control System

  M. Misol, S. Algermissen

  Collection of Métodos de Test (2021). 6

  
  

  Abstract

  In the framework of the EU project ACASIAS an aircraft sidewall panel (lining) with structurally integrated actuators and sensors is developed. Each lining has a digital unit which samples the sensor signals, performs filtering operations and supplies the actuators with control signals. The whole system makes up an active structural acoustic control system aiming at the reduction of low-frequency multi-tonal aircraft interior noise. The novelty of this approach compared to past implementations of active noise control (ANC) systems in aircraft is its modularity. Each so-called smart lining is autonomous in the sense that it processes only structural sensor data from its own integrated sensors. The use of external microphones for error sensing is avoided because this conflicts with the modularity of the smart lining. Hence, one important design task is the replacement of the physical error microphones by the integrated structural sensors and an acoustic filter (observer) running on the digital unit. This method, which is called the remote microphone technique for active control, has never been applied to an aircraft interior structure so far. The detailed design of the smart lining module comprises several steps which are taken within work package 3 of the ACASIAS project. Experimental data of an aircraft typical double panel system is captured in a sound transmission loss facility. The system is excited with a loudspeaker array placed directly in front of the fuselage structure. Different acoustic load cases are used for the definition of the sensors and the actuators. A multi-tonal excitation with high sound pressure level is relevant for the actuator dimensioning and a broadband excitation with multiple independent sound sources is relevant for the sensor definition. 19 accelerometers are mounted on the lining and 20 microphones are placed in front of it. All sensor signals are sampled simultaneously for deterministic and broadband load cases. The lining is equipped with two inertial mass actuators which are used for the active control. Measured frequency response functions of actuators at 39 positions are used for the optimization of the actuator locations. The measurement data is also used for the derivation of an observer and for the simulation of a smart lining with remote microphones. In this contribution, the steps undertaken for the detailed design will be described and simulation results of the noise reduction performance of the smart lining with remote microphones will be presented.

  Abstract
  In the framework of the EU project ACASIAS an aircraft sidewall panel (lining) with structurally integrated actuators and sensors is developed. Each lining has a digital unit which [...]

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• Towards a Lining Integrated Active Structural Acoustic Control System

  S. Algermissen, M. Misol, A. Kokott, T. Haase, K. Gonet, V. Lungaho

  Collection of Métodos de Test (2021). 4

  
  

  Abstract

  For future aircraft counter-rotating open rotor (CROR) engines are a promising technology to reduce their CO2 footprint. Since the contribution of CROR engines to the cabin noise is higher than for jet engines, new strategies for the reduction of noise transmissions for frequency bands below 500 Hz are necessary. Active structural acoustic control (ASAC) systems are capable to reduce sound transmission of lining structures in this bandwidth. Sensors measure the vibrations of the lining to estimate its sound emission into the cabin. Based on these signals a controller calculates force signals for actuators on the lining. The actuator forces change the vibration behaviour of the lining in order to reduce its sound emission. For the realization of such a system in a real aircraft, manufacturing and maintenance issues have to be addressed. Within work package 3 of the EU project ACASIAS an aircraft lining with an integrated ASAC system is developed. The size of the lining is app. 1300 x 1690 mm2 (W x H) and it is simply curved. The radius of 2980 mm makes it relevant for a twin-aisle aircraft like the Airbus A350. The focus of research activities lies on the integration of components and the industrial manufacturing process of the lining. The components to be integrated are sensors, actuators and the corresponding wiring. A concept is proposed where each actuator and sensor is encapsulated in a kind of insert. The inserts smoothly integrate into the manufacturing process of the lining while they protect the actuators and sensors from humidity, dust, etc. The maintenance aspect is covered by the option to change each actuator or sensor upon insert level. The integrated wiring of the lining is left unaffected during an actuator or sensor replacement since connectors in each insert allow a nearly tool-free assembly/disassembly. In this paper the progress of work package 3 is presented at a detailed design review (DDR) stage. Finally, the lining will be manufactured and equipped with a full ASAC system. Experiments will be conducted in the acoustic transmission loss facility at the DLR.

  Abstract
  For future aircraft counter-rotating open rotor (CROR) engines are a promising technology to reduce their CO2 footprint. Since the contribution of CROR engines to the cabin [...]

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