Damage identification in structural health monitoring: a brief review from its implementation to the Use of data-driven applications

The damage identification process provides relevant information about the current state of a structure under inspection, and it can be approached from two different points of view. The first approach uses data-driven algorithms, which are usually associated with the collection of data using sensors. Data are subsequently processed and analyzed. The second approach uses models to analyze information about the structure. In the latter case, the overall performance of the approach is associated with the accuracy of the model and the information that is used to define it. Although both approaches are widely used, data-driven algorithms are preferred in most cases because they afford the ability to analyze data acquired from sensors and to provide a real-time solution for decision making; however, these approaches involve high-performance processors due to the high computational cost. As a contribution to the researchers working with data-driven algorithms and applications, this work presents a brief review of data-driven algorithms for damage identification in structural health-monitoring applications. This review covers damage detection, localization, classification, extension, and prognosis, as well as the development of smart structures. The literature is systematically reviewed according to the natural steps of a structural health-monitoring system. This review also includes information on the types of sensors used as well as on the development of data-driven algorithms for damage identification.Peer ReviewedPostprint (published version

Ultrasonic sensor for UAV flight navigation

Ultrasonic transducers were utilized for the design and development of an alternative method for flight instrumentation measurement of the velocity of unmanned air vehicles (UAVs). Current methods have been deemed to have significant shortcomings, such as the need for GPS thus leading to indoor UAV operations being incapable of velocity sensing. The proposed concept is developed from the utilization of ultrasonic transit-time flowmeters. A test bench has been produced to measure the accuracy and confirm the validity of the concept. Two key design variables were determined - the optimal transducer mounting configuration and the optimal angle of incidence for the transducer mountings. The mounting configurations were analyzed from common transit-time flowmeter sensor configurations and were tested using both CFD and acoustic simulations. The findings are presented and correlated based on these simulations and it was determined that a V-method configuration was the optimal choice. The correct angle of incidence was determined by an experimental methodology. The time-of-flight outputted from the transducers was compared to the calculated ideal value, and the findings revealed that an angle of 30° was the most accurate for the reflection of the emitted wave. The experimentation was conducted with a specially designed test bench and associated electronic hardware located in a wind tunnel. The test results have provided conclusive evidence that the overall design can produce accurate results comparable with current instrumentation sensors

Cheetah: A Library for Parallel Ultrasound Beamforming in Multi -Core Systems

6 páginas, 2 figuras, 4 tablasDeveloping new imaging methods needs to establish some proofs of concept before implementing them on real -time scenarios. Nowadays, the high computational power reached by multi-core CPUs and GPUs have driven the development of software-based beamformers. Taking this into account, a library for the fast generation of ultrasound images is presented. It is based on Synthetic Aperture Imaging Techniques (SAFT) and it is fast because of the use of parallel computing techniques. Any kind of transducers as well as SAFT techniques can be defined although it includes some pre-built SAFT methods like 2R -SAFT and TFM. Furthermore, 2D and 3D imaging (slicebased or full volume computation) is supported along with the ability to generate both rectangular and angular images. For interpolation, linear and polynomial schemes can be chosen. The versatility of the library is ensured by interfacing it to Matlab, Python and any programming language over different operating systems. On a standard PC equipped with a single NVIDIA Quadro 4000 (256 cores), the library is able to calculate 262,144 pixels in ≈ 105 ms using a linear transducer with 64 elements, and 2,097,152 voxels in ≈ 5 seconds using a matrix transducer with 121 elements when TFM is applied.This work has been supported by the Spanish Government and the University of Alcalá under projects DPI2010- 19376 and CCG2014/EXP -084, respectively.Peer reviewe

A study of methods to predict and measure the transmission of sound through the walls of light aircraft. A survey of techniques for visualization of noise fields

A survey of the most widely used methods for visualizing acoustic phenomena is presented. Emphasis is placed on acoustic processes in the audible frequencies. Many visual problems are analyzed on computer graphic systems. A brief description of the current technology in computer graphics is included. The visualization technique survey will serve as basis for recommending an optimum scheme for displaying acoustic fields on computer graphic systems

Parallelization and improvement of beamforming process in synthetic aperture systems for real-time ultrasonic image generation

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Informática, Departamento de Arquitectura de Computadores y Automática, leída el 9-02-2016La ecografía es hoy en día uno de los métodos de visualización más populares para examinar el interior de cuerpos opacos. Su aplicación es especialmente significativa tanto en el campo del diagnóstico médico como en las aplicaciones de evaluación no destructiva en el ámbito industrial, donde se evalúa la integridad de un componente o una estructura. El desarrollo de sistemas ecográficos de alta calidad y con buenas prestaciones se basa en el empleo de sistemas multisensoriales conocidos como arrays que pueden estar compuestos por varias decenas de elementos. El desarrollo de estos dispositivos tiene asociada una elevada complejidad, tanto por el número de sensores y la electrónica necesaria para la adquisición paralela de señales, como por la etapa de procesamiento de los datos adquiridos que debe operar en tiempo real. Esta etapa de procesamiento de señal trabaja con un elevado flujo de datos en paralelo y desarrolla, además de la composición de imagen, otras sofisticadas técnicas de medidas sobre los datos (medida de elasticidad, flujo, etc). En este sentido, el desarrollo de nuevos sistemas de imagen con mayores prestaciones (resolución, rango dinámico, imagen 3D, etc) está fuertemente limitado por el número de canales en la apertura del array. Mientras algunos estudios se han centrado en la reducción activa de sensores (sparse arrays como ejemplo), otros se han centrado en analizar diferentes estrategias de adquisiciónn que, operando con un número reducido de canales electrónicos en paralelo, sean capaz por multiplexación emular el funcionamiento de una apertura plena. A estas últimas técnicas se las agrupa mediante el concepto de Técnicas de Apertura Sintética (SAFT). Su interés radica en que no solo son capaces de reducir los requerimientos hardware del sistema (bajo consumo, portabilidad, coste, etc) sino que además permiten dentro de cierto compromiso la mejora de la calidad de imagen respecto a los sistemas convencionales...Ultrasound is nowadays one of the most popular visualization methods to examine the interior of opaque objects. Its application is particularly significant in the field of medical diagnosis as well as non-destructive evaluation applications in industry. The development of high performance ultrasound imaging systems is based on the use of multisensory systems known as arrays, which may be composed by dozens of elements. The development of these devices has associated a high complexity, due to the number of sensors and electronics needed for the parallel acquisition of signals, and for the processing stage of the acquired data which must operate on real-time. This signal processing stage works with a high data flow in parallel and develops, besides the image composition, other sophisticated measure techniques (measure of elasticity, flow, etc). In this sense, the development of new imaging systems with higher performance (resolution, dynamic range, 3D imaging, etc) is strongly limited by the number of channels in array’s aperture. While some studies have been focused on the reduction of active sensors (i.e. sparse arrays), others have been centered on analysing different acquisition strategies which, operating with reduced number of electronic channels in parallel, are able to emulate by multiplexing the behavior of a full aperture. These latest techniques are grouped under the term known as Synthetic Aperture Techniques (SAFT). Their interest is that they are able to reduce hardware requirements (low power, portability, cost, etc) and also allow to improve the image quality over conventional systems...Depto. de Arquitectura de Computadores y AutomáticaFac. de InformáticaTRUEunpu

Design and application of reconfigurable circuits and systems

Open Acces

Design of Participatory Virtual Reality System for visualizing an intelligent adaptive cyberspace

The concept of 'Virtual Intelligence' is proposed as an intelligent adaptive interaction between the simulated 3-D dynamic environment and the 3-D dynamic virtual image of the participant in the cyberspace created by a virtual reality system. A system design for such interaction is realised utilising only a stereoscopic optical head-mounted LCD display with an ultrasonic head tracker, a pair of gesture-controlled fibre optic gloves and, a speech recogni(ion and synthesiser device, which are all connected to a Pentium computer. A 3-D dynamic environment is created by physically-based modelling and rendering in real-time and modification of existing object description files by afractals-based Morph software. It is supported by an extensive library of audio and video functions, and functions characterising the dynamics of various objects. The multimedia database files so created are retrieved or manipulated by intelligent hypermedia navigation and intelligent integration with existing information. Speech commands control the dynamics of the environment and the corresponding multimedia databases. The concept of a virtual camera developed by ZeIter as well as Thalmann and Thalmann, as automated by Noma and Okada, can be applied for dynamically relating the orientation and actions of the virtual image of the participant with respect to the simulated environment. Utilising the fibre optic gloves, gesture-based commands are given by the participant for controlling his 3-D virtual image using a gesture language. Optimal estimation methods and dataflow techniques enable synchronisation between the commands of the participant expressed through the gesture language and his 3-D dynamic virtual image. Utilising a framework, developed earlier by the author, for adaptive computational control of distribute multimedia systems, the data access required for the environment as well as the virtual image of the participant can be endowed with adaptive capability

Intelligent Machining Systems

Machining is one of the most widespread manufacturing processes and plays a critical role in industries. As a matter of fact, machine tools are often called mother machines as they are used to produce other machines and production plants. The continuous development of innovative materials and the increasing competitiveness are two of the challenges that nowadays manufacturing industries have to cope with. The increasing attention to environmental issues and the rising costs of raw materials drive the development of machining systems able to continuously monitor the ongoing process, identify eventual arising problems and adopt appropriate countermeasures to resolve or prevent these issues, leading to an overall optimization of the process. This work presents the development of intelligent machining systems based on in-process monitoring which can be implemented on production machines in order to enhance their performances. Therefore, some cases of monitoring systems developed in different fields, and for different applications, are presented in order to demonstrate the functions which can be enabled by the adoption of these systems. Design and realization of an advanced experimental machining testbed is presented in order to give an example of a machine tool retrofit aimed to enable advanced monitoring and control solutions. Finally, the implementation of a data-driven simulation of the machining process is presented. The modelling and simulation phases are presented and discussed. So, the model is applied to data collected during an experimental campaign in order to tune it. The opportunities enabled by integrating monitoring systems with simulation are presented with preliminary studies on the development of two virtual sensors for the material conformance and cutting parameter estimation during machining processes