Gerardo Aranguren

Comparing polymer optical fiber, fiber Bragg grating, and traditional strain gauge for aircraft structural health monitoring

Systems for structural health monitoring in aeronautical structures use methods of measuring the elongation that normally require too heavy setups or difficult assembly jobs, such as those based on traditional strain gauges. Alternative methods based on fiber Bragg gratings tend to be very expensive. We analyze the possibility of improving the existing designs with the aid of low-cost plastic optical fiber sensors. For this purpose we test these sensors in a rudder flap subjected to different types of bending forces. The results show that they offer good stability and repeatability, and the measured values are very similar to those obtained with Bragg sensors.

Ultrasonic wave-based structural health monitoring embedded instrument

Piezoelectric sensors and actuators are the bridge between electronic and mechanical systems in structures. This type of sensor is a key element in the integrity monitoring of aeronautic structures, bridges, pressure vessels, wind turbine blades, and gas pipelines. In this paper, an all-in-one system for Structural Health Monitoring (SHM) based on ultrasonic waves is presented, called Phased Array Monitoring for Enhanced Life Assessment. This integrated instrument is able to generate excitation signals that are sent through piezoelectric actuators, acquire the received signals in the piezoelectric sensors, and carry out signal processing to check the health of structures. To accomplish this task, the instrument uses a piezoelectric phased-array transducer that performs the actuation and sensing of the signals. The flexibility and strength of the instrument allow the user to develop and implement a substantial part of the SHM technique using Lamb waves. The entire system is controlled using configuration software and has been validated through functional, electrical loading, mechanical loading, and thermal loading resistance tests.

Hardware implementation of a pipeline fuzzy controller and software tools

This article describes a pipeline sequential fuzzy controller endowed with great flexibility and high performance. Its design allows for the possibility to implement it on programmable devices at low cost. To optimise the design and performance of the circuit, a number of simplifications over traditional fuzzy algorithms are pointed out. For the manipulation of simplification procedures, some software tools of knowledge acquisition and compilation have been developed. The hardware design is presented at a level of block diagram showing the different components and the solutions adopted in each case. The characteristics of this design make it adequate for working with a great number of input and output variables and with a high number of rules. Under these conditions, the speed of calculation and the circuit dimensions are optimal. It can be used in any field of application where a fuzzy control of high complexity is to be established.

Slave node architecture for train communications networks

In this paper we present a new architecture for slave node of a train communication system based on the standard TCN (train communication network). This node is used to interconnect different electronic equipment based on the MVB (multifunction vehicle bus). The architecture is based on a microcontroller for the link and network layers, and a PLD for the implementation of the physical layer.

Modeling of the data transportation network of a multi-hop data-content-sharing home network

This paper demonstrates the implementation of indoor Bluetooth communication multi-hop networks. Since the performance of such networks determines the range of applications that they can support, the performance of Bluetooth wireless multi-hop networks is a common topic of interest. Communication network models are widely used to estimate the performance of networks in many different aspects. This paper focuses on one of the aspects, i.e., the time performance of the data transportation network of a Bluetooth multi-hop home network, and provides a novel empirical model for latency in multi-hop networks with asynchronous links when links are active. The model offers a sharp estimation of the latency added with every hop in the communication such that electronics product designers and network managers can effectively run time-constrained applications in this type of network. The model is based on the results from experiments carried out on a real test bed. The test bed includes Bluetooth nodes and proprietary middleware at the HCI (Host Controller Interface) level of communication. The experimental results show that the time performance worsens with an increasing number of hops in the communication and additionally provide evidence of the quadratic dependence on the number of hops exhibited by the latency 1.

Proof of Concept of Impact Detection in Composites Using Fiber Bragg Grating Arrays

Impact detection in aeronautical structures allows predicting their future reliability and performance. An impact can produce microscopic fissures that could evolve into fractures or even the total collapse of the structure, so it is important to know the location and severity of each impact. For this purpose, optical fibers with Bragg gratings are used to analyze each impact and the vibrations generated by them. In this paper it is proven that optical fibers with Bragg gratings can be used to detect impacts, and also that a high-frequency interrogator is necessary to collect valuable information about the impacts. The use of two interrogators constitutes the main novelty of this paper.

Using bogie-mounted sensors to measure wheel rolling and sliding on railway tracks

The goal of this paper is to present both the development of an intelligent sensor that can be used to obtain information about the existence of rolling contact fatigue cracks created by wheel–rail interactions and also the data obtained in a real-world study performed for its validation. The design of a bogie-mounted instrumentation system to detect and measure wheel rolling in railway units is introduced, and experimental results are presented. The system is designed to analyse and compare the angular velocity of the wheels of a railway unit. It uses photodiodes to acquire information about rolling conditions and a radio frequency link to send that information to a data logger, which acquires and saves the data for post-processing and analysis.

Note: Methodology for the analysis of Bluetooth gateways in an implemented scatternet.

This Note introduces a novel methodology to analyze the time performance of Bluetooth gateways in multi-hop networks, known as scatternets. The methodology is focused on distinguishing between the processing time and the time that each communication between nodes takes along an implemented scatternet. This technique is not only valid for Bluetooth networks but also for other wireless networks that offer access to their middleware in order to include beacons in the operation of the nodes. We show in this Note the results of the tests carried out on a Bluetooth scatternet in order to highlight the reliability and effectiveness of the methodology. The results also validate this technique showing convergence in the results when subtracting the time for the beacons from the delay measurements.

The electronic production: A notable absence from the university

The goal of the study presented in this paper is to emphasize the importance of the knowledge of the manufacturing processes to the engineering students. Printed circuit board manufacturing and circuit assembly are essential issues in the electronics field. Below, some previous experiences are introduced, and the necessary knowledge and planning of a subject in the new curriculum are also proposed.

Comparing Polymer Optical Fiber (POF), fiber Bragg gratings and traditional strain gauge for aircraft structural health monitoring

Recently, the Polymer Optical Fiber Application Center (POF AC) at the University of Applied Sciences, Nuremberg has developed a polymer optical fiber (POF) elongation sensor. This work analyzes if this design could substitute the traditional strain gauges that are commonly used in structural health monitoring (SHM) tests, or the quite recent sensors based on fiber Bragg gratings.