M. García-Diéguez

Active Wireless System for Structural Health Monitoring Applications.

The use of wireless sensors in Structural Health Monitoring (SHM) has increased significantly in the last years. Piezoelectric-based lead zirconium titanate (PZT) sensors have been on the rise in SHM due to their superior sensing abilities. They are applicable in different technologies such as electromechanical impedance (EMI)-based SHM. This work develops a flexible wireless smart sensor (WSS) framework based on the EMI method using active sensors for full-scale and autonomous SHM. In contrast to passive sensors, the self-sensing properties of the PZTs allow interrogating with or exciting a structure when desired. The system integrates the necessary software and hardware within a service-oriented architecture approach able to provide in a modular way the services suitable to satisfy the key requirements of a WSS. The framework developed in this work has been validated on different experimental applications. Initially, the reliability of the EMI method when carried out with the proposed wireless sensor system is evaluated by comparison with the wireless counterpart. Afterwards, the performance of the system is evaluated in terms of software stability and reliability of functioning.

Development of a Behaviour Curve for Quality Evaluation with Optoelectronic Profilometers

This work shows an experimental procedure aimed to generate a graph with the optimal roughness parameters in order to obtain the best roughness measurements of an optoelectronic profilometer. The optimal parameters have been determined taking into account the grade of agreement between the optical roughness values and the equivalent values of traditional contact devices. The working parameters of the optoelectronic profilometer are based on computational filters which are controlled by software working with a 3D stratified colour map (chromatic fragmentation of the white light). However, these parameters substantially differ from the usual contact profilometers that work with 2D roughness profiles (cut-off, evaluation length and contact stylus radii). This work pursues to find the optical profilometer parameters, and its values, that ensure the best quality measurement for a wide range of machining process and testing several ISO roughness intervals.

Statistical Modeling of the Relationships between Spatiotemporal Parameters of Human Walking and Their Variability

AbstractHuman walking is a decisive excitation when checking vibration serviceability of several kinds of structures. Advanced models of walking load are needed to obtain realistic serviceability c...

Finite Element Model Updating and Validation of the Uniovi Structure

The aim of this paper is the finite element modelling, updating and validation of the Uniovi Structure. This is a middle-size steel frame. The updating is based on natural frequencies, which are obtained from the free vibration of the structure. Three uncertain structural parameters are updated on the basis of the natural frequencies of two different configurations through an adaptive stochastic algorithm. Additional configurations corresponding to mass modifications were used to validate the updated model. It is found that the updated model can reproduce accurately the first two natural frequencies in all the configurations.

Nonlinear Modelling and Identification of a Small-Scale Bridge

The dynamic modelling and identification of a small-scale bridge is addressed in this paper. Two finite element models with linear elastic stiffness and different damping modelling has been tried. They correspond to a linear viscous damping and a nonlinear elasto-slip one. Both models were fitted to the available experimental data by a novel adaptive sampling technique that was repeated several times. In all the runs the technique yielded consistent results, which confirms its robustness. The elasto-slip model gave excellent fitting to the experimental data, while the results of the linear viscous one were poor.Copyright