Methodologies for teaching an engineering subject in different countries: comparison and results

Engineering or technical degrees are difficult to teach and, consequently, have always been characterized by a large number of academic failures. Therefore, continuous assessment has been applied to classes of similar content, related to Port and Coastal Engineering during these last years in three different Universities worldwide: University of La Republica (Montevideo, Uruguay), Nova de Lisboa (Portugal) and Cadiz (Spain). This paper presents different methodologies used to teach and evaluate these courses at each University, together with the results of the evaluations of the students who were enrolled during the current and previous stages. Generally, a decrease in the number of students who abandon the classes has been noticed together with an increase in the percentage of students who pass and an improvement of their grades, except at the University Nova de Lisboa were the results have remained stable. In addition, changes experienced in the courses are discussed herein by comparing the percentage of success in the different locations. Moreover, influence of the different methodologies and the possible reasons for these changes are also presented and analysed. As a conclusion, the improvement in educational outcomes has been achieved through the concurrence of different factors: the existence of more frequent written and/or oral exams, practical examples of case studies as well as access to specific tools of new technology and to documentation specifically prepared for the classes and available online. Evidently, the above mentioned tasks require a strong commitment and great effort by the teaching staff. If human resources diminish, as it is happening in Spain and Portugal due to the budget reduction in education, two difficult questions arise: For how long will teachers’ current effort be maintained? What impact will have their complete devotion to teaching in their research performance

Hysteretic Damping as an Energy Parameter in Gigacycle Fatigue

The mechanical behaviour of materials subjected to dynamic loading is now a classical subject but is still a big challenge. The fatigue limit of the materials, defined as the maximum dynamic load amplitude level for which no fatigue failures occur, has been set for a number of load cycles up to 10E7. Extending this limit with the traditional hardware is a much more difficult technical task due to the length of time needed for the completion of tests, but there is a real industrial concern about this subject due to the growing need to extend the lifecycle of some structures beyond such limits. Therefore, the study of fatigue is being extended to more than 10E7 cycles, typically 10E9 and more, in a new area of studies known as gigacycle fatigue. It is within this framework that the study presented in this paper fits. The approach here presented is based on the fact that the fatigue problem can be understood in terms of the energy available for irreversible process triggering. This energy will be involved in micro-structural irreversible changes in the material before being dissipated as thermal energy. The energy needed to trigger such changes must come from the dynamic loading. In fact, the balance between the energy supplied to and returned by the material is positive and the hysteretic damping factor represents the inelastic fraction of energy balance for each cycle.Final Accepted Versio

Harmonica: Stepped-Sine Spectrum Analyser for Transfer Function Measurement and Non-Linear Experimental Assessment

Non peer reviewe

Transmissibility matrix in harmonic and random processes

Abstract. The transmissibility concept may be generalized to multi-degree-of-freedom systems with multiple random excitations. This generalization involves the definition of a transmissibility matrix, relating two sets of responses when the structure is subjected to excitation at a given set of coordinates. Applying such a concept to an experimental example is the easiest way to validate this method

Ground penetrating radar investigations in the noble hall of São Carlos theater in Lisbon, Portugal

This paper describes a study conducted by the National Laboratory for Civil Engineering of Portugal (LNEC), in cooperation with the Defense University Center at the Spanish Naval Academy and “La Sapienza,” University of Rome, to assess the health and safety conditions of the Noble Hall floor in the São Carlos National Theater (Lisbon, Portugal). In a multidisciplinary approach, extensive fieldwork was carried out. The survey included the location and characterization of beams in the various areas of the floor by using two ground penetrating radar (GPR) systems equipped with two different ground- or air-coupled antennas, local inspection openings to visually assess the geometry, timber species and conservation state of structural members, and an assessment of the conservation state of the timber beam ends using drilling equipment. All the tests performed and the results obtained are presented. The potential of using non-destructive tests for the inspection of timber cultural heritage structures, particularly GPR, is discussed, and some practical recommendations are made

Using the Detection and Relative Damage Quantification Indicator (DRQ) with transmissibility

Copyright 2010 Elsevier B.V., All rights reserved.The Detection and Relative Damage Quantification Indicator (DRQ) was presented previously as a reliable damage detection indicator when used with Operational Deflection Shapes (ODS). The DRQ was computed from the Response Vector Assurance Criterion (RVAC) between the damaged and the initial ODS and the resulting value proved to be a good indicator of the presence of damage. The use of the ODS implies that the loads applied to the structure with and without damage are either known or, at least, the same. If the forces are not deterministic but still ergodic, the power spectrum could be used to evaluate the ODS, but still the above conditions hold, in a statistical sense. When a structure is subjected to ambient excitation, those conditions can hardly be assured. The loads may vary quite significantly and the ODS changes may be due to those changes instead of the presence of damage. To avoid this handicap, the authors explore here the use of the Transmissibility functions. If properly defined, the Transmissibility is invariant with respect to the amplitude of the loads. Since the Displacement Transmissibility is load invariant, a picked set of responses can be measured in service and used to predict another set; the result will then be correlated to the actual values using the RVAC and the DRQ will be computed. Numerical and experimental examples illustrate the proposed technique.Non peer reviewe

GPR monitoring for road transport infrastructure: a systematic review and machine learning insights

Xunta de Galicia | Ref. ED431F 2021/08Ministerio de Ciencia e Innovación | Ref. RYC2019-026604-

GPR monitoring for road transport infrastructure: a systematic review and machine learning insights

Suitable road pavements assessment becomes essential to provide safe traffic movements of people and goods. Moreover, a reliable transportation network is a crucial aspect of economic growth. Road pavements are subjected to various factors that influence overall performance (e.g., traffic load, temperature, moisture, delamination of the pavement layers, subsurface condition, etc.). These factors can reduce the infrastructure's life and decrease the circulation comfort of the vehicles in the transportation network. Early inspection of pavements optimizes maintenance and repairing methodologies, decreasing the maintenance cost and increasing the lifespan of the road pavements. Non-destructive techniques are strongly recommended to achieve accurate and valuable information from the subsurface condition. Ground Penetrating Radar (GPR) is a non-destructive geophysical method widely used on infrastructure assessment, particularly in road pavements, due to its low operation cost, time-saving, non-invasive, and less workforce. This paper presents a critical state of the art of applying GPR to diagnose road pavement and detect inner damages such as debonding, sinkholes, moisture, etc. The incorporation of the GPR with other complementary techniques in pavement inspection is also discussed. Through the review, the GPR capabilities for road inspection and evaluation of subsurface identification have been successfully demonstrated and validated in numerous studies and case studies. Finally, the application of more recent processing techniques to support decision-making owners/operators, such as machine learning and intelligent data analysis methods, and the future challenges on the GPR application in road pavements are introduced.- This project has received funding from the European Union's Hori-zon 2020 research and innovation program under grant agreements No. 769129 (PANOPTIS) and No. 955356 (HERON) . The project has also partially supported by the GAIN, Xunta de Galicia, through the project ENDITi (Ref. ED431F 2021/08) . Rasol M. acknowledges the financial support from Gustave Eiffel University, and Solla M. acknowledges the grant RYC2019-026604-I funded by MCIN/AEI/10.13039/501100011033 and by "ESF Investing in your future"