Some recent applications of non-linear models to the engineering practice

The Department of Structural Analysis of the University of Santander has been for a longtime involved in the solution of the country´s practical engineering problems. Some of these have required the use of non-conventional methods of analysis, in order to achieve adequate engineering answers. As an example of the increasing application of non-linear computer codes in the nowadays engineering practice, some cases will be briefly presented. In each case, only the main features of the problem involved and the solution used to solve it will be shown

Multidisciplinary Learning, Another way of Teaching Maths in Engineering

Multidisciplinary training is widely appreciated in industry and business, and nevertheless usually is not addressed in the early stages of most undergraduate programs. We outline here a multidisciplinary course for undergraduates studying engineering in which mathematics would be the common language, the transverse tool. The goal is motivating students to learn more mathematics and as a result, improve the quality of engineering education. The course would be structured around projects in four branches in engineering: mechanical, electrical, civil and bio-tech. The projects would be chosen among a wide variety of topics in engineering practice selected with the guidance of professional engineers. In these projects mathematics should interact with at least two other basic areas of knowledge in engineering: chemistry, computers science, economics, design or physics.

Generic competences in engineering field: a comparative study between Latin America and European Union

In this work, a comparison between the competences codes in the CDIÓs* curriculum, the ones defined for the Tunning Project and the International Project Management Association (IPMA) is made. The goal is to define the most appropriate competences codes for the engineering education in Latin America. The CDIO code is obtained from the engineering practice, and responds to the Accreditation Board for Engineering and Technology (ABET) standards of accreditation. The Tuning competences are the ones defined for Latin America and the IPMÁs are international competences for project management. It is the first time that the competences defined in ABET accreditation standards in the engineering field are compared with the international competences according to IPMÁs model. The results give evidence that, in first place, there is a need to apply holistic models in the definition of an engineering curriculum. Second, the pertinence of these models in the definition of engineering programs in Latin America.

Enhancing skills in solving open-ended problems using game-based exercises

Some requirements for engineering programmes, such as an ability to use the techniques, skills and modern engineering tools necessary for engineering practice, as well as an understanding of professional and ethical responsibility or an ability to communicate effectively, need new activities designed for measuring students’ progress. Negotiations take place continuously at any stage of a project and, so, the ability of engineers and managers to effectively carry out a negotiation is crucial for the success or failure of projects and businesses. Since it involves communication between individuals motivated to come together in an agreement for mutual benefit, it can be used to enhance these personal abilities. The main objective of this study was to evaluate the adequacy of mixing playing sessions and theory to maximise the students’ strategic vision in combination with negotiating skills. Results show that the combination of playing with theoretical training teaches students to strategise through analysis and discussion of alternatives. The outcome is then more optimised.

Preface : (Boundary Element Method) Computers and Structures 83 (2005)

The Boundary Element Method is a powerful numerical technique well rooted in everyday engineering practice. This is shown by boundary element methods included in the most important commercial computer packages and in the continuous publication of books composed to explain the features of the method to beginners or practicing engineers. Our first paper in Computers & Structures on Boundary Elements was published in 1979 (C & S 10, pp. 351–362), so this Special Issue is for us not only the accomplishment of our obligation to show other colleagues the possibilities of a numerical technique in which we believe, but also the celebration of our particular silver jubilee with this Journal.

Impedance of foundations using the Boundary Integral Equation Method

Dynamic soil-structure interaction has been for a long time one of the most fascinating areas for the engineering profession. The building of large alternating machines and their effects on surrounding structures as well as on their own functional behavior, provided the initial impetus; a large amount of experimental research was done,and the results of the Russian and German groups were especially worthwhile. Analytical results by Reissner and Sehkter were reexamined by Quinlan, Sung, et. al., and finally Veletsos presented the first set of reliable results. Since then, the modeling of the homogeneous, elastic halfspace as a equivalent set of springs and dashpots has become an everyday tool in soil engineering practice, especially after the appearance of the fast Fourier transportation algorithm, which makes possible the treatment of the frequency-dependent characteristics of the equivalent elements in a unified fashion with the general method of analysis of the structure. Extensions to the viscoelastic case, as well as to embedded foundations and complicated geometries, have been presented by various authors. In general, they used the finite element method with the well known problems of geometric truncations and the subsequent use of absorbing boundaries. The properties of boundary integral equation methods are, in our opinion, specially well suited to this problem, and several of the previous results have confirmed our opinion. In what follows we present the general features related to steady-state elastodynamics and a series of results showing the splendid results that the BIEM provided. Especially interesting are the outputs obtained through the use of the so-called singular elements, whose description is incorporated at the end of the paper. The reduction in time spent by the computer and the small number of elements needed to simulate realistically the global properties of the halfspace make this procedure one of the most interesting applications of the BIEM.

Crack width control in RC elements with recycled steel fibres and applications to integral structures : theoretical and experimental study

El presente trabajo trata de elementos reforzados con barras de armadura y Fibras Metálicas Recicladas (FMR). El objetivo principal es mejorar el comportamiento a fisuración de elementos sometidos a flexión pura y a flexión compuesta, aumentando en consecuencia las prestaciones en servicio de aquellas estructuras con requerimientos estrictos con respecto al control de fisuración. Entre éstas últimas se encuentran las estructuras integrales, es decir aquellas estructuras sin juntas (puentes o edificios), sometidas a cargas gravitatorias y deformaciones impuestas en los elementos horizontales debidas a retracción, fluencia y temperatura. Las FMR son obtenidas a partir de los neumáticos fuera de uso, y puesto que el procedimiento de reciclado se centra en el caucho en vez que en el acero, su forma es aleatoria y con longitud variable. A pesar de que la eficacia del fibrorefuerzo mediante FMR ha sido demostrada en investigaciones anteriores, la innovación que representa este trabajo consiste en proponer la acción combinada de barras convencionales y FMR en la mejora del comportamiento a fisuración. El objetivo es por tanto mejorar la sostenibilidad del proyecto de la estructura en HA al utilizar materiales reciclados por un lado, y aumentando por el otro la durabilidad. En primer lugar, se presenta el estado del arte con respecto a la fisuración en elementos de HA, que sucesivamente se amplía a elementos reforzados con barras y fibras. Asimismo, se resume el método simplificado para el análisis de columnas de estructuras sin juntas ya propuesto por Pérez et al., con particular énfasis en aquellos aspectos que son incompatibles con la acción de las fibras a nivel seccional. A continuación, se presenta un modelo para describir la deformabilidad seccional y la fisuración en elementos en HA, que luego se amplía a aquellos elementos reforzados con barras y fibras, teniendo en cuenta también los efectos debidos a la retracción (tension stiffening negativo). El modelo es luego empleado para ampliar el método simplificado para el análisis de columnas. La aportación consiste por tanto en contar con una metodología amplia de análisis para este tipo de elementos. Seguidamente, se presenta la campaña experimental preliminar que ha involucrado vigas a escala reducida sometidas a flexión simple, con el objetivo de validar la eficiencia y la usabilidad en el hormigón de las FMR de dos diferentes tipos, y su comportamiento con respecto a fibras de acero comerciales. Se describe a continuación la campaña principal, consistente en ensayos sobre ocho vigas en flexión simple a escala 1:1 (variando contenido en FRM, Ø/s,eff y recubrimiento) y doce columnas a flexión compuesta (variando contenido en FMR, Ø/s,eff y nivel de fuerza axil). Los resultados obtenidos en la campaña principal son presentados y comentados, resaltando las mejoras obtenidas en el comportamiento a fisuración de las vigas y columnas, y la rigidez estructural de las columnas. Estos resultados se comparan con las predicciones del modelo propuesto. Los principales parámetros estudiados para describir la fisuración y el comportamiento seccional de las vigas son: la separación entre fisuras, el alargamiento medio de las armaduras y la abertura de fisura, mientras que en los ensayos de las columnas se ha contrastado las leyes momento/curvatura, la tensión en las barras de armadura y la abertura de fisura en el empotramiento en la base. La comparación muestra un buen acuerdo entre las predicciones y los resultados experimentales. Asimismo, se nota la mejora en el comportamiento a fisuración debido a la incorporación de FMR en aquellos elementos con cuantías de armadura bajas en flexión simple, en elementos con axiles bajos y para el control de la fisuración en elementos con grandes recubrimientos, siendo por tanto resultados de inmediato impacto en la práctica ingenieril (diseño de losas, tanques, estructuras integrales, etc.). VIIIComo punto final, se presentan aplicaciones de las FMR en estructuras reales. Se discuten dos casos de elementos sometidos a flexión pura, en particular una viga simplemente apoyada y un tanque para el tratamiento de agua. En ambos casos la adicción de FMR al hormigón lleva a mejoras en el comportamiento a fisuración. Luego, utilizando el método simplificado para el análisis en servicio de columnas de estructuras sin juntas, se calcula la máxima longitud admisible en casos típicos de puentes y edificación. En particular, se demuestra que las limitaciones de la práctica ingenieril actual (sobre todo en edificación) pueden ser aumentadas considerando el comportamiento real de las columnas en HA. Finalmente, los mismos casos son modificados para considerar el uso de MFR, y se presentan las mejoras tanto en la máxima longitud admisible como en la abertura de fisura para una longitud y deformación impuesta. This work deals with elements reinforced with both rebars and Recycled Steel Fibres (RSFs). Its main objective is to improve cracking behaviour of elements subjected to pure bending and bending and axial force, resulting in better serviceability conditions for these structures demanding keen crack width control. Among these structures a particularly interesting type are the so-called integral structures, i.e. long jointless structures (bridges and buildings) subjected to gravitational loads and imposed deformations due to shrinkage, creep and temperature. RSFs are obtained from End of Life Tyres, and due to the recycling process that is focused on the rubber rather than on the steel they come out crooked and with variable length. Although the effectiveness of RSFs had already been proven by previous research, the innovation of this work consists in the proposing the combined action of conventional rebars and RSFs to improve cracking behaviour. Therefore, the objective is to improve the sustainability of RC structures by, on the one hand, using recycled materials, and on the other improving their durability. A state of the art on cracking in RC elements is firstly drawn. It is then expanded to elements reinforced with both rebars and fibres (R/FRC elements). Finally, the simplified method for analysis of columns of long jointless structures already proposed by Pérez et al. is resumed, with a special focus on the points that conflict when taking into account the action of fibres. Afterwards, a model to describe sectional deformability and cracking of R/FRC elements is presented, taking also into account the effect of shrinkage (negative tension stiffening). The model is then used to implement the simplified method for columns. The novelty represented by this is that a comprehensive methodology to analyse this type of elements is presented. A preliminary experimental campaign consisting in small beams subjected to pure bending is described, with the objective of validating the effectiveness and usability in concrete of RSFs of two different types, and their behaviour when compared with commercial steel fibres. With the results and lessons learnt from this campaign in mind, the main experimental campaign is then described, consisting in cracking tests of eight unscaled beams in pure bending (varying RSF content, Ø/s,eff and concrete cover) and twelve columns subjected to imposed displacement and axial force (varying RSF content, Ø/s,eff and squashing load ratio). The results obtained from the main campaign are presented and discussed, with particular focus on the improvement in cracking behaviour for the beams and columns, and structural stiffness for the columns. They are then compared with the proposed model. The main parameters studied to describe cracking and sectional behaviours of the beam tests are crack spacing, mean steel strain and crack width, while for the column tests these were moment/curvature, stress in rebars and crack with at column embedment. The comparison showed satisfactory agreement between experimental results and model predictions. Moreover, it is pointed out the improvement in cracking behaviour due to the addition of RSF for elements with low reinforcement ratios, elements with low squashing load ratios and for crack width control of elements with large concrete covers, thus representing results with a immediate impact in engineering practice (slab design, tanks, integral structures, etc.). Applications of RSF to actual structures are finally presented. Two cases of elements in pure bending are presented, namely a simple supported beam and a water treatment tank. In both cases the addition of RSF to concrete leads to improvements in cracking behaviour. Then, using the simplified model for the serviceability analysis of columns of jointless structures, the maximum achievable jointless length of typical cases of a bridge and building is obtained. In XIIparticular, it is shown how the limitations of current engineering practice (this is especially the case of buildings) can be increased by considering the actual behaviour of RC supports. Then, the same cases are modified considering the use of RSF, and the improvements both in maximum achievable length and in crack width for a given length and imposed strain at the deck/first floor are shown.

Level 2 reliability of simplified pushover methods

Pushover methods are being used as an everyday tool in engineering practice and some of them have been included in Regulatory Codes. Recently several efforts have been done trying to look at them from a probabilistic viewpoint. In this paper the authors shall present a Level 2 approach based on a probabilistic definition of the characteristic points defining the response spectra as well as a probabilistic definition of the elasto-plastic pushover curve representing the structural behavior. Comparisons with Montecarlo simulations will help to precise the accuracy of the proposed approach.

The development of a wind tunnel DAQ system by using Labview tools

This paper presents the experimental three-year learning activity developed by a group of teachers in a wind tunnel facility. The authors, leading a team of students, carried out a project consisting of the design, assembly and testing of a wind tunnel. The project included all stages of the process from its initial specifications to its final quality flow assessments, going through the calculation of each element, and the building of the whole wind tunnel. The group of (final year) students was responsible for the whole wind tunnel project as a part of their bachelor degree project. The paper focuses on the development of wind tunnel data acquisition software. This automatic tool is essential to improve the automation of the data acquisition of the wind tunnel facility systems, in particular for a 6DOF multi-axis force/torque sensor. This work can be considered as a typical example of real engineering practice: a set of specifications that has to be modified due to the constraints imposed throughout the project, in order to obtain the final result

Migration to an a on-line laboatory in mechanical engineering. The case of a cam-follower design practice.

The European Higher Education Area (EHEA) has leaded to a change in the way the subjects are taught. One of the more important aspects of the EHEA is to support the autonomous study of the students. Taking into account this new approach, the virtual laboratory of the subject Mechanisms of the Aeronautical studies at the Technical University of Madrid is being migrated to an on-line scheme. This virtual laboratory consist on two practices: the design of cam-follower mechanisms and the design of trains of gears. Both practices are software applications that, in the current situation, need to be installed on each computer and the students carry out the practice at the computer classroom of the school under the supervision of a teacher. During this year the design of cam-follower mechanisms practice has been moved to a web application using Java and the Google Development Toolkit. In this practice the students has to design and study the running of a cam to perform a specific displacement diagram with a selected follower taking into account that the mechanism must be able to work properly at high speed regime. The practice has maintained its objectives in the new platform but to take advantage of the new methodology and try to avoid the inconveniences that the previous version had shown. Once the new practice has been ready, a pilot study has been carried out to compare both approaches: on-line and in-lab. This paper shows the adaptation of the cam and follower practice to an on-line methodology. Both practices are described and the changes that has been done to the initial one are shown. They are compared and the weak and strong points of each one are analyzed. Finally we explain the pilot study carried out, the students impression and the results obtained.

Migration to an a on.line laboratory in mechanical engineering. The case of a cam follower design practice.

The European Higher Education Area (EHEA) has leaded to a change in the way the subjects are taught. One of the more important aspects of the EHEA is to support the autonomous study of the students. Taking into account this new approach, the virtual laboratory of the subject Mechanisms of the Aeronautical studies at the Technical University of Madrid is being migrated to an on-line scheme. This virtual laboratory consist on two practices: the design of cam-follower mechanisms and the design of trains of gears. Both practices are software applications that, in the current situation, need to be installed on each computer and the students carry out the practice at the computer classroom of the school under the supervision of a teacher. During this year the design of cam-follower mechanisms practice has been moved to a web application using Java and the Google Development Toolkit. In this practice the students has to design and study the running of a cam to perform a specific displacement diagram with a selected follower taking into account that the mechanism must be able to work properly at high speed regime. The practice has maintained its objectives in the new platform but to take advantage of the new methodology and try to avoid the inconveniences that the previous version had shown. Once the new practice has been ready, a pilot study has been carried out to compare both approaches: on-line and in-lab. This paper shows the adaptation of the cam and follower practice to an on-line methodology. Both practices are described and the changes that has been done to the initial one are shown. They are compared and the weak and strong points of each one are analyzed. Finally we explain the pilot study carried out, the students impression and the results obtained.

Tailoring the Scrum Development Process to Address Agile Product Line Engineering

Software Product Line Engineering (SPLE) is becoming widely used due to the improvement it means when developing software products of the same family. However, SPLE demands long-term investment on a product-line platform that might not be profitable due to rapid changing business settings. Since Agile Software Development (ASD) approaches are being successfully applied in volatile markets, several companies have suggested the idea of integrating SPLE and ASD when a family product has to be developed. Agile Product Line Engineering (APLE) advocates the integration of SPLE and ASD to address their lacks when they are individually applied to software development. A previous literature re-view of experiences and practices on APLE revealed important challenges about how to fully put APLE into practice. Our contribution address several of these challenges by tailoring the agile method Scrum by means of three concepts that we have defined: plastic partial components, working PL-architectures, and reactive reuse.

The Learning of the Mathematical Models to Aid Decision Making in the High Level Engineering Schools?

At present, in the University curricula in most countries, the decision theory and the mathematical models to aid decision making is not included, as in the graduate program like in Doctored and Master´s programs. In the Technical School of High Level Agronomic Engineers of the Technical University of Madrid (ETSIA-UPM), the need to offer to the future engineers training in a subject that could help them to take decisions in their profession was felt. Along the life, they will have to take a lot of decisions. Ones, will be important and others no. In the personal level, they will have to take several very important decisions, like the election of a career, professional work, or a couple, but in the professional field, the decision making is the main role of the Managers, Politicians and Leaders. They should be decision makers and will be paid for it. Therefore, nobody can understand that such a professional that is called to practice management responsibilities in the companies, does not take training in such an important matter. For it, in the year 2000, it was requested to the University Board to introduce in the curricula an optional qualified subject of the second cycle with 4,5 credits titled " Mathematical Methods for Making Decisions ". A program was elaborated, the didactic material prepared and programs as Maple, Lingo, Math Cad, etc. installed in several IT classrooms, where the course will be taught. In the course 2000-2001 this subject was offered with a great acceptance that exceeded the forecasts of capacity and had to be prepared more classrooms. This course in graduate program took place in the Department of Applied Mathematics to the Agronomic Engineering, as an extension of the credits dedicated to Mathematics in the career of Engineering.

Survey on integration of Applied Geology and Geomorphology in Civil Engineering curricula in the framework of the European Higher Education Area (EHEA) by using practical trips

The engineer must have sufficient theoretical knowledge to be applied to solve specific problems, with the necessary capacity to simplify these approaches, and taking into account factors such as speed, simplicity, quality and economy. In Geology, its ultimate goal is the exploration of the history of the geological events through observation, deduction, reasoning and, in exceptional cases by the direct underground exploration or experimentation. Experimentation is very limited in Geology. Reproduction laboratory of certain phenomena or geological processes is difficult because both time and space become a large scale. For this reason, some Earth Sciences are in a nearly descriptive stage whereas others closest to the experimental, Geophysics and Geochemistry, have assimilated progress experienced by the physics and chemistry. Thus, Anglo-Saxon countries clearly separate Engineering Geology from Geological Engineering, i.e. Applied Geology to the Geological Engineering concepts. Although there is a big professional overlap, the first one corresponds to scientific approach, while the last one corresponds to a technological one. Applied Geology to Engineering could be defined as the Science and Applied Geology to the design, construction and performance of engineering infrastructures in and field geology discipline. There has been much discussion on the primacy of theory over practice. Today prevails the exaggeration of practice, but you get good workers and routine and mediocre teachers. This idea forgets too that teaching problem is a problem of right balance. The approach of the action lines on the European Higher Education Area (EHEA) framework provides for such balance. Applied Geology subject represents the first real contact with the physical environment with the practice profession and works. Besides, the situation of the topic in the first trace of Study Plans for many students implies the link to other subjects and topics of the career (tunnels, dams, groundwater, roads, etc). This work analyses in depth the justification of such practical trips. It shows the criteria and methods of planning and the result which manifests itself in pupils. Once practical trips experience developed, the objective work tries to know about results and changes on student’s motivation in learning perspective. This is done regardless of the outcome of their knowledge achievements assessed properly and they are not subject to such work. For this objective, it has been designed a survey about their motivation before and after trip. Survey was made by the Unidad Docente de Geología Aplicada of the Departamento de Ingeniería y Morfología del Terreno (Escuela Técnica Superior de Ingenieros de Caminos, Canales y Puertos, Universidad Politécnica de Madrid). It was completely anonymous. Its objective was to collect the opinion of the student as a key agent of learning and teaching of the subject. All the work takes place under new teaching/learning criteria approach at the European framework in Higher Education. The results are exceptionally good with 90% of student’s participation and with very high scores in a number of questions as the itineraries, teachers and visited places (range of 4.5 to 4.2 in a 5 points scale). The majority of students are very satisfied (average of 4.5 in a 5 points scale).

Training organization of a middle-size company engaged in information technology services: theory and practice

In order to establish an active internal know-how -reserve~ in an information processing and engineering services . company, a training architecture tailored to the company as an whole must be defined. When a company' s earnings come from . advisory services dynamically structured i.n the form of projects, as is the case at hand, difficulties arise that must be taken into account in the architectural design. The first difficulties are of a psychological nature and the design method proposed here begjns wi th the definition of the highest training metasystem, which is aimed at making adjustments for the variety of perceptions of the company's human components, before the architecture can be designed. This approach may be considered as an application of the cybernetic Law of Requisita Variety (Ashby) and of the Principle of Conceptual Integrity (Brooks) . Also included is a description of sorne of the results of the first steps of metasystems at the level of company organization.