ISEL - Instituto Superior de Engenharia de Lisboa
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Browsing ISEL - Instituto Superior de Engenharia de Lisboa by Author "Abdalla Filho, João Elias"
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- Dynamic calibration of slab track models for railway applications using full-scale testingPublication . Sainz-Aja, Jose Adolfo; Pombo, João; Tholken, D.; Carrascal, I.; Polanco, J.; Ferreno, D.; Casado, J.; Diego, S.; Perez, A.; Abdalla Filho, João Elias; Esen, A.; Čebašek, Tina Marolt; Laghrouche, Omar; Woodward, P.Research and development of technology for railways has found new impetus as society continues to search for cost effective and sustainable means of transport. This tasks engineers with using the state-of-the-art science and engineering for rolling stock development and advanced technologies for building high performance, reliable and cost-effective rail infrastructures. The main goal of this work is to develop detailed and validated three-dimensional slab track models using a finite element formulation, which include all components of the infrastructure. For this purpose, the parameters of the computational models are identified by performing full-scale tests of the fastening system and of the slab track, including all its material layers. The computational model proposed here is calibrated using this approach and a good agreement is obtained between experimental and numerical results. This work opens good perspectives to use this reliable track model to study the interaction with railway vehicles in realistic operation scenarios in order to assess the dynamic behaviour of the trains and to predict the long-term performance of the infrastructure and of its components.
- Three-dimensional modelling of slab-track systems based on dynamic experimental testsPublication . Thölken, D.; Abdalla Filho, João Elias; Pombo, João; Sainz-Aja, J.; Carrascal, I.; Polanco, J.; Esen, A.; Laghrouche, O.; Woodward, P.The accurate computational modelling of railway systems is crucial for analysis and design, which allows for excellent and enduring performance of such systems. It is capable of providing the industry with data for improving speed, comfort, load capacity and reliability. Further, as accurate solutions serve as an aid to improve railway systems, they contribute to quality services, social welfare, cost effectiveness and sustainability. An important component of a railway system is the track, which, in general, requires high investments for construction and maintenance. This work develops calibrated three-dimensional (3D) Finite Element (FE) models for slab track systems which can be employed for analysis and design with great level of reliability. These models are developed based on full-scale dynamic tests performed under the application of loads which simulate the passage of high-speed trains. The components considered are the rails, rail pads, slab track, grout, Hydraulicaly Bonded Layer (HBL), Frost Protection Layer (FPL) and subgrade. The FE models are built and calibrated in order to reproduce the measured displacement and acceleration test results. Due to the uncertainties in some material properties, a parametric analysis is also performed to establish to which material characteristics of the system the model is more sensitive to. It has been found that the Young’s moduli for the FPL layer and subgrade are the most important parameters. Further, the stiffness properties of rail pads play a paramount role in the accuracy of the model.
- Validated slab track models for railway vehicle dynamicsPublication . Thölken, Denise; Hou, Bowen; Esen, Ahmet; Marolt, Tina; Pombo, João; Meacc, Martina; Shi, Zhiyong; Meli, Enrico; Rindi, Andrea; Abdalla Filho, João Elias; Laghrouche, Omar; Woodward, PeterModern society demands and environmental factors are putting pressure in the development of new high speed rail networks or on the upgrade of conventional tracks to allow a significant increase in operational speeds and/or load capacity. Such requirements raise scientific and technological challenges that need to be addressed, which include the improvement of numerical tools and experimental techniques to support the design solutions. The dynamic analysis of railway systems involves multidisciplinary problems for which the most recente computer codes for rail applications only allow the study of a particular phenomenon at a time, each with its own mathematical model. By analysing such phenomena independently, it is not possible to capture all the dynamics of the complete railway system and the relevant coupling effects.