Guido De Roeck

Dynamic analysis of high speed railway bridge under articulated trains

Abstract The problem of vehicle–bridge dynamic interaction system under articulated high speed trains is studied in this paper. A dynamic interaction model of the bridge-articulated train system is established, which is composed of an articulated vehicle element model and a finite element bridge model. The vehicle model is established according to the structure and suspending properties of the articulated vehicles. A computer simulation program is worked out. As an example, the case of the Thalys articulated train passing along the Antoing Bridge on the Paris–Brussels high speed railway line is analyzed. The dynamic responses of the bridge and the vehicles are calculated. The proposed analysis model and the solution method are verified through the comparison between the calculated results and the in situ measured data. The vibration behaviour of the articulated trains is discussed.

Fuzzy Frequency Response Function of a Composite Floor Subject to Uncertainty by Application of the Gad Algorithm

During the last decade, the application of fuzzy numbers in the civil engineering domain has evolved from small academic applications to large scale industrial cases. The most popular algorithm to perform the involved fuzzy calculations is the Transformation Method [1], although the application area of this method is limited by the requirement of monotonic input-output relationships on the one hand, and by the number of uncertain variables on the other hand: in case of non-monotonic input-output relationships, the Transformation Method may lead to an underestimation of the uncertainty on response variables, and the computational cost increases exponentially with the number of uncertain variables.

SYNCHRONIZATION OF DATA ACQUISITION SYSTEMS FOR THE PURPOSE OF STRUCTURAL HEALTH MONITORING

This paper presents a technique for offline time synchronization of data acquisition systems for linear structures with proportional damping. The technique can be applied when direct synchronization of data acquisition systems is impossible or not sufficiently accurate, for example when multiple measurement nodes with different clock signals are embedded in a health monitoring network. The synchronization is based on the acquired dynamic response of the structure only, and does not require the acquisition of a shared sensor signal or a trigger signal. The time delay is identified from the spurious phase shift of the mode shape components that are obtained from system identification. A demonstration for a laboratory experiment on a cantilever steel beam shows that the proposed methodology can be used for accurate time synchronization, resulting in a significant improvement of the accuracy of the identified mode shapes. 2719 Available online at www.eccomasproceedia.org Eccomas Proceedia COMPDYN (2017) 2719-2728

SENSITIVITY ANALYSIS OF THE FREE WAVE CHARACTERISTICS OF PERIODIC STRUCTURES

The free wave characteristics, i.e. propagation constants and free waves, characterize the dynamic behaviour of periodic structures. For this reason, they may therefore provide a viable alternative to modal characteristics for finite element model updating. The sensitivities of the free wave characteristics to model parameters are required when using a gradient-based optimization algorithm for model updating. This paper investigates the sensitivity of the free wave characteristics to the model parameters. In this paper, an analytical expression of the sensitivities is derived and verified by comparison to results obtained by finite differences in a case study. The resulting sensitivities are compared to those of the modal characteristics to check their use in finite element model updating. In the case considered, the sensitivities of free wave characteristics are higher than those of the corresponding modal characteristics, indicating that free wave characteristics may be an alternative for model updating. 500 Available online at www.eccomasproceedia.org Eccomas Proceedia COMPDYN (2017) 500-508

Experimental failure analysis of shear-critical ordinary and steel-fibre prestressed concrete beams using optical measurement techniques

Although the use of fibre reinforced concrete (FRC) for structural applications is continuously increasing, it is still limited with respect to its potentials. This can be mainly attributed to the lack of international building codes for FRC structural elements. This paper aims to contribute to the development of suitable design principles for shear in FRC elements by presenting the preliminary results of 6 full-scale pretensioned steel-fibre reinforced concrete members. The main investigated parameters are the amount of prestressing, the amount of shear reinforcement and the fibre dosage respectively. All specimens are subjected to a four-point bending test until failure. Traditional mechanical measurement devices are used in combination with advanced optical measurement systems (i.e. stereo-vision digital image correlation 3D DIC and Bragg grated optical fibres). Apart from the full-scale tests, a number of small-scale experimental investigations are performed to characterize the material properties. The experimentally determined results are compared to predictions using analytical models found in Eurocode 2 (EC2) and Model Code 2010 (MC2010). Based on the obtained full-field data from the DIC systems and the detailed deformation information obtained from the Bragg grated optical fibres, an assessment is made of the mechanical behaviour.