Papers by Anders Rønnquist
Journal of Structural Engineering-asce, Sep 1, 2023
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Engineering Structures, May 1, 2023
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Journal of building engineering, Aug 1, 2023
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Report, 2019
Digital workflows are already widely used by the designers (architects and engineers) in creating... more Digital workflows are already widely used by the designers (architects and engineers) in creating a better Building Information Modelling (BIM) data flow. In the core of this design method is a para- metric model, which thanks to open source software can be easily customized according to the pro- ject or user needs. Shell or gridshell structures are very sensitive on the external loads, due to the low weight and big span. The accuracy and reliability are therefore a crucial point in design. More and more architects are using parametrical models, based on visual programing (like Grasshopper or Dynamo) to develop form of spatial structure. The parametric model in shell design gives a high precision in creating BIM model and is the starting point for the structural analysis. In this paper we will present a design method, in which the parametric model is not only the starting point for struc- tural analysis. Thanks to a well-established digital workflow it can occur, that structural analysis is made simultaneously with architectural form finding of the shell. The digital workflow, developed by our research group is based on the Finite Element Method (FEM). The design methodology is to create two kind of structural analyses. The first one, called global, is using beam elements to inves- tigate the general forces and deformations. The second one, called local, is using solid/volume ele- ments to investigate the connection solution. Thanks to fast information transfer between this two analysis and automation of this process, the architect can achieve information about feasibility of the whole designed structure in real time. To validate our approach the timber gridshell was de- signed. The structure with nontrivial shape and customized each of the 61 nodes, was build in 2016 in Trondheim. The nodes were manufactured with usage of the 3D printing technology.
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WIT Transactions on the Built Environment, Sep 1, 2005
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Springer eBooks, 2015
The Hardanger Bridge is the longest suspension Bridge in Norway and among the top 10 longest susp... more The Hardanger Bridge is the longest suspension Bridge in Norway and among the top 10 longest suspension bridges in the world. A comprehensive monitoring system was installed after it was completed in August 2013. The monitoring system is designed to provide data that can be used to verify the numerical methods used to predict wind induced dynamic response of slender bridges located in complex terrain. The monitoring system is outlined in this paper together with preliminary analysis of the accuracy of the model used to describe the self-excited forces acting on the bridge deck. Extensive wind tunnel testing was performed in the design of the Hardanger Bridge to achieve an excellent aerodynamic behaviour of the cross-section of the bridge deck. The experimental results of the aerodynamic derivatives that describe the self-excited forces have been combined with a finite element model of the bridge to predict the in-wind natural frequencies and damping ratios of the combined structure and flow system. The numerical predictions have been compared to results obtained from measured data using data-driven and covariance-driven stochastic subspace identification. It is concluded that the model for the self-excited forces provides in-wind frequencies and damping ratios that corresponds well to the observations from measured data.
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Proceedings of the Third International Conference on Railway Technology: Research, Development and Maintenance, Mar 10, 2016
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Wood Material Science and Engineering, Apr 19, 2023
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Mechanism and Machine Theory, Sep 1, 2023
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Journal of Wind Engineering and Industrial Aerodynamics, Dec 1, 2010
... by using indicial functions ([Borri et al., 2002] and [Scanlan et al., 1974]) or rational fun... more ... by using indicial functions ([Borri et al., 2002] and [Scanlan et al., 1974]) or rational functions ([Chen et al., 2000] and [Chen and Kareem, 2001 ... eg, [Chen et al., 2000], [Jain et al., 1996a] and [Katsuchi et al., 1998]) along with notable textbooks ([Dyrbye and Hansen, 1997], [Simiu ...
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IEEE Transactions on Instrumentation and Measurement, 2020
In high-speed rail operations, contact wire irregularity (CWI) in a catenary is a common disturba... more In high-speed rail operations, contact wire irregularity (CWI) in a catenary is a common disturbance to the pantograph–catenary interaction performance, which directly affects the quality of current collection. To describe the pointwise stochastics of CWI, the power spectral density (PSD) function for CWI is proposed, and its effect on the pantograph–catenary interaction is investigated. First, a preprocessing procedure is proposed to eliminate the redundant information in the measured irregularities based on the ensemble empirical mode decomposition (EEMD). Then, the upper envelope of the irregularity, which contains all the information regarding the dropper positions on the contact wire, is extracted. A form of the PSD function is suggested for contact wire irregularities. A methodology is proposed to include the effect of random irregularities in the assessment of the interaction performance of a pantograph–catenary. A developed target configuration under dead load (TCUD) method is used to calculate the initial configuration of the catenary, in which the dropper points on the contact wire are placed on their exact positions. Finally, the effect of the random contact wire irregularities on the contact force is investigated through 500 numerical simulations at each operating speed. The present results indicate that random irregularities have a direct impact on the pantograph–catenary contact, including an increment in the dispersion of the contact force statistics. The stochastic analysis shows that over 70% of the results with irregularities are worse than the ideal result without irregularities.
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Structure and Infrastructure Engineering, Nov 14, 2022
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Conference proceedings of the Society for Experimental Mechanics, 2016
Riveted steel bridges are common in the Norwegian and European railway network. Assessment of the... more Riveted steel bridges are common in the Norwegian and European railway network. Assessment of the current state is important to ensure continuous and safe operation of the railway. Furthermore, the prediction of remaining service life of these bridges is essential to allocate limited funds and resources to the most critical points in the infrastructure. Reliable and accurate numerical models are necessary tools to assess the current state and predict the remaining service life of these bridges.This paper presents work carried out in obtaining a validated finite element model of the Lerelva railway bridge. System identification was carried out with data driven stochastic subspace identification using data with both initial conditions from train passage and ambient excitation. The modal data from the system identification procedure was utilized in updating the finite element model.
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Structural Health Monitoring-an International Journal, May 20, 2022
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Papers by Anders Rønnquist