R. Gutiérrez

Numerical characterization of the structural behaviour of the Basilica of Pilar in Zaragoza (Spain). Part 2: Constructive process effects

In the first part of this article, the finite element models developed for the Basilica of Pilar have been described, as well as the results obtained in linear theory and considering the material non-linearity. In the second part, a study concerning the constructive process and the geometrical non-linearity on the previous models is developed. Firstly we consider the procedure to include various construction stages in the finite element formulation of a structural problem. Then a geometrical non-linear analysis is applied to the two global models of the temple, the historical model of 1927 state and the actual state model, comparing the results obtained with the linear ones and explaining the problems encountered. Afterwards, a hypothetical constructive process is applied to the global models by means of the geometrical non-linearity, verifying and explaining the importance of this type of analyses in the obtained numerical results, especially in the Regina Martirum dome. Finally, applying the non-linear staged construction, the effects of an excavation ditch made in 1996 on the temple are considered.

Real-Time MBS Formulations: Towards Virtual Engineering

This paper presents the research conducted during the last years by the Laboratory of Mechanical Engineering on real-time formulations for the dynamics of multi-body systems, a topic of great relevance for the development of new virtual reality applications. The work carried out by our group has been focused on: a) the development of real-time formulations capable of performing very fast calculations of the dynamics of complex rigid-flexible multi-body systems; b) the experimental validation of the motions, deformations and forces obtained through the application of the above-mentioned formulations, so as to verify that reality is being reasonably well imitated; c) the study of the aptitude of such formulations for becoming part of a virtual reality environment, in connection with user-interface devices. In the paper, a real-time formulation developed by the authors is described, along with some examples of rigid-flexible multi-body systems simulated with such formulation. Moreover, results of the experimental validation of one of the examples are shown. Finally, a simulator based on the proposed formulation is presented.

Benchmarking of MBS Simulation Software

Despite the importance given to the computational efficiency of multibody system (MBS) simulation tools, there is a lack of standard benchmarks to measure the performance of these kinds of software applications. Benchmarking is done on an individual basis: different sets of problems are used, and the procedures and conditions considered to measure computational efficiency are also different. In this scenario, it becomes almost impossible to compare the performance of the different available simulation methods in an objective and quantitative way. This works proposes a benchmarking system for MBS simulation tools. The system is made up by two components: (a) a collection of test problems with reference solutions and standardized procedures to measure computational efficiency; and (b) a web-based application to collect, organize and share information about performance of existing simulation methods. The benchmarking system has been applied to evaluate the performance of ADAMS/Solver, a popular MBS simulation tool.Copyright