Francesc Roure

Design of Steel Storage Rack Columns via the Direct Strength Method

AbstractThe paper presents an attempt to predict the load carrying capacity of perforated rack columns by the direct strength method (DSM). The investigation is focused on two different issues: the prediction of the elastic buckling loads of members with multiple perforations; and the evaluation of the accuracy of the current DSM buckling curves when applied to rack columns. In relation to the first issue, a model for the calculation of the reduced thickness of the perforated strip to be used in finite-strip buckling analysis is developed. Regarding the study of the DSM curves, it is demonstrated that they can be used to accurately determine the strength of rack cross sections whose failure is governed by distortional buckling or global buckling (with no significant participation of local buckling). This is an interesting result because it will allow substituting the distortional buckling tests, that are currently carried out in the process of design of these columns, by a simple and easy to apply calcula...

Computational modeling of electromechanical propagation in the helical ventricular anatomy of the heart

The classical interpretation of myocardial activation assumes that the myocardium is homogeneous and that the electrical propagation is radial. However, anatomical studies have described a layered anatomical structure resulting from a continuous anatomical helical disposition of the myocardial fibers. To further investigate the sequence of electromechanical propagation based on the helical architecture of the heart, a simplified computational model was designed. This model was then used to test four activation patterns, which were generated by propagating the action potential along the myocardial band from different activation sites.

Analysis of the Electro-Mechanical Activation Sequence of the Myocardium Following the Path Described by the HVMB

In order to contribute in the study of the HVMB, a computational model to simulate the behaviour of the myocardial tissue, mainly based in the fibre, is presented in a computational simplified model of the HVMB. The results obtained are compared with others works in the literature to conclude that if the electro-mechanical activation sequence in the myocardium coincides with the path described by the HVMB the path and the delay observed in the shortening of the fibres are according with the expected and observed behaviour in real hearts.

Computational Analysis of the Electro-Mechanical Activation Sequence of the Myocardium

In 1975 the valencian cardiologist F. Torrent-Guasp described the heart as a Helical Ventricular Myocardial Band (HVMB) in which “The ventricular myocardium is presented when it is unrolled under the form of a single big muscular band that, due to its special disposition, describes two cavities in the intact heart” [1]. It gives a different perspective of the morphology of the heart than the current and it could explain better and most coherently the propagation of the electrical stimulus which activates the shortening of the fibres, the complex deformation movement of the heart and maybe an explanation about understanding the cardiac contraction.Copyright