Abstract

The cardiovascular diseases constitute one of the main causes of death worldwide. One of the main diseases is atherosclerosis, which causes narrowing of the arterial lumen. In order to solve this condition, several treatments have been developed, and Percutaneous Transluminal Coronary Angioplasty (PTCA) with the placement of stent have gained relevancy. Many of these devices are currently coated to increase the biocompatibility and to decrease the restenosis risks. The biomechanical studies of the stent-coating interface behavior are necessary given the associated risks to possibility of failures or breakages of the coating during stent deployment. In this study the possible occurrence of coating delamination during stent deployment and the influence of parameters as the thickness and material were studied. The study starts by obtaining a geometric model of a stent unit of the Sirius Carbostent stent for the further processing by the Finite Element Method. The simulation was developed by applying restrictions so that the modeled stent hinge simulates his behavior during stent deployment. Considering these aspects it was possible to evaluation the coating integrity. With this model it was possible to predict the occurrence of delamination during stent deployment and to determine that the delamination risks increases with increasing the coating thickness. Finally, it was obtained a general function that allows to determine the maximal contact stress for a stent hinge with an U shape.

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Composite profiles processed by pultrusion are replacing metallic profiles in sectors like building or automotive, due to two interested properties: lightweight (the gas consumtion of the vehicle will be reduced) and corrosion resistance. However, if the profile needs to be covered in order to achieve aesthetic properties or new functionalities, several drawbacks arise (high labour content and VOCs and small particles emissions), limitating its competitivness versus profile metals. In this work the results of COALINE project are described; pultrusion process has been enhanced achieving a coated profile inside the mould (with a gelcoat or a primer) thanks to the development and integration of a sensor system (needed to adjust the curing degree of the resin in each stage of the process), a MW technology curing (to faster the curing time of the resin and shorten the lenght mould) and a modular advanced die design. Two moulds have been manufactured and a covered profiled obained in-line has been achieved for the building sector. For the automotive sector a case study cargo bed has been manufactured using profiles covered with the primer and joined with an adhesive with debonding capability to provide a simple repair or recycling at the end life-cycle.