http://hdl.handle.net/10256/17766 2025-08-13T04:59:10Z 2025-08-13T04:59:10Z Garulli, Torquato Arteiro, Albertino Blanco Villaverde, Norbert Renart Canalias, Jordi http://hdl.handle.net/10256/25101 2024-12-02T11:48:55Z 2024-07-01T00:00:00Z

Interlaminar fracture testing of multidirectional laminates: on finitewidth effect and residual stresses Garulli, Torquato; Arteiro, Albertino; Blanco Villaverde, Norbert; Renart Canalias, Jordi Fibre reinforced polymers, and in particular laminated plates, are widely used in structural applications. Interlaminar fracture (delamination) is a critical damage mechanism for these materials. Interlaminar fracture toughness is characterised using unidirectional specimens. While the toughness at interfaces in multidirectional laminates may be different, there is no consensus on how to effectively characterise it, due to a number of challenges associated with the use of multidirectional specimens. In this work, we review in detail some of these problems, namely, 3-dimensional effects and residual thermal stresses. We then present a strategy to design a set of Fully-Uncoupled Multidirectional specimens enabling a further understanding of these problems Conferència presentada en la "21st European Conference on Composite Materials (ECCM21)", celebrada a Nantes, França, del 2 al 5 de juliol de 2024 i organitzada cada dos anys pels membres de la Societat Europea de Materials Composites (ESCM)

2024-07-01T00:00:00Z Guerra Sánchez, Antonio Ciurana, Quim de http://hdl.handle.net/10256/17767 2024-12-04T13:00:20Z 2019-06-19T00:00:00Z

Stent Manufacturing Field: Past, Present, and Future Prospects Guerra Sánchez, Antonio; Ciurana, Quim de In medicine, cardiovascular problems, which result in heart failure, are a life-threatening sickness. Heart diseases include numerous problems, many of which are related to a process called atherosclerosis, a disease that narrows the vessel reducing the blood flow. Nowadays, angioplasty, also known as percutaneous coronary interventions (PCI), balloon angioplasty, and coronary artery balloon dilation, is a procedure where a special tubing (stent) is placed to open the narrowed arterial vessel. From the introduction of PCI, nobody was able to predict the advances that will occur in stent technology over the upcoming decades [1]. Since PCI appearances, it became evident that this approach has significant limitations, such as vessel occlusion and/or restenosis [2]. To overcome these problems, bare metal stents (BMS) were introduced, and despite reducing the vessel occlusion, however, high rates of restenosis constituted their major limitation [3]. To surmount this hurdle, the metallic stent coated with antiproliferative drug was conceived, the drug-eluting stents (DES). With the introduction of DES, the antiproliferative drug over the struts prolonged vessel wall healing, reduced neointima hyperplasia, and consequently decreased the target lesion revascularization (TLR). The most important limitation of the first generation of DES was related to the lack of biocompatibility of the drug-eluting polymer leading to a persistent inflammatory response after the drug-eluting period. Although permanent stents (BMS and DES) are effective, in most cases, the role of stent is temporary and is limited to the intervention, and shortly thereafter, until healing and re-endothelialization are obtained [4]. Bioresorbable stents (BRS) were introduced to overcome these limitations with important advantages: complete bioresorption, mechanical flexibility, etc. The BRS concept introduced the use of polymers in stenting procedures for the first time. With the inclusion of polymeric materials in the field of stents, a new and promising idea makes its way, electrospun tubular scaffolds (ETS) for stenting process. Unlike current stents, ETS theoretically could present some advances such as (I) better longitudinal flexibility to help the placement of the stent and (II) their surface mimics body tissue to help to obtain a best proliferation rates [5] and thus a rapid endothelialization. Nevertheless, ETS could have some disadvantages such as their radial flexibility. The radial expansion of ETS will occur by elongation of its fibers, in contrast to current stents in which it occurs by elongation of its radial cells. This fact could make correct vessel support difficult, which would restrict the use of ETS for only peripheral applications. With the author’s best knowledge, this new idea has been overlooked, but it presents a promising approach to solve cardiovascular problems. Stents can be used for a wide range of indication: de novo lesions, small vessel disease (SVD), bifurcation lesions, and tortuous and narrows lesions. Stents can improve the clinical outcomes for all of these indications as well as quality of life for patients suffering from this debilitating disease. In 2013, sales of DES and BMS in the 10 major markets were $ 4.89 billion. Global data [6] estimates that by 2020, sales of stents will grow to $ 5.65 billion

2019-06-19T00:00:00Z