Examinando por Materia "tension"
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Ítem Designed for resistance to puncture: The dynamic response of fish scales(ELSEVIER SCIENCE BV, 2019-01-01) Ghods S.; Murcia S.; Ossa E.A.; Arola D.; Ghods S.; Murcia S.; Ossa E.A.; Arola D.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de IngenieríaNatural dermal armors are serving as a source of inspiration in the pursuit of “next-generation” structural materials. Although the dynamic strain response of these materials is arguably the most relevant to their performance as armors, limited work has been performed in this area. Here, uniaxial tension and transverse puncture tests were performed on specimens obtained from the scales of Asian carp over strain rates spanning seven decades, from 10-4 to 103 s-1. The importance of anatomical variations was explored by comparing the performance of scales from the head, middle and tail regions. In both loading orientations, the scales exhibited a significant increase in the resistance to failure with loading rate. The rate sensitivity was substantially higher for transverse loading than for in-plane tension, with average strain rate sensitivity exponents for measures of the toughness of 0.35 and 0.08, respectively. Spatial variations in the properties were largest in the puncture responses, and scales from the head region exhibited the greatest resistance to puncture overall. The results suggest that the layered microstructure of fish scales is most effective at resisting puncture, rather than in-plane tension, and its effectiveness increases with rate of loading. X-ray microCT showed that delamination of plies in the internal elasmodine and stretching of the fibrils were key mechanisms of energy dissipation in response to puncture loading. Understanding contributions from the microstructure to this behavior could guide the development of flexible engineered laminates for penetration resistance and other related applications. © 2018 Elsevier LtdÍtem In vitro mechanical evaluation of mandibular bone transport devices(ASME, 2014-06-01) Zapata, Uriel; Watanabe, Ikuya; Opperman, Lynne A.; Dechow, Paul C.; Mulone, Timothy; Elsalanty, Mohammed E.; Zapata, Uriel; Watanabe, Ikuya; Opperman, Lynne A.; Dechow, Paul C.; Mulone, Timothy; Elsalanty, Mohammed E.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de IngenieríaBone transport distraction osteogenesis (BTDO) is a surgical procedure that has been used over the last 30 years for the correction of segmental defects produced mainly by trauma and oncological resections. Application of BTDO has several clinical advantages over traditional surgical techniques. Over the past few years, several BTDO devices have been introduced to reconstruct mandibular bone defects. Based on the location and outline of the defect, each device requires a uniquely shaped reconstruction plate. To date, no biomechanical evaluations of mandibular BTDO devices have been reported in the literature. The present study evaluated the mechanical behavior of three different shaped prototypes of a novel mandibular bone transport reconstruction plate and its transport unit for the reconstruction of segmental bone defects of the mandible by using numerical models complemented with mechanical laboratory tests to characterize strength, fatigue, and stability. The strength test evaluated device failures under extreme loads and was complemented with optimization procedures to improve the biomechanical behavior of the devices. The responses of the prototypes were characterized to improve their design and identify weak and strong regions in order to avoid posterior device failure in clinical applications. Combinations of the numerical and mechanical laboratory results were used to compare and validate the models. In addition, the results remark the importance of reducing the number of animals used in experimental tests by increasing computational and in vitro trials. © VC 2014 by ASME.Ítem In vitro mechanical evaluation of mandibular bone transport devices(ASME, 2014-06-01) Zapata, Uriel; Watanabe, Ikuya; Opperman, Lynne A.; Dechow, Paul C.; Mulone, Timothy; Elsalanty, Mohammed E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)Bone transport distraction osteogenesis (BTDO) is a surgical procedure that has been used over the last 30 years for the correction of segmental defects produced mainly by trauma and oncological resections. Application of BTDO has several clinical advantages over traditional surgical techniques. Over the past few years, several BTDO devices have been introduced to reconstruct mandibular bone defects. Based on the location and outline of the defect, each device requires a uniquely shaped reconstruction plate. To date, no biomechanical evaluations of mandibular BTDO devices have been reported in the literature. The present study evaluated the mechanical behavior of three different shaped prototypes of a novel mandibular bone transport reconstruction plate and its transport unit for the reconstruction of segmental bone defects of the mandible by using numerical models complemented with mechanical laboratory tests to characterize strength, fatigue, and stability. The strength test evaluated device failures under extreme loads and was complemented with optimization procedures to improve the biomechanical behavior of the devices. The responses of the prototypes were characterized to improve their design and identify weak and strong regions in order to avoid posterior device failure in clinical applications. Combinations of the numerical and mechanical laboratory results were used to compare and validate the models. In addition, the results remark the importance of reducing the number of animals used in experimental tests by increasing computational and in vitro trials. © VC 2014 by ASME.Ítem On Calculus, Forces and Maths(Universidad EAFIT, 2008-11-01) González Cortes, Ana María; Equipo Universidad de los niñosÍtem Zylerberg, 1985 Contributions of the layer topology and mineral content to the elastic modulus and strength of fish scales(ELSEVIER SCIENCE BV, 2018-02-01) Murcia, S.; Miyamoto, Y.; Varma, M.P.; Ossa, A.; Arola, D.Fish scales are an interesting natural structural material and their functionality requires both flexibility and toughness. Our previous studies identified that there are spatial variations in the elastic properties of fish scales corresponding to the anatomical regions, and that they appear to be attributed to changes in the microstructure. In the present study, a model is proposed that describes the elastic behavior of elasmoid fish scales in terms of the relative contributions of the limiting layer and both the internal and external elasmodine. The mechanical properties of scales from the Megalops atlanticus (i.e. tarpon) were characterized in tension and compared with predictions from the model. The average error between the predicted and the experimental properties was 7%. It was found that the gradient in mineral content and aspect ratio of the apatite crystals in the limiting layer played the most important roles on the elastic modulus of the scales. Furthermore, misalignment of plies in the external elasmodine from the longitudinal direction was shown to reduce the elastic modulus significantly. This is one approach for modulating the fish scale flexibility for a high mineral content that is required to increase the resistance to puncture. © 2017