Estudio de elementos resistentes en la arquitectura mediante el método fotoelástico.

Sin resume

Aplicación de modelos autorregresivos a la simulación de las características físicas de envases de vidrio

Se presenta en este artículo la simulación de las características de envases de vidrio, mediante modelos auto regresivos (AR), siguiendo el enfoque Box-Jenkins. El artículo se presenta en dos partes: en la primera, se demuestra la adecuación de un modelo AR (2), para la simulación de los espesores a partir de las características estadísticas determinadas sobre cortes longitudinales de envases reales. En la segunda parte, se presenta la forma práctica que se ha desarrollado para la simulación de una muestra de veinte recipientes

CDIO Experiences in Biomedical Engineering: Preparing Spanish Students for the Future of Medicine and Medical Device Technology

Biomedical engineering is one of the more recent fields of engineering, aimed at the application of engineering principles, methods and design concepts to medicine and biology for healthcare purposes, mainly as a support for preventive, diagnostic or therapeutic tasks. Biomedical engineering professionals are expected to achieve, during their studies and professional practice, considerable knowledge of both health sciences and engineering. Studying biomedical engineering programmes, or combining pre-graduate studies in life sciences with graduate studies in engineering, or vice versa, are typical options for becoming qualified biomedical engineering professionals, although there are additional interesting alternatives, to be discussed. According to our experience, the graduates and post-graduates from multidisciplinary engineering programmes, not just from biomedical engineering, but also from more traditional fields including industrial, mechanical and telecommunications engineering, can play varied and very relevant roles in the biomedical industry and in extremely complex biomedical device development projects. In spite of the different ways of becoming a professional of the biomedical engineering field, it is true that their impact as successful professionals can be importantly increased, by means of an adequate integration into their curricula of fundamental biomedical engineering design concepts, methodologies and good practices, applied to the development of biomedical devices. In this study we present the complete development and comparative study of three courses, belonging to different plans of study taught at the Technical University of Madrid and benefiting from using a CDIO approach focused on the development of biomedical devices. The three courses are “Development of Medical Devices”, “Bioengineering Design” and “Biomedical Engineering”, respectively belonging to the “Bachelor’s Degree in Biomedical Engineering”, to the “Master’s Degree in Industrial Engineering” and to the “Master’s Degree in Mechanical Engineering”. During the courses, groups of students live through the development process of different biomedical devices aimed at providing answers to relevant social needs. Depending on their background and European credits assigned to the different courses, students carry out more conceptual projects or are able to live through more complete CDIO experiences. Main benefits, lessons learned and future challenges, linked to these courses, are analyzed, taking account of the results from 2014-2015 academic year

Estudio de deformaciones en la articulación del hombro con técnicas experimentales optomecánicas

El complejo articular del hombro supone un reto en el conocimiento biomecánico del mismo debido a su complejidad y sus numerosas estructuras implicadas. Este estudio presenta un modelo basado en técnicas de fotoelasticidad que representa la distribución de tensiones al colocar el hombro en una posición de equilibrio de 90º de abducción. Mediante la congelación de tensiones podemos analizar la distribución de las mismas tanto en la superficie como en el interior de la escápula y el húmero. El presente modelo aporta un análisis cualitativo de la distribución de las tensiones en el hombro, que puede ser de utilidad como complemento a otros modelos biomecánicos numéricos publicados

The effects of additional hollow cylinder coated to external fixator screws for treating pilon fracture: A biomechanical perspective

An external fixator is a promising medical device that could provide optimum stability and reduce the rate of complications in treating bone fracture during intervention period. It is noted that the biomechanics behaviour of device can be altered by introducing more features such as material suitability and additional components. Therefore, this study was conducted via finite element method to investigate the effects of additional hollow cylinder coated with external fixator screws in treating Type III pilon fracture. Finite element models which have been validated with experimental data were used to simulate stresses at the pin-bone interface and relative micromovement at interfragmentary fractures during swing (70 N load) and stance phases (350 N load). All bones and external fixators were assigned with isotropic material properties while the cartilages were simulated with hyper-elastic. For the hollow cylinder, polyethylene was assigned due to its properties which are equivalent to the bone. From the results, it is found that stresses at the pin-bone interface for the coated screws were reduced to 54% as compared to the conventional fixator. For the micromovement, there was no difference between both models, whereby the value was 0.03 mm. The results supported previously published literature, in which high stresses are unavoidable at the interface, fortunately, those stresses did not exceed the ultimate strength of bone, which is safe for treating patients. In conclusion, if patients are allowed to bear weight bearing, the external fixator with coated screws is a more favourable option to be fixed into the bone to avoid complications at the interface

Estudio de deformaciones en la articulación del hombro con técnicas experimentales optomecánicas

El complejo articular del hombro supone un reto en el conocimiento biomecánico del mismo debido a su complejidad y sus numerosas estructuras implicadas. Este estudio presenta un modelo basado en técnicas de fotoelasticidad que representa la distribución de tensiones al colocar el hombro en una posición de equilibrio de 90º de abducción. Mediante la congelación de tensiones podemos analizar la distribución de las mismas tanto en la superficie como en el interior de la escápula y el húmero. El presente modelo aporta un análisis cualitativo de la distribución de las tensiones en el hombro, que puede ser de utilidad como complemento a otros modelos biomecánicos numéricos publicados

Kinematics based physical modelling and experimental analysis of the shoulder joint complex

The purpose of this work is to develop an experimental physical model of the shoulder joint complex. The aim of this research is to validate the model built and identify the forces on specified positions of this joint. The shoulder musculoskeletal structures have been replicated to evaluate the forces to which muscle fibres are subjected in different equilibrium positions: 60º flexion, 60º abduction and 30º abduction and flexion. The physical model represents, quite accurately, the shoulder complex. It has 12 real degrees of freedom, which allows motions such as abduction, flexion, adduction and extension and to calculate the resultant forces of the represented muscles. The built physical model is versatile and easily manipulated and represents, above all, a model for teaching applications on anatomy and shoulder joint complex biomechanics. Moreover, it is a valid research tool on muscle actions related to abduction, adduction, flexion, extension, internal and external rotation motions or combination among them.Este trabajo consiste en desarrollar un modelo físico experimental del complejo articular del hombro. El objetivo en esta investigación es validar el modelo construido e identificar las fuerzas en posiciones específicas de esta articulación. Se han reproducido las estructuras musculo-esqueléticas del hombro para evaluar las fuerzas a las que están sometidas las fibras musculares en diferentes posiciones de equilibrio: flexión 60º, abducción 60º y aducción más flexión 30º. El modelo físico representa con suficiente aproximación a la realidad el complejo del hombro; posee 12 grados reales de libertad, lo cual permite realizar movimientos como abducción, flexión, aducción y extensión y calcular las fuerzas resultantes de los músculos representados. El modelo físico construido es versátil y fácilmente manipulable y constituye, por encima de todo, un modelo para aplicaciones didácticas en anatomía y biomecánica del complejo articular del hombro. Así mismo, es una herramienta de investigación válida sobre las acciones musculares asociadas a los movimientos de abducción, aducción, flexión, extensión, rotación interna y externa o combinaciones de los mismos

Análisis de métodos de fabricación de modelos sintéticos de hombro con componentes protésicos de la artroplastia total aptos para estudios de cargas y ensayos fotoelásticos

En el presente trabajo se desarrollan y comparan dos métodos de fabricación de modelos con dos tipos de prótesis invertidas: Delta (Depuy Sinthes) y SMR (Lima). Los modelos obtenidos a partir de técnicas de reproducción de huesos conservando los elementos anatómicos y accidentes óseos [3], son aptos para estudios con Fotoelasticidad 3D, técnica que permite evaluar la implantación y el problema de contacto de las prótesis con las estructuras óseas

Kinematics based physical modelling and experimental analysis of the shoulder joint complex

The purpose of this work is to develop an experimental physical model of the shoulder joint complex. The aim of this research is to validate the model built and identify the forces on specified positions of this joint. The shoulder musculoskeletal structures have been replicated to evaluate the forces to which muscle fibres are subjected in different equilibrium positions: 60º flexion, 60º abduction and 30º abduction and flexion. The physical model represents, quite accurately, the shoulder complex. It has 12 real degrees of freedom, which allows motions such as abduction, flexion, adduction and extension and to calculate the resultant forces of the represented muscles. The built physical model is versatile and easily manipulated and represents, above all, a model for teaching applications on anatomy and shoulder joint complex biomechanics. Moreover, it is a valid research tool on muscle actions related to abduction, adduction, flexion, extension, internal and external rotation motions or combination among them

Biomechanical features of six design of the delta external fixator for treating Pilon fracture: a finite element study

Pilon fractures can be caused by high-energy vertical forces which may result in long-term patient immobilization. Many experts in orthopedic surgery recommend the use of a Delta external fixator for type III Pilon fracture treatment. This device can promote immediate healing of fractured bone, minimizing the rate of complications as well as allowing early mobilization. The characteristics of different types of the Delta frame have not been demonstrated yet. By using the finite element method, this study was conducted to determine the biomechanical characteristics of six different configurations (Model 1 until Model 6). CT images from the lower limb of a healthy human were used to reconstruct three-dimensional models of foot and ankle bones. All bones were assigned with isotropic material properties and the cartilages were assigned to exhibit hyperelasticity. A linear link was used to simulate 37 ligaments at the ankle joint. Axial loads of 70 and 350 N were applied at the proximal tibia to simulate the stance and swing phase. The metatarsals and calcaneus were fixed distally in order to prevent rigid body motion. A synthetic ankle bone was used to validate the finite element model. The simulated results showed that Delta3 produced the highest relative micromovement (0.09 mm, 7 μm) during the stance and swing phase, respectively. The highest equivalent von Mises stress was found at the calcaneus pin of the Delta4 (423.2 MPa) as compared to others. In conclusion, Delta1 external fixator was the most favorable option for type III Pilon fracture treatment