Publication: Modelo numérico para impactos de alta velocidad en blindajes cerámico-metálicos
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2015-09
Defense date
2015-10-06
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Abstract
Los blindajes bi-capa, o blindajes de dos materiales, han sido objeto de atención
desde hace varias décadas por sus altos niveles de protección balística, así como por
su reducido peso. Consisten en una placa exterior de alta dureza y una capa posterior
con un comportamiento dúctil, con el objetivo de que la primera debilite y decelere el
proyectil y la segunda mantenga en su sitio los restos fracturados de la placa delantera
y absorba la energía residual del proyectil. El conocimiento de estos sistemas de
protección es de mucho interés en el ámbito militar, en el aeronáutico, y otros campos,
dado el desarrollo reciente de materiales que pueden ser de relevancia para diseñar
nuevos blindajes ligeros con prestaciones mejoradas según las características que
ofrezca cada uno. Para llegar a buen fin en el desarrollo del trabajo, es importante que
el diseñador de blindajes posea un gran nivel de conocimiento del comportamiento
mecánico de los materiales con los que se va a trabajar, fundamentalmente los
criterios de fallo o rotura.
En este Trabajo Fin de Grado se estudia el comportamiento de elementos de
protección ligeros de doble capa, compuestos por una placa cerámica frontal
respaldada por otra metálica, frente a altas solicitaciones dinámicas. Para ello, se ha
utilizado el Método de Elementos Finitos (FEM) para generar un modelo de simulación
numérica con el código comercial explícito Abaqus, que ha permitido validar los
resultados experimentales propuestos por Sánchez Gálvez y Sánchez Paradela
(2009).
Además, se han comparado los resultados obtenidos con los expuestos en el modelo
numérico propuesto de R. Chi et al. (2012), que se utiliza para relacionar y analizar las
velocidades residuales y la velocidad de límite balístico con los espesores de placa
empleados. Además se ha intentado validar una serie de curvas analíticas para el
cálculo de la velocidad de límite balístico (BLV) propuestas por los mismos.
Finalmente, se ha estudiado el comportamiento de los blindajes cerámico/metálicos
para diferentes solicitaciones y condiciones de contorno.
Bi-layer shields have received attention for several decades due to their high ballistic protection levels, as well as its reduced weight. These shields have an outer plate of high hardness and a rear layer with a ductile behaviour. The first layer weakens and decelerates the projectile whereas the second layer keeps in place the fractured remains of the front plate and absorbs the residual energy of the projectile. The knowledge of these protection systems has interest in the military sector, in aeronautics and other fields, as there are recent materials that may be of relevance for new light shielding with improved performance arising from the features that gives each layer. For a good development of the shield, the designer should have a high level of knowledge of the mechanical behaviour of these materials, mainly the failure or breakage criteria. In this work, we analyse the behaviour of light bi-layer shields as protective elements, with a ceramic front plate backed by another metallic layer, under high dynamic loads. We use the Finite Elements Method (FEM) in order to generate a model of numerical simulation with the commercial code Abaqus/Explicit. We have validated the experimental results by Sánchez Gálvez and Sanchez Paradela (2009). We have also compared our results with those obtained by the numerical model proposed by R. Chi et al. (2012), used to relate and analyze the residual speeds and the ballistic limit speed with the thickness of the bi-layer plates. Moreover, we have attempted to validate their proposed analytical curves for the calculation of the ballistic limit velocity (BLV). Finally, we have studied the behaviour of the ceramic/metal shields for different loads and boundary conditions.
Bi-layer shields have received attention for several decades due to their high ballistic protection levels, as well as its reduced weight. These shields have an outer plate of high hardness and a rear layer with a ductile behaviour. The first layer weakens and decelerates the projectile whereas the second layer keeps in place the fractured remains of the front plate and absorbs the residual energy of the projectile. The knowledge of these protection systems has interest in the military sector, in aeronautics and other fields, as there are recent materials that may be of relevance for new light shielding with improved performance arising from the features that gives each layer. For a good development of the shield, the designer should have a high level of knowledge of the mechanical behaviour of these materials, mainly the failure or breakage criteria. In this work, we analyse the behaviour of light bi-layer shields as protective elements, with a ceramic front plate backed by another metallic layer, under high dynamic loads. We use the Finite Elements Method (FEM) in order to generate a model of numerical simulation with the commercial code Abaqus/Explicit. We have validated the experimental results by Sánchez Gálvez and Sanchez Paradela (2009). We have also compared our results with those obtained by the numerical model proposed by R. Chi et al. (2012), used to relate and analyze the residual speeds and the ballistic limit speed with the thickness of the bi-layer plates. Moreover, we have attempted to validate their proposed analytical curves for the calculation of the ballistic limit velocity (BLV). Finally, we have studied the behaviour of the ceramic/metal shields for different loads and boundary conditions.
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Keywords
Método de Elementos Finitos (FEM), Blindaje, Velocidad de límite balístico (BLV), Resistencia de materiales, Ensayo de materiales, Blindajes cerámico/metálicos, Mecánica de sólidos