Security and defence of mobile systems under impact

The Group “Dynamics and Fracture of Structural Elements” offers its experience in Solid Mechanics analysis for the study of the impact protection of vehicles, aircrafts and persons. The Group activities have a strong research component, in which numerical simulation tools as well as sophisticated experimental techniques are employed. This technological offer could be of interest to automobile companies (impact and collision security), aeronautical companies (impact of external body on fuselage, attack, and fragments o ice) and defence companies (special armours for mobile systems and persons).Contrato Programa de Comercialización e Internacionalización. Sistema Regional de Investigación Científica e Innovación Tecnológica. (Comunidad de Madrid; Universidad Carlos III de Madrid

Editorial

Tenemos intención de reunir a las ciudades mediterráneas en las que se ejerzan los estudios de Arquitectura y componer con ellas una red que pueda ofrecer soluciones naturales y expertas. Esta décima entrega de nuestra revista P+ C pretende demostrar que eso es posible. Reúne por primera vez las energías de Cartagena con las de Palermo, Cagliari, Nápoles, Reggio-Calabria, Roma, Siracusa y Venecia. Giuseppe Di Benedetto y Tiziana Campisi, docentes en Palermo, han coordinado los artículos de los profesores mediterráneos italianos que ahora publicamos

Editorial

El editorial está dedicado a la memoria del profesor de la Escuela Técnica Superior de Arquitectura y Edificación, Elías Hernández Albaladejo fallecido el 17 de enero de 2015

Finite element simulation of steel ring fragmentation under radial expansion

24 pages, 25 figures.This paper presents a numerical analysis of the expansion of a mild steel ring with of 50 mm diameter, 1 mm thickness and a cross section of 1 mm2. A hardening relation which takes into account strain, strain rate and temperature is proposed to define precisely the thermoviscoplastic behaviour of the material considered in the study. As a second step, an algorithm to integrate the thermoviscoplastic constitutive equations, including the hardening law, is implemented in the commercial finite element code ABAQUS/Explicit via a user subroutine. Finally, this tool is used to simulate the problem of a ring expanding radially in a broad range of strain rates, covering both low and high initial velocities (from 1 to 370 m/s). The aim is to analyse the effect of loading velocity on the number of fragments resulting from the multiple failure of the ring and also the influence of the hardening behaviour of the material on the number of fragments and on the failure mode of the ring, considering different values of the plastic strain hardening exponent n0. A simple failure criterion was used, based on a critical value of the equivalent strain which depends on the hardening exponent. The numerical predictions, in perfect agreement with the experimental observations, are compared with several analytical or numerical models used to solve the same problem in other materials such as aluminium, steel or copper.Publicad

Análisis del comportamiento frente a impacto de elementos de estructuras aeronáuticas y aeroespaciales

El grupo de “Dinámica y Fractura de Elementos Estructurales” ofrece su experiencia en el análisis de problemas de mecánica de sólidos para estudiar el comportamiento de elementos estructurales sometidos a cargas de impacto. Para ello el grupo dispone de herramientas de simulación y equipamiento experimental específico para sus actividades de investigación. Sus actividades pueden resultar atractivas a empresas aeronáuticas que precisen de técnicas de análisis no convencionales

Using an analytical model of simulation in the design of light-weight armours

9 pages, 13 figures.This paper presents a model for the simulation of the impact of projectiles of high kinetic energy on lightweight ceramic/metal armours. The work was financed jointly by the Defence Ministries of Spain, Italy, Holland and Denmark as part of a project among nations for the development of tools for the design of this type of armour. The model consists of a series of differential equations incorporating the most essential phenomena of the impact process, formulated after a close study of a series of real fire tests. It features a nucleus of calculation into which the equations may in time be integrated, and may also include a user interface. This practical, preliminary design tool's efficacy is amply confirmed by test results.The authors are indebted to the Research & Development Department of Empresa Nacional Santa Bárbara (Spain) for the performance of the ballistic tests and the X-ray shadowgraphs. This work is part of the EUCLID RTP 3.2 project, supported by the Ministries of Defence of Spain, Denmark, Holland and Italy. The above project has been developed with the collaboration of several companies and research centres of the aforementioned countries.Publicad