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Abstract
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Many research works recently have attempted to use different computational and numerical simulation techniques to model the material thermal large deformation processes for the design of high performance profiles in new roadside infrastructure designs. The material processes for the lightweight crash-capable parts are among the most delicate processes for the material scientist and designing engineers. The forming and extrusion of lightweight alloys involves thermal effects, large deformation, complex geometries and free surface boundaries. The conventional approach towards the simulation of extrusion process using Finite Element (FE) or Finite Volume (FV) has serious short comes even when updated Lagrangian, Eulerian or ALE techniques are employed. During past decades, there has been considerable effort to simulate the whole extrusion process by splitting it into steady state (using Eulerian technique) and transient (using Updated Lagrangian technique) processes.
The damage initiation, progression and also failure of lightweight hollow profiles during crash are a result of accumulated damage under plastic deformation. Based on the damage theories, as the loading condition is changing for the material, a plastic deformation may take place which would progressively increase the damage in the component. The accumulated damage would ultimately result in the failure of the cross-section. There are different numerical models to calculate the damage evolution, fracture initiation and also its propagation using continuum and/or discrete damage techniques. In the present study, following an in-depth study of material processing and its absorption capacities, folding modes and geometric/production constrains; a frame work has been setup to develop and test an optimised aluminium extruded profiles for best dynamic and crash performance characteristics. The numerical dynamic simulations (including fatigue, vehicle buffeting …) and virtual crash performance of lightweight hollow profiles have been considered for the design of new generation of roadside signals, lighting posts… for future.
The complicated mathematical basis of large deformations, plasticity, contact and folding have been developed and special attention has been devoted to the plastic deformation, rate dependency and tailored yield locus. To assess the dynamic performance and energy absorption of these profiles, a full transient dynamic analysis can be performed using a time history dynamic loading. The new absorbing component design has been checked and verified using a result of carefully-setup experiments work and also advanced explicit simulation runs. One of the main contributions of this paper is to show the applicability and reliability of the numerical simulation approach for the crash performance of new lightweight roadside entities.
Language: en |