Nowadays, most energy absorbing devices used in industry absorb energy through permanent deformation. In some cases, consumers have to repair or even replace energy absorbers even after a mild collision. The work presented in this paper proposes a novel re-usable solution in the form of a hybrid bumper-crush can design where a recoverable structure is integrated into the bumper beam and crush can for a mild collision situation in addition to the traditional energy absorbers recommended for more severe collisions. The main investigation is focused around the performance and optimisation of Negative Stiffness honeycomb, the recoverable structure and honeycomb-filled elements. A comprehensive study was undertaken to investigate numerically the behaviour of these energy absorbing structures under crash conditions, corresponding to real scenarios and simulated using a specially developed finite element model.
Aluminium composite sandwich panels are widely used to enhance the design of structures subjected to dynamic mechanical loading in thermally harsh environments. Spacecraft structures fall into this category because typical environmental conditions include combined and variable mechanical and thermal loading. Usually mechanical loadings arise as a consequence of localised structural dynamics and the thermal loadings are attributable principally to the effects of solar irradiation and eclipse during the vehicle's orbit. Together these have the potential to influence satellite de-point in particular. Therefore, building a combined physics model which is representative of the thermal and mechanical loadings has emerged as an interesting and useful aim, which can be thought of as defining an important thermoelastic deformation problem in this application. The performance of such a structure loaded in this way could obviously be considered in the context of separate thermodynamic and mechanical interpretations. However, multiphysics modelling is currently in hand based on the premise that the pseudo-static thermal loadings and the mechanical loadings encountered in various operating environments are not necessarily decoupled processes, and this will be the subject of a separate publication. The analytical modelling fully represents both static and dynamic mechanical and thermal loading conditions.It has become clear that predictive accuracy may be compromised by separation of the phenomena, at least without the introduction of a judicious correction factor. Therefore, in this paper an attempt has been made to identify experimentally the presence, and then to understand the attendant effects, of the coupling between the thermal and mechanical effects in an aluminium composite sandwich panel under test. The authors have performed a series of experiments on an aluminium honeycomb composite panel under three-point mechanical bending and controlled environmental temperature. The panel was subjected to a controllable, centrally located, very slowly increasing mechanical load in conjunction with thermal loading in the form of precisely controlled lowered and elevated environmental temperature. The tests were performed on a computer controlled Instron 8801 100 kN test machine for which the rate of change of applied mechanical load was automatically linked through feedback control to the rate of change of displacement. This ensured that the exact load-deflection profile can be obtained, even for materials with highly nonlinear characteristics.Both forms of loading have been shown to influence the displacement of the panel in significant ways, thereby confirming the importance of a combined physics approach.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.