Stiffness control in adaptive thin-walled laminate composite beams

Abstract

a b s t r a c tThe aim of this paper is to verify the control of the stiffness that is feasible to achieve in a thin walled box beam made from a laminate by including an adaptive material with variable stiffness. In this work, a material having a strongly varying Young Modulus under minor temperature changes was included in the cross section. An analytical model was used to estimate the position of shear centre and the axial, bending, torsional, and shear stiffnesses of the cross section. Two cross sections were analysed, one with an adaptive wall and another with two adaptive walls. In both sections, the torsional stiffness could be strongly altered with minor temperature variations. In the section with one adaptive wall, the shear centre and thus the bending twist coupling was also strongly modified. A study was made of the influ ence on the control of stiffnesses exerted by the overall cross section thickness and the thickness of the adaptive walls.

Toward lightweight smart automotive hood structures for head impact mitigation: Integration of active stiffness control composites

“…Relatively recently, various promising concepts for material systems with variable stiffness have been presented in the literature (Bachinger, 2015; Bachinger et al, 2014, 2015; Gandhi and Kang, 2007; Henke and Gerlach, 2016; Maples et al, 2014; Rivas and Barbero, 2016; Tridech et al, 2013; Yuen et al, 2016). Among these are active stiffness control (ASC) approaches for high-performance carbon fiber reinforced polymer (CFRPs; Bachinger, 2015; Bachinger et al, 2014, 2015).…”

“…The main innovation of the presented hood design concept with respect to other state-of-the-art hood designs is the application and integration of a recently developed ASC carbon fiber reinforced polymer (CFRP) material (Bachinger et al, 2014(Bachinger et al, , 2015. Although some investigations on active stiffness variation based on temperature control are available in the literature for beams (Gandhi and Kang, 2007;Rivas and Barbero, 2016), the present communication is, to the authors' knowledge, the first design concept with ASC composite material applied to an automotive component. The integration of the ASC material in order to achieve improved pedestrian safety led to several innovative design solutions in the geometry of the inner hood support structure.…”