Crashworthiness Analysis And Optimization Design Of Special-shaped Thin-walled Structure

Thin-walled structures are widely used as energy absorbing devices in the vehicular and aeronautical frontal structures for their proven advantages on lightweight and crashworthiness. A largr number of scholars explored the crashworthiness of thin-walled tubes with traditional cross-sectional shapes(e.g. circular, rectangle, square, hexagonal, octagonal and ellip tical cross-sections) under axail loading. To better understand energy absorption of thin-walled tubes and fully explore their potential as energy absorbers, this paper carried out a series of studies for the special thin-walled structure. Based on straight circular tube, changing the radial and axial configuration by special functions, the following researchs have been carried out:(1) this paper utilize Fourier series expansion to introduces a series of novel tubal configuration, namely Fourier various section tubes(FVSTs), to investigate their crashworthiness, and explore the potential of FVSTs. Through validating the finite element(FE) models established, the effects of cross-section configuration, perimeter and thickness of FVSTs on collapse mode and energy absorption were investigated. The results showed that the collapse modes of FVSTs easily are effect by cross-section configuration, perimeter and thickness, and FVSTs have significant potential on energy absorption. Finally, a discrete optimization is conducted to obtain the optimized FVST for maximizing specific energy absorption(SEA) under the constraint of the initial peak crushing force( IPCF). The optimal FVSTs are of even more superior crashworthiness and great potential as an energy absorber.(2) this paper introduces a novel tubal configuration, namely sinusoi dal corrugation tubes(SCTs), to control the collapse mode, and minimize the IPCF and the fluctuations. Through validating the finite element(FE) models established, the effects of wavelength, amplitude, thickness and diameter of SCTs on collapse mode and energy absorption were investigated. The results showed that SCTs can make the deformation mode more controllable and predictable, which can be transformed from mixed modes to ring modes by simply changing the wavelength and amplitude. Compared with the traditional straight tube of a circular cross-section, the IPCF is also reduced appreciably. Furthermore, SCTs have lower fluctuation in the force–displacement curves than those traditional straight circular tubes. Finally, a multi-objective optimization is conducted to obtain the optimized SCT configuration for maximizing specific energy absorption( SEA), minimizing IPCF under the constraint of fluctuation criterion. The optimal SCTs are of even more superior crashworthiness and great potential as an energy absorber.