Weight and crash optimization of foam-filled three-dimensional ?S? frame

Pirmohammad

Lat. Am. j. solids struct.

2017

To mitigate shock forces in collision events, thin-walled members are used as energy absorber. In this article, crashworthiness of single-cell and multi-cell S-shaped members with various crosssections including triangular, square, hexagonal, decagon and circular were investigated under axial dynamic loading using finite element code LS-DYNA. Furthermore, crashworthiness of the S-rails with the same outer tubes and different inner ones was studied as well. The multi-cell members employed in this task were doublewalled tubes with several ribs connecting the inner and outer tubes together. Modified multi criteria decision making method known as complex proportional assessment (COPRAS) was used to rank the members using three conflicting crashworthiness criteria namely specific energy absorber (SEA), peak crash force (Fmax) and crash force efficiency (CFE). Moreover, the multi-cell S-shaped members were found to perform better than single-cell ones in terms of crashworthiness. In addition, the multi-cell S-rail with decagonal cross-section was found as the best energy absorber, and also the Srail having the same inner and outer tube with decagonal crosssection displayed desirable crashworthiness performance. Optimum geometry of this S-rail was eventually obtained from the parametric study.

Section: Parametric Studysupporting

confidence: 63%

Crashworthiness Analysis of S-Shaped Structures Under Axial Impact Loading

Pirmohammad

Lat. Am. j. solids struct.

2017

International Journal of Solids and Structures

“…Recently, much attention is given to the cellular material filled thin-walled structures (Chen, 2001;Hanssen et al, 2002;Kim et al, 2002;Santosa and Wierzbicki, 1999;Seitzberger et al, 2000). The studies showed that the interaction between metal or polymeric cellular material fillers and the supporting structures produces some desirable crushing behaviors and energy absorption properties.…”

Section: Introductionmentioning

confidence: 99%

Partition energy absorption of axially crushed aluminum foam-filled hat sections

Song

Zhong

et al. 2005

105

The ''interaction effect'' between aluminum foam and metal column that takes place when foam-filled hat sections (top-hats and double-hats) are axially crushed was investigated in this paper. Based on experimental examination, numerical simulation and analytical models, a systemic approach was developed to partition the energy absorption quantitatively into the foam filler component and the hat section component, and the relative contribution of each component to the overall interaction effect was therefore evaluated. Careful observation of the collapse profile found that the crushed foam filler could be further divided into two main energy-dissipation regions: densified region and extremely densified region. The volume reduction and volumetric strain of each region were empirically estimated. An analytical model pertinent to the collapse profile was thereafter proposed to find the more precise relationship between the volume reduction and volumetric strain of the foam filler. Combined the superfolding element model for hat sections with the current model according to the coupled method, each component energy absorption was subsequently derived, and the influence of some controlling factors was discussed. According to the finite element analysis and the theoretical modeling, when filled with foam, energy absorption was found to be increased both in the hat section and the foam filler, whereas the latter contributes predominantly to the interaction effect. The formation of the extremely densified region in the foam filler accounts for this effect.

“…Cross-sectional dimensions and material properties are the main considerations used to determine the stiffness, strength and energy absorption of box-type structures. Kim et al [9] applied loads to hydro-aluminum foam-filled S-shaped tubes. From the deformation pattern of the S-shaped tube, they concluded that ultra-light metallic foam-filling is a good way to strengthen S-frame members.…”

Section: Introductionmentioning

confidence: 99%

Crash analysis and energy absorption characteristics of S-shaped longitudinal members

Elmarakbi

Long

MacIntyre

2013

Thin-Walled Structures

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. a b s t r a c t This paper presents finite element simulations of the crash behavior and the energy absorption characteristics of thin S-shaped longitudinal members with variable cross-sections made of different materials to investigate the design of optimized energy-absorbing members. Numerical studies are carried out by simulation via the explicit finite element code LS-DYNA [1] to determine the desired variables for the design of energy-absorbing members. The specific energy absorption (SEA), the weight of the members and the peak force responses during the frontal impact are the main measurements of the S-shaped members' performance. Several types of inner stiffening members are also investigated to determine the influence of the additional stiffness on the crash behavior.