Improving the Energy Absorption of Cruciform With Large Global Slenderness Ratio by Kirigami Approach and Welding Technology

2019 ◽  
Vol 86 (8) ◽  
Author(s):  
Caihua Zhou ◽  
Tong Li ◽  
Shizhao Ming ◽  
Zhibo Song ◽  
Bo Wang

Conventional energy absorber usually employs stubby thin-walled structures. Compared with the limited number of stubby thin-walled structures, an equipment has a large number of slender thin-walled structures that has the potential to be used for energy absorption purpose as well. Therefore, improving the energy absorption capacity of these slender thin-walled structures can significantly benefit the crashworthiness of the equipment. However, these slender structures are inclined to deform in Euler buckling mode, which greatly limits their application for energy absorption. In this paper, kirigami approach combined with welding technology is adopted to avoid the Euler buckling mode of a slender cruciform. Both finite element simulations and experiments demonstrated that the proposed approach can trigger a desirable progressive collapse mode and thus improve the energy absorption by around 155.22%, compared with the conventional cruciform. Furthermore, parametric studies related to the kirigami pattern and global slenderness ratio (GSR) are conducted to investigate the improvement of this proposed approach on the energy absorption and the maximum critical value of GSR.

2014 ◽  
Vol 1019 ◽  
pp. 96-102
Author(s):  
Ali Taherkhani ◽  
Ali Alavi Nia

In this study, the energy absorption capacity and crush strength of cylindrical thin-walled structures is investigated using nonlinear Finite Elements code LS-DYNA. For the thin-walled structure, Aluminum A6063 is used and its behaviour is modeled using power-law equation. In order to better investigate the performance of tubes, the simulation was also carried out on structures with other types of cross-sections such as triangle, square, rectangle, and hexagonal, and their results, namely, energy absorption, crush strength, peak load, and the displacement at the end of tubes was compared to each other. It was seen that the circular cross-section has the highest energy absorption capacity and crush strength, while they are the lowest for the triangular cross-section. It was concluded that increasing the number of sides increases the energy absorption capacity and the crush strength. On the other hand, by comparing the results between the square and rectangular cross-sections, it can be found out that eliminating the symmetry of the cross-section decreases the energy absorption capacity and the crush strength. The crush behaviour of the structure was also studied by changing the mass and the velocity of the striker, simultaneously while its total kinetic energy is kept constant. It was seen that the energy absorption of the structure is more sensitive to the striker velocity than its mass.


Author(s):  
Zhichao Li ◽  
Subhash Rakheja ◽  
Wen-Bin Shangguan

Thin-walled structures are widely used as energy absorbers in automotive vehicles due to their lightweight and high-energy absorption efficiency. In order to improve the energy absorption characteristics of thin-walled structures subjected to different loading angles, different types of novel multi-cell structures are proposed in this paper. The numerical method is used to study the crushing behaviors of the proposed multi-cell structures under different loading angles. It is found that the proposed multi-cell structures have considerably small initial peak force under axial load and avoid the appearance of global buckling deformation mode under oblique loads. Moreover, reasonably distributed wall thickness for each square tube in the thin-walled structure can enhance its energy absorption capacity under different loading angles.


Author(s):  
Fengxiang Xu ◽  
Suo Zhang ◽  
Kunying Wu

Thin-walled structures with graded property have been paid more attention in recent years due to their significant balance between lightweight and crashworthiness. However, few studies have been focused on energy absorption capacity of thin-walled conical tubes with graded diameters. In this paper, the thin-walled conical aluminum tubes with nonlinearly-graded diameters are introduced and their corresponding crashing characteristics are performed. The diameters are assumed to nonlinearly vary according to a power-law distribution function primarily determined by a graded exponent n. It is found that the total weight of thin-walled conical tubes decreases with the increasing of the gradient exponent. The energy-absorbed performances such as specific energy absorption, initial peak crashing force, and mean crashing force of those graded tubular structures are numerically analyzed. And then the effects of various geometric parameters such as the gradient exponent, deformation distance, and diameter range on crashing behaviors are further evaluated. It is observed that those parameters especially the gradient exponent has significantly obvious effects on crashworthiness of the proposed nonlinearly graded tubes. It is also noted that the straight conical structure with gradient n = 1.0 may not show the best energy absorption characteristics compared with other gradients. The work could provide valuable information for effective design of thin-walled energy-absorbing structures with variable geometrical parameters.


2011 ◽  
Vol 213 ◽  
pp. 88-92 ◽  
Author(s):  
Qing Chun Wang ◽  
Hao Long Niu ◽  
Guo Quan Wang ◽  
Yu Xin Wang

Different aluminum foam filling lengths were used to increase the bending energy absorbing capacity of the popularly used hat sections. Bending energy-absorption performance of the thin-walled tubes was numerically studied by explicit non-linear software LS-Dyna. First empty hat section subjected to quasi-static bending crushing was simulated, then structures with different aluminium foam filling lengths were calculated, finally energy absorption capacity of these structures were compared. Calculation results showed that, the internal energy absorbed and mass specific energy absorption capacity of foam filled thin walled structures were increased significantly compared to the empty sections. The reason of the improvement was mainly due to the contact of the aluminium foam and the structure. Aluminium foam filling is a promising method for improving lateral energy absorbing capacity of thin-walled sections.


2014 ◽  
Vol 599 ◽  
pp. 141-144 ◽  
Author(s):  
M. Afrasiab ◽  
G. Faraji ◽  
V. Tavakkoli ◽  
M.M. Mashhadi ◽  
A.R. Bushroa

Author(s):  
Sean Jenson ◽  
Muhammad Ali ◽  
Khairul Alam

Abstract Thin walled axial members are typically used in automobiles’ side and front chassis to improve crashworthiness of vehicles. Extensive work has been done in exploring energy absorbing characteristics of thin walled structural members under axial compressive loading. The present study is a continuation of the work presented earlier on evaluating the effects of inclusion of functionally graded cellular structures in thin walled members under axial compressive loading. A compact functionally graded composite cellular core was introduced inside a cross tube with side length and wall thickness of 25.4 mm and 3.048 mm, respectively. The parameters governing the energy absorbing characteristics such as deformation or collapsing modes, crushing/ reactive force, plateau stress level, and energy curves, were evaluated. The results showed that the inclusion of composite graded cellular structure increased the energy absorption capacity of the cross tube significantly. The composite graded structure underwent progressive stepwise, layer by layer, crushing mode and provided lateral stability to the cross tube thus delaying local tube wall collapse and promoting large localized folds on the tube’s periphery as compared to highly localized and compact deformation modes that were observed in the empty cross tube under axial compressive loading. The variation in deformation mode resulted in enhanced stiffness of the composite structure, and therefore, high energy absorption by the structure. This aspect has a potential to be exploited to improve the crashworthiness of automobile structures.


Symmetry ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 175
Author(s):  
Wenjing Shen ◽  
Hongyuan Zhou ◽  
Xuejian Zhang ◽  
Xiaojuan Wang

Foam concrete exhibits long stress plateau with increasing strain subjected to compression and absorbs a considerable amount of energy, making them promising for building and structure protection. In the present study, hexagonal concrete honeycombs are employed to approximately represent foam concrete, whose response and energy absorption subjected to dynamic in-plane compression are investigated with smooth particle hydrodynamics method. The response modes under low to high velocity crushing are numerically investigated, with which the critical velocity separating quasi-static response and progressive collapse mode is determined. Furthermore, the dynamic energy absorption capacity is examined and discussed.


2009 ◽  
Vol 76 (4) ◽  
Author(s):  
S. B. Bodlani ◽  
S. Chung Kim Yuen ◽  
G. N. Nurick

This two-part article reports the results of experimental and numerical works conducted on the energy absorption characteristics of thin-walled square tubes with multiple circular hole discontinuities. Part I presents the experimental tests in which dynamic and quasistatic axial crushings are performed. The mild steel tubes are 350 mm in length, 50 mm wide, and 1.5 mm thick. Circular hole discontinuities, 17 mm in diameter, are laterally drilled on two or all four opposing walls of the tube to form opposing hole pairs. The total number of holes varies from 2 to 10. The results indicate that the introduction of holes decreases the initial peak force but an increase in the number of holes beyond 2 holes per side does not further significantly decrease the initial peak force. The findings show that strategic positioning of holes triggers progressive collapse hence improving energy absorption. The results also indicate that the presence of holes may at times disrupt the formation of lobes thus compromising the energy absorption capacity of the tube. In Part II, the finite element package ABAQUS/EXPLICIT version 6.4–6 is used to model the dynamic axial crushing of the tubes and to investigate the action of the holes during dynamic loading at an impact velocity of 8 m/s.


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