Energy Absorption Characteristics of Axially Compressed Double Wall Foam Filled and Empty Square Tubes

Author(s):  
Raghu V. Prakash ◽  
Sanjay Toshniwal

Abstract Occupant safety has become increasingly important in the recent times. At the instance of an accident or collision, structures with high energy absorption can provide better occupant safety. Thin-walled tubes are widely used as energy absorbers in automobiles and other structures. In the present work, crashworthiness characteristics of double wall empty and double wall foam filled tubes are investigated. Thin wall extruded aluminum square tubes are used in this study. Polymer foam of three different densities, viz., 40 kg/m3, 80 kg/m3, 140 kg/m3 was used as filler material between the two tubes to fabricate a double wall foam filled tube. Both parallel and diamond configurations were considered for double walled empty and foam filled configurations. All the specimens were compressed at a displacement rate of 100 mm/min. Crushing of different configurations was numerically analyzed using nonlinear finite element tool LS-Dyna®. In double wall empty configuration, diamond arrangement absorbed more energy compared to parallel due to the interaction between inner and outer tubes. Results indicate that energy absorption increases with the filling of foam. Compared to double wall tubes, the maximum increase in energy absorption of ∼ 50% is observed in foam filled tubes. Using Computed Tomography (CT) scan of specimens, it is observed that foam filling alters the crushing behavior of the inner and outer tubes.

2020 ◽  
Vol 12 (5) ◽  
pp. 168781402092413
Author(s):  
Lai Hu ◽  
Jun Zha ◽  
Yaolong Chen

This study conducted an investigation on transverse quasi-static three-point loading on a circular aluminum tube and its characteristic plastic failure and energy-absorption behaviors. The thin wall thickness of the aluminum tube, the various diameter and thickness ratios ( D/ t) of the tube, and the tube length are important control parameters. Experimental data for different span length and thickness ratios of the tube were characterized and correlated to its plastic collapse behavior. A simulation model by computational analysis using ANSYS was also conducted as a comparative study. The results of the study found that transverse three-point bend loading (ASTM F290) of a circular aluminum tube underwent different stages of deformation, from initial pure crumpling to crumpling and bending, and finally, structural rupture. The results of master curve analysis found that regions of high energy absorption and low energy absorption can be classified with respect to the characteristic tubular deformation. High energy absorption deformation is correlated with a short span length and higher D/ t ratio, and vice versa for low energy absorption deformation of the circular aluminum tube. Simulation analysis also predicted similar characteristic trends of deformation behavior in the experiment, with a less than 3% average coefficient of variation.


Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4304
Author(s):  
Miroslaw Ferdynus ◽  
Patryk Rozylo ◽  
Michal Rogala

The paper presents the results of numerical tests of impact and energy absorption capacity of thin-walled columns, subjected to axial impact loading, made of aluminum alloy, and having a square cross-section and spherical indentations on their lateral surfaces. The numerical models were validated using an experiment that was conducted on the Instron CEAST 9350 High Energy System drop hammer. Material properties of the applied aluminum alloy were determined on the basis of a static tension test. The crushing behavior of the columns and some crashworthiness indicators were investigated. On the basis of the results of the conducted analyses, conclusions were drawn about the most beneficial design/constructional variants in terms of achieved crashworthiness parameters.


2018 ◽  
Vol 22 (4) ◽  
pp. 929-947 ◽  
Author(s):  
LL Yan ◽  
B Yu ◽  
B Han ◽  
QC Zhang ◽  
TJ Lu ◽  
...  

In this study, a closed-cell aluminum foam was filled into the interspaces of a sandwich panel with corrugated cores to form a composite structure. The novel structure is expected to have enhanced foam-filled cores with high specific strength and energy absorption capacity. An out-of-plane compressive load under low-velocity impact was experimentally and numerically carried out on both the empty and foam-filled sandwich panels as well as on the aluminum foam. It is found that the empty corrugated sandwich panel has poor energy absorption capacity due to the core member buckling compared to that of the aluminum foam. However, by the filling of the aluminum foam, the impact load resistance of the corrugated panel was increased dramatically. The loading-time response of the foam-filled panel performs a plateau region like the aluminum foam, which has been proved to be an excellent energy absorption material. Numerical results demonstrated that the aluminum foam filling can decrease the corrugated core member defects sensitivity and increase its stability dramatically. The plastic energy dissipation of the core member for the foam-filled panel is much higher than that of the empty one due to the reduced buckling wavelength caused by the aluminum foam filling.


2010 ◽  
Vol 10 (1) ◽  
pp. 1-17 ◽  
Author(s):  
AL EMRAN ISMAIL

The concerns of automotive safety have been given special attention in order to reduce human fatalities or injuries. One of the techniques to reduce collision impact or compression energy is by filling polymeric foam into metallic tubes. In this work, polyurethane foam was introduced into the steel extrusion tubes and quasi-statically compressed at constant cross-head displacement. Different tube thicknesses and foam densities were used and these parameters were related to the crashworthiness aspect of the foam-filled structures. It is found that both tube thickness and foam density played an important role in increasing the crashworthiness behaviours of the structures but when the tube thickness reached certain value, foam density unable to properly work in increasing the energy absorption of the structures.


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.


2012 ◽  
Vol 626 ◽  
pp. 1038-1041 ◽  
Author(s):  
Akbar Othman ◽  
Shahrum Abdullah ◽  
Ahmad Kamal Ariffin ◽  
Nik Abdullah Nik Mohamed ◽  
Helmi Rashid

The present papers determine the effect of composite pultrusion square tubes E-glass polyester empty and polymeric foam-filled subjected to axial compressive loading. The specimens of square composite pultrusion were compressed experimentally under axial loadings to examine the effect of empty and polymeric foam-filled with different wall-thickness. The wall-thickness was used in this study were 2.1 and 2.4 mm. During the experimental observation, three characteristic crushing stages were identified as initial peak load, progressive crushing and compaction zone stages. The composite pultrusion square tube profile were analyzed and investigated in terms of crashworthiness parameters to meet the improvement of structural material widely used in automobile, aerospace and marine applications. Result obtained from experimental analysis such that initial peak load, mean load, energy absorption and specific energy absorption versus displacement curves were compared for each specimen. Results showed that the tubes energy absorption was affected significantly by different tube profile. It is also found that the polymeric foam-filled exhibit superb crashworthy structure on specific absorbed energy and the amount of initial peak load, mean load and absorbed energy recorded higher than the empty tube profiles.


2020 ◽  
pp. 109963622097516
Author(s):  
M Safarabadi ◽  
M Haghighi-Yazdi ◽  
MA Sorkhi ◽  
A Yousefi

Honeycomb sandwich panels are widely used in marine, aerospace, automotive and shipbuilding industries. High strength to weight and excellent energy absorption are features that make these structures unique. Foam filling the honeycomb core enhances the mechanical properties of sandwich panels considerably. In the present study, the buckling behavior of Nomex honeycomb core/glass-epoxy face sheet sandwich panel for both bare and foam-filled honeycomb core is investigated numerically and experimentally, considering the viscoelastic properties of the sandwich panel. Indeed, the viscoelastic properties of the composite face sheet and foam are determined by relaxation test and are implemented in ABAQUS using VUmat code. The finite element method is also performed using ABAQUS to model the buckling behavior of the sandwich panel incorporating both elastic and viscoelastic material behaviour. The effects of composite face sheet lay-up, core thickness, core cell size, and foam filling are also evaluated. The experimental and numerical results show that the foam increases the critical buckling load and energy absorption.


Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1670
Author(s):  
Leilei Yan ◽  
Pengbo Su ◽  
Yagang Han ◽  
Bin Han

The design of lightweight sandwich structures with high specific strength and energy absorption capability is valuable for weight sensitive applications. A novel all-metallic foam-filled Y-shape cored sandwich panel was designed and fabricated by using aluminum foam as filling material to prevent core member buckling. Experimental and numerical investigation of out-of-plane compressive loading was carried out on aluminum foam-filled Y-shape sandwich panels to study their compressive properties as well as on empty panels for comparison. The results show that due to aluminum foam filling, the specific structural stiffness, strength, and energy absorption of the Y-shape cored sandwich panel increased noticeably. For the foam-filled panel, aluminum foam can supply sufficient lateral support to the corrugated core and vertical leg of the Y-shaped core and causes a much more complicated deformation mode, which cannot occur in the empty panel. The complicated deformation mode leads to an obvious coupling effect, with the stress–strain curve of the foam-filled panel much higher than those of the empty panel and aluminum foam, which were tested separately. Metallic foam filling is an effective method to increase the specific strength and energy absorption of sandwich structures with lattice cores, making it competitive in load carrying and energy absorption applications.


2011 ◽  
Vol 5 (1) ◽  
pp. 184-193 ◽  
Author(s):  
Levent Aktay ◽  
Cem Çakıroğlu ◽  
Mustafa Güden

The experimental and numerical quasi-static crushing behaviors of Nomex™ honeycomb-filled thin-walled Al tubes were investigated. The honeycomb filler was modeled using a unit cell model. The numerical model and experimental results have shown that, 6.4 mm and 4.8 mm cell size honeycomb filling had no effect on the deformation mode (diamond); however 3.2 mm cell size honeycomb filling changed the deformation mode to mixed/concertina. Honeycomb filling was also shown to increase the specific energy absorption of filled tubes over that of Al tube. The specific energy absorption of honeycomb filling was further compared with those of tube wall thickening and Al closedcell foam filling.


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