Foam-filled Tubes Research Articles

Analysis of factors influencing the energy absorption characteristics of gradient foam-filled thin-walled circular tubes with variable thickness and origami patterns

The use of variable thickness origami structures in automotive energy absorbers introduces a novel concept in the design of energy-absorbing systems. By filling these structures with gradient foam, the energy absorption properties of different materials can be fully leveraged to design more efficient structures. In this study, finite element simulations and quasi-static compression experiments were conducted to validate the energy absorption performance of 3D-printed origami-patterned thin-walled tubes. The impact of various factors, including the number of tube edges, layers, foam densities, and thickness variations, on the energy absorption characteristics was systematically analyzed and compared. The results show that the introduction of folds and gradient structures effectively enhances the energy absorption capacity of thin-walled tubes. The total energy absorption (EA) and specific energy absorption (SEA) of the positive gradient wall thickness tube (C4) were increased by 4.9% and 4.7%, respectively, compared to the negative gradient wall thickness tube (C1), while the initial peak force was reduced by 2%. Similarly, the EA, SEA, and CFE of the positive gradient polyurethane foam-filled tube (E1) were increased by 0.61%, 0.6%, and 4.3%, respectively, in comparison to the negative gradient foam-filled tube (E4), with the initial peak force (PCF) reduced by 3%. It is demonstrated that origami-patterned thin-walled tubes with gradient structures and internal gradient foam fillings possess excellent energy absorption characteristics. The findings of this study provide valuable reference points for the future structural optimization of gradient foam-filled thin-walled tubes with variable thickness and an origami pattern.

Analytical and numerical investigations of metal square origami foam-filled tube under axial compression

It is widely known that thin-walled structures are expected for numerous engineering devices, due to lightweight, high specific strength, and excellent energy absorption capacity. Thus, the new high-efficiency energy absorbing (EA) device is the eternal pursuit goal of designers. A novel high-efficiency energy-absorbing device of the metal square origami foam-filled tube (MSOFT) under axial compression is designed in this article, and axial crushing of the MSOFT is investigated analytically and numerically. An analytical model for axial crushing of MSOFT is established based on the conservation of energy and the hyper-folded unit theory, considering the energy absorbed by the deformation of metal origami tube, foam compression, and the interaction between foam and origami tube. Then, the finite element (FE) simulation of MSOFTs under axial compression are conducted by Abaqus/Explicit software, and found that theoretical results are in good consistency with the FE results. Then, the influences of yield strength, wall thickness, height and cross-section width of the tube, and foam strength of MSOFT under axial compression are discussed, and found that the force and energy increases when the above parameters increase. Finally, the mean crushing force (MCF) and the crushing force efficiency (CFE) among MSOFT, origami tube and square tube are compared. Compare with the origami tube and square tube, the MCF of MSOFT increases by 40.8–106.9% and 12.1–49.8%, and the CFE of MSOFT increases by 101.2–266.3% and 1.1–12.4%. It is indicated that for a wide range of geometric and material parameters the MSOFT exhibits predictable and stable collapse behavior.

A Novel Approach for Fabricating In Situ Aluminum Foam‐Filled Carbon Steel Tubes via Hot‐Dip Aluminizing

Herein, a new process combining hot‐dip aluminizing (HDA) technology with melt foaming method is developed to prepare in situ aluminum foam‐filled AISI 1020 tubes with metallurgical bonding which has the advantages of low production cost and wide range of product sizes. Detailed microstructural characterization is performed at the foam/tube interface of in situ foam‐filled tubes (FFTs). Quasistatic compressive experiments are carried out to investigate deformation behavior and mechanical properties of ex situ and in situ FFTs with and without HDA pretreatment (in situ‐HDA FFTs and in situ‐without HDA FFTs). The results indicate that HDA pretreatment effectively improves the wettability between the steel tube and the aluminum melt, enhancing the interfacial bonding quality between the two. Under compressive loading, in situ‐HDA FFTs axially deform in an efficient mixed mode, showing superior energy absorption capability as compared to the empty heat treatment (empty‐HT) tubes. Specifically, in situ‐HDA FFTs have the highest specific energy absorption of an average of 16.6 kJ kg−1 which is 13% higher than the average value of ex situ‐HT FFTs.

Compressive Properties of Aluminium Foam-Filled Square Stainless Steel Tubes With Elliptical and Circular Holes

Compressive Properties of Aluminium Foam-Filled Square Stainless Steel Tubes With Elliptical and Circular Holes

Coupled energy absorption effect and structural optimization of an aluminum foam-filled multi-cell thin-walled conical tube

Coupled energy absorption effect between the aluminum foam and the thin-walled tube plays a significant role in the crushing process. Firstly, a composite structure filled with aluminum foam in a multi-cell conical tube is proposed. Secondly, the influence of structure parameters on coupled energy absorption is investigated. Thirdly, the energy absorption mechanism is analyzed. Additionally, the structure is subjected to multi-objective optimization. The results show that increasing structure parameters are beneficial to coupled energy absorption effect. In addition, there are SEA = 26.18 J/g and F P =86.22 kN for the optimal tube, which is superior to most existing aluminum foam-filled tubes.

Crashworthiness design and enhanced energy absorption of multi-cell thin-walled circular tubes

In order to improve the crashworthiness and enhance the energy absorption capacity of thin-walled structures, a new multi-cell thin-walled circular tube was established by combining the advantages of type I (bending-dominant) and type II (tension-dominant) structures in this paper. The crush resistance and specific energy absorption (SEA) of multi-cell empty and multi-cell foam-filled tubes (MFTs) subjected to axial crushing loads were experimentally investigated. It was shown that due to the introduction of ribbed structures, the crush resistance and energy absorption efficiency of multi-cell empty tubes can be obviously enhanced. Filling the empty tube with foam, the peak force of foam filled thin-walled circular tube structure is improved distinctly. The MFTs have a higher crushing load efficiency and lower average loading fluctuation than the corresponding multi-cell empty tubes, which are mainly affected by the ribbed angles. With the increase in ribbed angles, the load-carrying capacity and the SEA of the MFTs can also be enhanced, but the undulation of the load-carrying capacity is simultaneously reduced. When the ribbed angle is more than 45°, the MFTs have better energy absorption and crushing load efficiency. Compared with a multi-cell empty tube, the SEA of the MFT increased by about 19%.

Characterization of the properties of arc-welded aluminum matrix syntactic foam-filled tubes

Abstract In this research, the authors aimed to manufacture and weld in-situ composite foam-filled tubes from expanded clay aggregate particles, AlSi12 aluminum matrix, and AlMgSi0.5 tubes using tungsten inert gas welding. Subsequently, the quality of the welded joints was examined after precipitation hardening heat treatment and without heat treatment, followed by the evaluation of the results. The welded joints were characterized by microstructural examinations, microhardness measurements, and hardness testing. It was found that the hardness of the tube can be increased with heat treatment after the welding by 23 % on average and that the heat input of the welding process causes silicon enrichment due to diffusion within the AlMgSi0.5 tube, which is accelerated by the heat treatment cycle.

Compression behavior of ex-situ PVC foam-filled tubes

Abstract The present work investigates the mechanical characteristics of tubes filled with Polyvinyl chloride (PVC) foam. The tubes used are made of aluminum and were filled ex-situ. Static compression tests were performed on both axially (AL) and laterally (LL) loaded tubes. Comparisons between foam-filled (FFT) and empty (ET) tubes are presented, highlighting the foam-tube interaction effect. The emphasis is on elastic, strength and strain properties, but energy absorption performances are not neglected. Discussions regarding the failure mechanisms of ETs and FFTs are also presented. It was obtained that, regardless of the loading direction, FFTs show clearly superior mechanical properties to ETs. At the same weight, the specimens tested axially support higher loads than those tested laterally. This aspect is due to deformation mechanisms that take place in the samples during the tests. It was noted that the compressive strength is more affected by the filling than by the compressive modulus. Under lateral loads, the ETs samples fail quasi-brittle through complete failure of the tube, while in the case of FFTs, a ductile fracture with stable deformation of the sample is obtained.

Modeling the deformation of thin-walled circular tubes filled with metallic foam under two lateral loading patterns

Thin-walled circular tubes with metallic foam fillers are widely used in various engineering fields. This work examines the plastic behavior of thin-walled circular tubes filled with metallic foam under two different lateral loading patterns, by using both analytical and numerical methods. Two types of loading indenters, including a line load and a rigid plane, are considered. There have been very few studies on the lateral compression of foam-filled circular tubes crushed by a line load or a rigid plane. The analytical models assume that the tubular wall material is rigid and ideally plastic, and that the metallic foam fillers maintain a constant resistance known as plateau stress. Using the principle of virtual velocities, we derive succinct explicit solutions for the crushing forces as well as deformation characteristics in regard with the radius of the tubes, the flow stress of the tubular wall and the plateau stress of the filled foam under the two loading conditions. Finite element analysis is performed using the ABAQUS2023/Explicit code to model aluminum alloy circular tubes filled with aluminum foam. A comparison and analysis of the deformation characteristics of the tubular top generator and foam cross-sections are conducted. The proposed analytical crushing forces and deformation properties obtained herein agree well with the numerical simulation results and outperform previous theoretical models, which may serve as valuable formulations for the engineering application.

TIG welding of in-situ produced syntactic metal foam-filled tubes

Abstract Aluminium matrix double composites were produced via an in-situ pressure infiltration method. AlSi12 alloy matrix with densely packed lightweight expanded clay aggregate particle-filled foam was produced in-situ within AlMgSi0.5 alloy tubes. The attainable size of such double composites is limited; therefore, joining them is required to create larger parts. For the joining of these double composites, the applicability of tungsten inert gas (TIG) welding was tested. TIG welding was found to be applicable to join such composites. Metallurgically sound welded joints were produced. Nevertheless, the TIG welding of metal foam-filled tubes is very challenging and needs experienced welding personnel, and the weld bead was a bulk material, not a foam anymore.

A novel efficient energy absorber: circular metal foam-filled tube under external inversion over a die

A novel efficient energy absorber: circular metal foam-filled tube under external inversion over a die

Crashworthiness analysis and multi-objective optimization design for foam-filled spiral tube

Thin-walled structures, due to their favorable mechanical properties and exceptional energy absorption capabilities, find extensive applications across various engineering fields. This study, drawing inspiration from natural spiral structures, introduces a novel foam-filled spiral tube (FFST) to further enhance the crashworthiness of thin-walled structures. The spiral tubes (STs) and random foam are additively manufactured. Quasi-static compression tests are undertaken to investigate the energy absorption properties of STs, foam and FFSTs. Unlike conventional methods, this study adopts micro-computed tomography (micro-CT) technology to understand the mechanisms of interaction between the foam and ST. The parametric study is performed based on the finite element model to evaluate the influence of meso‑structure properties of tubes and foam fillers on the crashworthiness and deformation modes. The experimental results indicate that an increase in the wall thickness of both the ST and foam leads to a simultaneous increase in specific energy absorption (SEA) and initial peak crushing force (IPCF). Conversely, a decrease in the wavelength and an increase in the amplitude of waves results in the reduction of both SEA and IPCF, along with an enhancement of crushing force efficiency (CFE). Micro-CT images indicate mutual extrusion between the foam and ST and with a reduction in wavelength, the number of folds in the samples increased, thus enhancing the energy-dissipation capacity. The numerical results reveal a strengthening of interaction between the foam and ST with decreasing wavelength and increasing foam cell wall thickness. A theoretical model is proposed for predicting the plateau stress of FFSTs based on the energy conservation principle and the plastic hinge theory. Comparisons between theoretical and test results exhibit good agreement. Comparing the FFST obtained through multi-objective optimization design with an ST featuring same structural parameters, it is observed that the IPCF increases by 8.00 %, SEA increases by 18.10 %, and the undulation of load-carrying capacity (ULC) decreases by 31.96 %. Finally, through a comparative analysis with other energy-absorbing structures, the outstanding performance of this structure is established. This study offers a new approach for investigating interaction effects and provides useful guidelines for the design of future high-performance light-weight materials and structures.

Novel interaction effects enhance specific energy absorption in foam-filled CFRP tapered tubes

This study unveils a novel interaction effect in the foam-filled CFRP tapered tubes that enhances their specific energy absorption (SEA), challenging the conventional understanding that foam fillers decrease the SEA of structures like foam-filled CFRP straight tubes and foam-filled metal tapered tubes. Quasi-static axial compression tests were conducted on foam-filled CFRP tubes with varying taper angles (0°, 5°, 10°, 15°) to confirm and quantify this newfound interaction effect. The energy absorption characteristics and interaction effect due to the foam filler in the foam-filled CFRP tapered tubes were thoroughly evaluated and compared to 3D-printed 316L stainless steel tubes and unfilled CFRP counterparts. Contrary to expectations, our results indicate that the foam-filled CFRP tubes consistently outperform both steel and unfilled CFRP tubes in energy absorption. Intriguingly, the CFRP foam-filled tapered tubes in this study demonstrated higher SEA compared to CFRP tubes without foam filler, underscoring the remarkable effectiveness of CFRP materials in foam-filled tapered tube applications. Our comprehensive interaction effect analysis highlights the substantial contribution of the unique synergy between the foam filler and the debris of the CFRP tapered tube to this increased SEA. Additionally, we propose a novel hybrid design that integrates straight and tapered CFRP tubes with foam fillers, leveraging the newfound interaction effect to further enhance the energy absorption of tapered tubes. This research not only emphasizes the advantages of foam fillers in enhancing CFRP tapered structures but also introduces innovative possibilities for energy absorption applications across various industries.

Investigation and optimization of energy absorption performance of axially joined metal and composite foam-filled hybrid tubes

Investigation and optimization of energy absorption performance of axially joined metal and composite foam-filled hybrid tubes

Experimental and numerical study on the energy absorption performance of aluminum foam-filled multi-cell square tubes

When rockbursts occur, the unloading rate of the relief valve of the hydraulic support is less than the loading rate of the impact load, which leads to a continuous increase in the hydraulic column pressure or even failure. To improve the service life of hydraulic support structures under impact loading, an aluminum foam-filled multi-cell square tube is designed and investigated as an energy absorption component to prevent support column failure. In this study, the energy absorption performance of the multi-cell square tube during buckling deformation is investigated via simulation and quasi-static compression tests considering the cross-sectional shape and aluminum foam filling rate. The equivalent crushing load of the tube is calculated by analyzing the impact of the basic deformation unit. The results show that the corner-to-corner (C2C) multi-cell square tube exhibits the best energy absorption performance among six kinds of cross sections. In addition, the interaction between aluminum foam and a multi-cell square tube can improve the performance of the multi-cell square tube. Furthermore, after the C2C component is installed in the support column, the load on the column is significantly reduced, and most of the impact energy is absorbed. These results are expected to improve the performance of hydraulic supports and can be used to prevent rockbursts, which is highly important for practical engineering.

Experimental and numerical study on the impact response of the steel-concrete-steel-foam-filled-tube energy absorbing structure

A novel energy absorbing structure is proposed and can be fixed on the front of protected structures to reduce the impact-induced damage. This energy absorbing structure consists of nine polyurethane foam-filled steel tubes (PUFFSTs) and a steel-concrete-steel sandwich panel (SCSSP) and is named steel-concrete-steel-foam-filled-tube energy absorbing structure (SSEAS). The present study investigates the energy dissipation characteristics and dynamic responses of SSEAS through both experimental and numerical analyses. All specimens exhibited the same failure mode, including the collapse of the centre PUFFST and the local indentation of the SCSSP. The investigated parameters contain the thickness and width of the steel tube, thickness of concrete core and the initial momentum of the drop weight. A comprehensive discussion is presented on the impact response and energy dissipation performance. The results indicate that the thinner concrete core would result in larger deformation but shallower local indentation. Additionally, raising the width and thickness of the steel tube would result in higher energy absorbing capacity and larger proportion of energy dissipation of PUFFSTs. The numerical studies also show that higher initial momentum of the drop weight would induce a longer duration and larger energy dissipation of PUFFSTs.

Crashworthiness analysis of empty and foam-filled circular tubes with functionally graded thickness

Crashworthiness analysis of empty and foam-filled circular tubes with functionally graded thickness

Numerical crashworthiness analysis of 2014 Aluminium-Silicon Carbide Particle (SiCp) foam filled Carbon Fiber-Reinforced Plastic (CFRP) tube under impact loading

Aluminium foam and Carbon Fiber Reinforced Plastic (CFRP) are widely used composite materials in automobile industries due to the benefits of lightweight and energy absorption capacity. Therefore, in this study, the numerical crashworthiness analysis of 2014 Aluminium-SiCp (2014AA-SiCp) foam filled in CFRP tube has been performed under impact loading. Quasi-static compression tests have been conducted on 2014AA-SiCp foam to extract the mechanical parameters required for numerical simulations. To understand the crushing behavior under the axial impact loading, 2014AA-SiCp foam-filled CFRP tube has been numerically modelled using ABAQUS® software. The parametric study was carried out to explore the effects of filler material, foam densities, and impact velocities on crushing behavior. It was found that load increases with the rise in foam density and impact velocity. Moreover, the deformation increases with the increase in impact velocity. Results showed that the load carrying capacity of foam filled CFRP tubes was significantly improved compared to that of empty CFRP tubes. The foam filled CFRP specimens exhibited peak load of 122 kN and an energy absorption capacity of 3012 J, showcasing an approximate improvement of 43% and 11% respectively, over the values obtained for empty CFRP tubes.

Elastic-plastic response for the foam-filled sandwich circular tube under internal blast loading

The dynamic response and the blast resistance of an aluminum foam-filled sandwich circular tube under internal blast loading was investigated theoretically. The deformation of the structure is decoupled into three phases corresponding to blast loading interacting with the internal tube, foam core crushing and external tube deformation. During the process, the theoretical model includes both the circumferential membrane forces and the axial moment components and considers an elastic-plastic strengthening model for internal/external tubes. The proposed model is tested against the experimental results for the mid-point deflection of the external/internal tubes. The influence of the physical and geometrical parameters of the structure on their deformation is investigated. It is shown that the dimensionless mid-point deflection of the external tube decreases as the tangent modulus of the internal/external tube increases, while the tangent modulus of the internal tube has a larger effect on the mid-point deflection of the external tube. The minimum mass of a sandwich circular tube can be found when the deformation of the external tube is specified. The research results can provide theoretical basis for lightweight structure design.

Design optimization of the bamboo-inspired foam-filled tube for high-speed train collision energy absorption

This study first developed a novel bamboo-inspired foam-filled tube (BFFT) for potential application in high-speed trains, considering the practical use conditions. The BFFT was initially designed by mimicking the macro and micro characteristics of bamboo culms and understanding their axial crushing mechanical behavior. The key bionic parameters are drawn based on the crashworthiness indices of natural bamboos with various geometric sizes and growth ages. The numerical simulation model of the BFFT under axial impact load was established and verified using simplified super folding element (SSFE) theory and drop-weight experiments. A multi-objective optimization on the BFFT was conducted to find the optimal parameter alternative, integrating experimental design method of the optimal Latin hypercube, the response surface agent model and the non-dominated sorting genetic algorithm (NSGA-II). The crashworthiness performance of the optimized BFFT was compared with the initial design scheme, a conventional circular tube and other existing energy absorbers of rail vehicles. The results indicated that the EA, SEA and IPCF values of the optimized BFFT can be improved by 150.2 %, 63.3 %, and 48.5 %, respectively, when considering the single target requirement. In comparison to the initial design scheme and conventional circular tube, the SEA value of the final optimized BFFT increased by 44.7 % and 53.0 %, respectively. The proposed novel BFFT demonstrated a superior crashworthiness, providing inspiration for enhancing and optimizing passive safety performance of high-speed trains.