Metal Foam Research Articles

Blast mitigation using monolithic closed cell aluminium foam

Abstract Blast protection using cellular materials is being actively pursued at research and technology levels. The present work uniquely demonstrates the generation of stress waves, strain waves and mass velocities in monolithic closed cell aluminium foams of different densities and lengths subjected to simulated blast loads and their combined effect on blast attenuation. The foams were assumed to be resting against a rigid end wall. If the numerically calculated stress at the back face was less than the applied stress at the front face, the interaction was termed blast mitigation or attenuation. The results show that ‘pressure mitigation’ occurs for low-density foams whose plastic strength is less than the applied pressure, but pressure amplification for high-density foams whose plastic strength is higher than the applied pressure. The pressure amplification observed in shorter length high density foams transformed to pressure mitigation if the foams were sufficiently long. Based on these results and other stress, strain and velocity related diagnostics, the underlying mechanism behind blast wave amplification/mitigation and its relation with foam density and length is proposed.

Flexible Bridged Thermoelectric Device with an Optimized Heatsink for Personal Thermal Management.

A wearable thermoelectric cooler (TEC) for personal thermal management exhibits significant growth in numerous applications in personal thermal comfort and saving the energy consumed by space cooling. Most TECs provide a large cooling performance with the assistance of rigid heatsinks and electrodes, limiting wearability and practical implementation. Here, we design and propose a flexible bridged personal TEC with a high thermal management heatsink and spray-printed liquid metal electrodes. The system combines a bendable heatsink, a thermally insulative TE layer, and a bottom thermally conductive layer. Especially, the flexible heatsink composed of metal foam, phase change material, and fin structure greatly enhances the thermal conduction, storage, and diffusion capacities. Our TEC exhibits the desired comfortability and obtains an ideal temperature drop of 3 °C on human skin. Also, it could work as a self-generator providing 45 mV with a ΔT of 5 °C, which improves the generation efficiency by more than 3 times due to the stable temperature difference between the two sides. This work provides an effective way to develop wearable TEC devices and paves the way for achieving practical, personalized cooling applications.

Optimized design of energy absorption of aluminum foam filled CFRP thin-walled square tube based on agent model

PurposeAluminum foam-filled thin-walled unit structures have received much attention for their excellent energy absorption properties. To improve the energy absorption effect of car energy absorption box under axial compression, this paper optimizes the fiber lay-up sequence, fiber angle and aluminum foam density of aluminum foam filled carbon fiber reinforced plastic (CFRP) thin-walled square tubes.Design/methodology/approachDesign of sample points required to construct the proxy model using design of experiments (DOE) method, and the data sample points of different models are obtained through Abaqus simulation and test. A double high-precision proxy model with the maximum specific energy absorption (SEA) and the minimum initial peak crash force (PCF) as the evaluation index is constructed based on the response surface function method. The NSGA-II multi-objective genetic algorithm was used to optimize the design parameters and obtain the optimal solution for the Pareto front, and the results were verified by using the multi-objective optimization toolbox in design-expert.FindingsThe results show that the optimal solution to the multi-objective optimization problem with the inclusion of the lay-up sequence is ρ = 0.5g/cm3 for a fiber lay-up angle varying in the range ±15–90° and an aluminum foam density varying in the range 0.2g/cm3-0.5g/cm3, with a lay-up method of [±87°/±16°/±15°/±89°]. The two optimization methods correspond to SEA and PCF errors of 2.109% and 4.1828%, respectively. The optimized SEA value is 18.2 J/g and the PCF value is 18,230 N. The optimized design reduces the peak impact force and increases the specific energy absorption, which improves the energy absorption effect of thin-walled energy-absorbing boxes for automobiles.Originality/valueIn this paper, the impact resistance of CFRP thin-walled square tubes filled with aluminum foam is optimized. Based on numerical simulations and experiments to obtain the sample point data for constructing the dual-agent model, we investigate the effect of filling with different densities of aluminum foam under the simultaneous change of fiber lay-up angle and order on its mechanical properties in this process, and carry out the multi-objective optimization design with NSGA-II algorithm.

Design of continuously radial density-graded aluminum foam with unidirectional and bidirectional and study on blast resistance of sandwich tube

This work focuses on investigation of the internal blast resistance of metal sandwich tubes with continuously radial density-graded aluminum foam cores. Based on the 3D-Voronoi technology in polar coordinates, unidirectionally and bidirectionally continuously density-graded aluminum foam were developed for the cores of sandwich tubes in Finite Element (FE) model. And the correctness of core gradient was verified by comparing theoretical design with the actual value generated by FE model. Effects of core density distribution and core density gradient on blast resistance of sandwich tubes were explored and identified. The results indicate that, when the core density gradient is constant, the sandwich tube with negative-gradient core exhibits the smallest maximum deformation of the outer tube, while the negative-middle-low-gradient core tube shows the highest specific energy absorption ( SEA). For negative-gradient core tube, as the core density gradient increases, the maximum deformation of the outer tube decreases significantly, with only slight reduction of the structural SEA. For negative-middle-low-gradient core tube, as the core density gradient increases, the maximum deformation of the outer tube decreases, while the SEA increases.

Experimental and numerical studies on corrosion-resistant aluminium foam sandwich panel subject to low-velocity impact

Aluminium foam sandwich panels (AFSPs) have a high impact resistance and are suitable for a wide range of engineering applications. To improve corrosion resistance, this paper proposes an anti-corrosion sandwich panel with stainless steel as the upper sheet. Drop hammer impact tests were performed on a total of ten AFSPs to investigate their dynamic response and failure patterns. To assess the deformation performance of AFSPs, a laser displacement meter was used to obtain the bottom centre displacement. The effects of the impact energy and the thickness of each component of AFSPs on the peak impact force and deformation performance were studied. Test results showed that the thickness of each component had notable effects on the impactor and bottom displacements. In addition, the effect of the unit mass of the components in AFSPs on decreasing the bottom displacement was discussed. Compared to increasing the aluminium foam and lower sheet thicknesses, increasing the upper sheet thickness was more effective in decreasing the bottom displacement. A finite element model of AFSPs was developed to conduct parameter analysis, indicating that impactors with larger diameters resulted in higher peak forces and reduced deformation of AFSPs.

Modelling and optimization of experimental parameters for porosity in friction stir processed aluminum foam using response surface methodology

ABSTRACT Aluminium foams are an emerging multifunctional material with a distinct structure and unique properties. However, controlling the porosity and pore morphology is still challenging because of the dependency on a number of the process parameters. This study uses a statistical approach to control porosity and influence of each parameter on porosity in a friction-stir processed aluminium plate. A second-order Response Surface Methodology (RSM) model is developed, and relationship among porosity and process parameters like Weight % TiH2, Weight % Al2O3, number of passes, tool rpm, and foaming temperature has been established and influence of each parameter on porosity is investigated. Experimental results validate the model, optimising 80–85% porosity for multifunctional applications. The optimal parameters are 1.2 wt% TiH2, 2.3 wt% Al2O3, 3 passes, 3000 tool rpm, and 738 °C foaming temperature. It was observed from the ANOVA that most influencing parameter is tool rpm, number of passes, followed by foaming temperature. The Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS) analyses of the fabricated foam at its optimised condition confirm the uniform distribution of pores and the elements. This statistical optimisation model minimises experimental time and resource usage, demonstrating substantial technical and industrial significance.

Thermal uniformity analysis of a hybrid battery pack using integrated phase change material, metal foam, and counterflow minichannels

This study investigates the thermal performance and temperature uniformity of a hybrid battery thermal management system (BTMS) that integrates phase change material (PCM), metal foam, and minichannels. Computational fluid dynamics is used to model the PCM melting process and heat transfer between all components. The primary goal of the work is to investigate BTMS architectures which can enhance thermal uniformity and prevent critical temperature rise in a high-voltage battery pack under fast discharging and real-world driving cycle. Four BTMS designs are compared. The design that integrates PCM, metal foam, and counterflow minichannels is shown to have the best performance. At low pumping power (coolant Reynolds number Re = 10), this design reduces the peak battery temperature by 11.5 K compared to a design employing pure PCM only. This configuration also ensures a temperature difference of less than 5 K among individual battery cells, addressing thermal safety considerations and extending battery lifespan. Further analysis revealed that the inclusion of metal foam delays PCM melting, enhances both system and battery thermal uniformity, and offers a higher performance-to-weight ratio compared to designs without metal foam. Although wavy-shaped minichannels offer minimal temperature improvement (0.3 K) over straight minichannels, their higher cost and increased pumping power requirements do not justify their practicality. Under both fast discharging and real driving conditions, the first design with pure PCM provides uniform heat distribution within batteries but fails to maintain the maximum battery temperature within the optimal range. Overall, this study highlights the effectiveness of the proposed hybrid BTMS design in providing uniform temperature distribution and maintaining the maximum battery temperature within the optimal range under harsh environmental conditions, fast discharging, and the Urban Dynamometer Driving Schedule (UDDS) drive cycle.

Multi-objective optimization of metal foam parameters for enhanced performance of LHTES unit in shell-and-tube configurations

Latent heat thermal energy storage (LHTES) units utilize phase change materials (PCMs) to effectively store thermal energy and address the challenges of solar energy intermittency and instability. Heat transfer characteristics largely influence the thermofluidic efficiency of the LHTES unit during phase transitions. To improve the typically low heat transfer capabilities of PCMs, high-conductivity metal foams are introduced to enhance bulk heat conduction. This study focuses on optimizing the parameters of composite PCM (CPCM) embedded in the LHTES unit, specifically examining metal foam height (H), angle (θ), and porosity (ϵ), primarily affecting the performance of the CPCM. A series of Taguchi-based orthogonal experiments were conducted to analyze the effects of these variables. The results indicate that metal foam height has a notable influence on the CPCM performance, significantly reducing melt fraction variations caused by changes in cross-sectional geometry. ANOVA analysis shows that the metal foam height contributes 49.02% to improve operational time and 73.62% to enhance melt fraction. The study also identifies the optimal values for the metal foam parameters (H, θ, ϵ) that most effectively improve the LHTES unit thermal performance. Based on various indices, an economic assessment of the optimal configuration further supports the proposed design. Overall, the findings provide a recommended configuration to enhance the LHTES unit performance, contributing valuable insights for developing efficient TES systems and supporting sustainable energy management.

Reliability-based structural-thermal topology optimization of lightweight metal foam skeleton microstructure using the fully analytical adjoint method

Reliability-based structural-thermal topology optimization of lightweight metal foam skeleton microstructure using the fully analytical adjoint method

Recycling the Spent Lithium-ion Battery into Nanocubes Cobalt Oxide Supercapacitor Electrode

Background:: Cobalt oxide nanocubes have garnered significant attention as potential supercapacitor electrodes due to their unique structural and electrochemical properties. The spent lithium-ion batteries (LiBs) are considered as zero-cost source for cobalt oxide production. Objective:: The aim of this work is to recover cobalt oxide from spent LiBs and study its electrochemical performance as a supercapacitor electrode material. Method:: This study uses an electrodeposition method to obtain cobalt oxide honeycomb-like anodes coated on Ni foam substrates from spent Li-ion batteries for supercapacitors applications. The effect of annealing temperature on the cobalt oxide anode has been carefully investigated; 450 ºC annealing temperature results in nanocubes on the surface of the cobalt oxide electrode. X-ray diffraction confirmed the formation of the Co3O4-NiO electrode. Results:: The Co3O4-NiO nanocubes electrode has shown a high specific capacitance of 1400 F g-1 at 1 A g-1 and high capacitance retention of ~96 % after 2250 cycles at a constant current density of 10 A g-1 compared to 900 F g-1 at 1 A g-1 as for prepared Co3O4 honeycomb. Conclusion:: This strategy proves that the paramount importance of Co3O4-NiO nanocubes, meticulously synthesized at elevated temperatures, as a supremely effective active material upon deposition onto transition metal foam current collectors, establishing their indispensability for supercapacitor applications.

High temperature in-situ 3D monitor of microstructure evolution and heat transfer performance of metal foam

High temperature in-situ 3D monitor of microstructure evolution and heat transfer performance of metal foam

A 3D Model of a Photovoltaic Thermal Panel with the Heat Transfer Fluid Tube Embedded in a Layer of Phase Change Material and Metal Foam

A 3D Model of a Photovoltaic Thermal Panel with the Heat Transfer Fluid Tube Embedded in a Layer of Phase Change Material and Metal Foam

Investigating Thermal Control Methods for Lithium-Based Batteries Utilizing Metal Foams Saturated with Air

Investigating Thermal Control Methods for Lithium-Based Batteries Utilizing Metal Foams Saturated with Air

Pressure Drop in a Metal Foam Centrifugal Breather: A Simulation Approach

One of the main issues faced in the operation of a metal foam centrifugal breather is the high pressure drop. This study investigates the pressure drop of a metal foam centrifugal breather. The numerical simulation research method is adopted. The DPM model is used to calculate the two-phase flow field of the metal foam breather, and the porous medium model is used to replace the metal foam at the breather. The resistance caused by the metal foam is replaced by a distributed resistance added to the fluid. The effects of flow rate, rotational speed, porosity, PPI (pores per inch), and temperature on the pressure drop of the breather are analyzed. The results indicate that rotational speed, flow rate, porosity, and PPI significantly influence the resistance of the metal foam centrifugal breather. The resistance of the breather is directly proportional to the rotational speed, flow rate, temperature, and metal foam pore density, and inversely proportional to the porosity. Temperature has a minor impact on the resistance of the metal foam centrifugal breather. Therefore, the metal foam centrifugal breather is more suitable for low-speed operating conditions.

MICROSTRUCTURE AND WEAR BEHAVIOR CHARACTERIZATION OF STIR-CAST ALUMINUM 6063 ALLOY AND ITS FOAM: A COMPARATIVE STUDY

In this research work, aluminum 6063 alloy foam was synthesized through stir casting using varying amounts of titanium hydride as a foaming agent. A comparative microstructural and wear behavior analysis of stir-cast aluminum 6063 alloy and its foam is presented. The oxide and aluminide phases present as intermetallic compounds in the stir-cast aluminum 6063 alloy foam ensure the stability of the synthesized foam. In order to optimize the effect of wear parameters on the tribological properties of stir-cast aluminum 6063 alloy foam, the L933 orthogonal array (OA) was designed and modeled statistically. The tribological properties of stir-cast aluminum 6063 alloy and its foam were evaluated by pin-on-disc tests. The optimal tribological properties of the synthesized foam are 0.29 coefficient of friction, 8.6 N frictional force, and 0.00025 mm3/N-m specific wear rate. The tribological properties of stir-cast aluminum 6063 alloy foam are superior to those of aluminum 6063 alloy and comparable to other aluminum foams described in the literature.

Enhancing melt foam stability, form-filling process, and pore structure evolution of shaped aluminum foam

This study explores the stability of Al–Si–Ca–Mg-Sc melt foams and investigates the melt foam filling process and the dynamic evolution of pore structures in the fabrication of foam aluminum profiles using the melt transfer foaming technique. The results show that Al–Si–Ca–Mg-Sc melt foam maintains high porosity and a stable pore structure even after 30 min of foaming, without any signs of boundary rupture or destabilization. This stability is attributed to the increased viscosity from finely dispersed second-phase particles, which hinder the growth, coalescence, and drainage of the melt foam. Regarding melt foam filling, enhanced filling capability is achieved by elevating the foaming temperature, extending the foaming time, and increasing the TiH2 addition. The melt foam exhibits a smooth flow from the lower part of the mold to the corners, completing the filling process with well-defined edges in the profile. During lateral movement for filling, a gradual increase in porosity, a decrease in pore number, and a slow enlargement of pore size and standard deviation along the lateral (x-axis) are observed. This is due to the slower liquid phase flow compared to the gas phase, resulting in bubble coalescence. After filling is complete, this phenomenon improves, contributing to a slow and stable evolution of the pore structure.Under optimized conditions of 1.4 wt% TiH2 addition at 600°Cfor 9 min of foaming with Al–Si–Ca–Mg-Sc alloy melting, we successfully fabricated foam aluminum profiles with complete filling, a porosity of 81.5%, an average pore size of 2–3 mm, and a uniform pore structure.

Performance optimization of hydrogen storage reactors based on PCM coupled with heat transfer fins or metal foams

Metal hydride is a type of solid hydrogen storage material that offers excellent hydrogen absorption and desorption reaction properties. However, there is a strong thermal effect during the reaction process when the materials are applied in reactors. Thus, effective thermal management techniques are crucial for promoting efficient reactions. Prior studies on the subject have shown that phase change materials can be coupled with metal hydride reactors to transfer the reaction heat. To further enhance the transfer of heat and reaction efficiency of the metal hydride reactors based on phase change materials, this study explored heat transfer enhancement methods on the phase change materials side, including adding heat transfer fins and discussing the fin parameters and composite foam metal. The findings of the study showed that in comparison to the reactor without fins, the absorption rate of adding 10 sets of fins can increase by 28%, and as the number of fins increased to 14, this value could increase to 39.4%. The use of Y-shaped fins did not substantially improve the reaction rate, mainly due to the sufficient number of straight fins, and the heat transfer area reaching the limit of the fin enhanced the process of heat transport. Thus, the improved method of using copper foam is further considered. Compared with the reactor with and without fins, the absorption rate of the copper foam coupled reactor is increased by 23.4% and 61.3%, respectively.

Impact behavior of the SCS panel with hybrid energy absorbing components: Experimental and analytical studies

A new steel-concrete-steel panel with front aluminum foam layer and rear energy absorbing connector (SCS-FL-EAC) was firstly developed. The dynamic behavior of SCS-FL-EAC was studied through conducting drop-weight impact tests. Three stages of impact process of SCS-FL-EAC were identified. The aluminum foam layer and energy absorbing connector were crushed under impact loading. The aluminum foam layer reached densification, and a local indention was observed beneath the projectile. Plastic hinges were also found at the corners of the pleated steel plate of the energy absorbing connector. The SCS panel exhibited the combination of bi-linear global flexural deformation and local deformation. Furthermore, the effects of aluminum foam layer on the impact resistant performances of SCS-FL-EAC were investigated. The results indicated that the inclusion of the aluminum foam layer effectively mitigated inertial effects and reduced the maximum impact force. Additionally, the SCS-FL-EAC demonstrated improved impact-resistant performances with an increased thickness of the aluminum foam layer. Furthermore, an analytical model was proposed to predict the force and displacement responses of SCS-FL-EAC subjected to impact load, and the predicted impact responses showed good agreement with experimental results.

Design and preparation of composite bipolar plates with synergistic conductive networks of graphite and metal foam

Graphite composite bipolar plate (BP) have limited conductivity, which makes them less than ideal for extensive application in proton exchange membrane fuel cell (PEMFC). In traditional graphite composite BP, the construction process of the conductive network is entirely random. To enhance conductivity, it is typically necessary to increase the content of conductive fillers or incorporate high aspect ratio carbon nanomaterials to optimize the density of the conductive network. In this work, we manufactured a highly conductive composite bipolar plate with synergistic conductive networks of graphite and metal foam (MF). With a synergistic conductive network, the ASR of CuG80-20ppi decreased to 7.7 mΩ cm2. Additionally, thermal conductivity increased to 24.76 W/(m·K), and in-plane conductivity reached 294.1 S/cm at 80 wt% mass fractions of conductive filler, using 20 ppi copper foam as the metallic conductive network. CuG80-20ppi exhibited a flexural strength of 52.2 MPa. G80 and CuG80-20ppi have the 80 wt% conductive filler and are molded into BP with parallel flow fields. CuG80-20ppi enhances the current density of PEMFC by 0.132 W/cm2 and reduces the ohmic impedance by 5.25%. Therefore, the findings of this study offer valuable insights for the enhancement of composite BP conductivity, while simultaneously ensuring the stability and continuity of the synergistic conductive network. A novel approach is presented to enhance the electrical conductivity of graphite composite bipolar plate (BP) for proton exchange membrane fuel cells (PEMFCs). By embedding metal foam as a supplementary conductive network within the graphite matrix, a synergistic conductive architecture is achieved. This innovation significantly reduces the area specific resistance (ASR) to 7.7 mΩ cm2 and boosts thermal conductivity to 24.76 W/(m·K). The resulting CuG80-20ppi BP, with 80 wt% conductive filler, exhibits improved mechanical strength and conductivity, contributing to a 0.132 W/cm2 increase in PEMFC current density and a 5.25% reduction in ohmic impedance. This work highlights the potential of metal foam integration to enhance BP conductivity and PEMFC performance.

Liquid Metal-Based Elastomer Composite with Selective Switchable Adhesion to Solids.

Selective switchable adhesion has recently attracted much attention due to its wide applications in transfer printing, information transfer, and flexible electronics. However, selective adhesive materials often have a complex adhesion or preparation process, which limits their use. To overcome this problem, this study prepares a composite of liquid metal foam and polydimethylsiloxane (PDMS) with selective photocontrolled adhesion, which can directly adhere to solids at room temperature. Utilizing the photoinduced phase transition of liquid metals, solid adhesion can be regulated by changing the backing layer modulus of the adhesive layer. Since the phase transition process is gradually completed by heat transfer from the illuminated side to the backlight side that adheres to the solid, the melting area on the backlight side can be regulated by controlling the light time, which determines the adhesion regulation area. Therefore, the accuracy of the adhesion regulation can reach less than 0.9 mm without relying on the accuracy of the infrared light. Moreover, based on the selective switchable adhesion, the selective transfer of solids with different scales can be achieved at room temperature. The findings of this study may provide strategies for the simple preparation of selective adhesive materials and the improvement of control accuracy.