Metal Foam Research Articles

Experimental and numerical study on seismic performance of aluminum foam infilled steel frame-braced structural system

Experimental and numerical study on seismic performance of aluminum foam infilled steel frame-braced structural system

Mesoporous Metal Sponges Produced by Explosive Decomposition.

The formation of mesoporous gold sponges by explosive decomposition of 'knallgold' (also known as 'fulminating' gold) is studied. Proof-of-principle experiments are conducted and then the phenomena are further investigated using 'toy physics' molecular dynamics simulations. The simulations invoked various ratios of a volatile Lennard-Jones element G and a noble metal element N. In both experiment and simulation the morphology of the resulting sponge is found to depend on the stoichiometry of the starting material. As the mole fraction of G (χG) is increased from 0.5 to close to 1.0 in the simulations, the morphology of the sponges changes from closed to open, with a corresponding increase in the average mean curvature from 0 to +0.12 inverse Lennard-Jones length (L) units. The average Gaussian curvature of the simulated sponges is always negative, with the minimum value of 0.05 L-2 being found for χG≈0.65. In broad agreement with experiment, sponge formation in the simulations is bounded by stoichiometry; no sponges form if χG is <0.52, for χG between 0.52 and 0.70 the sponge is characterized by vermicular cavities whereas classic bicontinuous fibrous sponges form for 0.70<χG<0.85 and, finally, discrete particles result if χG>0.85.

Simulation and experimental study of thermoelectric generators with an axial gradient metal foam heat exchanger

The utilization of metal foam for heat transfer augmentation is regarded as a highly efficient technique, albeit associated with significant pressure losses. To enhance the feasibility of employing metal foam in thermoelectric generators and mitigate the high-pressure drop, we propose an enhancement strategy involving the partial axial filling of gradient metal foam. Both analytical modeling and experimental investigation were employed to evaluate the effects of porosity, pore density, and gradient structure at various filling rates on the overall performance of thermoelectric generators. The results show that arranging metal foam with increasingly high frame density in the direction of fluid flow, rather than adopting increasingly sparse or constant structures, leads to improved voltage uniformity and reduced pressure drop. A positive gradient configuration with a pore density distribution of 5-10-20 PPI yielded the highest net power at 118.3 W, which is 12.5 % higher than that of metal foam with constant 20 PPI. Ultimately, empirical verification substantiates the comprehensive performance advantages of positive gradient configuration. For filling rates of 30 %, 60 %, and 100 %, pressure drop is reduced by 35.9 %, 33.4 %, and 29.2 %, respectively, in comparison to constant 20 PPI metal foam, despite a modest reduction in output power, which remains less than 3 %.

Phase change heat storage and enhanced heat transfer based on metal foam under unsteady rotation conditions

Phase change heat storage technology is an essential method for balancing supply and demand in solar energy heat utilization. In this study, a numerical model of the phase change heat storage process is built to explore the impact of non-constant rotation, with and without metal foam. Subsequently, an investigation into the influence of metal foam pore density and porosity on heat storage performance is conducted, with a focus on Taguchi design for statistical analysis. The research delves into the effects of foam parameters on heat storage rate, temperature response, heat storage time, and heat storage properties. Findings reveal significant resolidification in the melting process of this thermal storage structure without metal foam, due to periodic rotation speed hindrance in transferring heat to the outside. Taguchi design results underscore the greater influence of porosity on the melting time and average heat storage rate compared to pore density. Specifically, a reduction in melting time by 62.21 % and 30.49 %, and an increase in average heat storage rate by 237.56 % and 51.19 % is observed when pore density and porosity are 40 PPI and 0.97, compared with the ones with porosities of 0.99 and 0.98, demonstrating minimal impact on total heat absorption.

Anti-penetration properties of negative Poisson’s ratio honeycomb sandwich structure filled with foam

The ballistic responses of negative Poisson’s ratio honeycomb sandwich structures filled with aluminum foam are investigated using numerical simulation method. The residual velocity of the projectile, the energy absorption, and the failure forms of the sandwich structures are systematically analyzed. The influence of the impact position and incidence angle of the projectile, wall thickness, and concave angle of honeycomb, as well as the thickness of the front and back sheets of the structure on the penetration resistance is discussed. The results show that the foam-filled honeycomb sandwich structure has a better penetration resistance than the foam core sandwich structure with the same areal density, and the penetration resistance of the foam-filled honeycomb sandwich structure can be improved by designing its geometric parameters.

A molecular dynamics study on pore structure: Performance comparison between metal foam and artificial mesh porous surface

With the development of surface engineering, porous surfaces have emerged as a significant research subject in boiling heat transfer. The latter, in turn, plays a crucial role in various industries such as power plants, distillation plants, and microelectronic technology. In this paper, the Molecular Dynamics method is adopted to investigate the wicking dynamics and boiling dynamics of two porous surfaces: foam, which exhibits randomly distributed pores, and mesh, composed of ordered square wires with relatively uniform pore sizes. Three wettability, namely hydrophilic, neutral, and hydrophobic wetting states, are assigned to the two porous surfaces de-coupling the effect of wettability from surface structure. Results reveal that, during the wicking process, the foam surface shows better wetting ability as it absorbs liquid under both hydrophilic and neutral wettability. Comparatively, the mesh surface has the fastest wicking speed under hydrophilic wettability yet it becomes non-wetting under neutral wettability. During the boiling process, the boiling dynamics differ greatly under three wettability. More importantly, the difference in surface structure makes the foam surface possess a better heat transfer whereas the mesh surface causes gentle pressure variation. Our findings provide insights into the design of artificial porous surfaces for certain purpose and their potential application.

Energy absorption of foam-filled TPMS-based tubular lattice structures subjected to quasi-static lateral crushing

Aluminium foam and TPMS-based tubular lattice structures (T-TLS) were of interest due to their superior energy absorption capabilities and inherent lightweight characteristics. However, their synergistic functionality in a composite form remained unexplored. In pursuit of augmenting the crashworthiness characteristics, aluminum foam was filled into T-TLS to form foam-filled T-TLS. FE models were established and validated using lateral crushing experiments. Foam-filled T-TLS exhibited higher energy absorption (EA) compared to the sum of empty T-TLS and foam filler, primarily attributed to the interaction between T-TLS and foam filler. Compared to single circular filled tubes (SCFT) with the same outer sizes and mass, foam-filled T-TLS revealed markedly enhanced crashworthiness, with EA and SEA values being 3.5–3.9 times and 4.0–4.7 times that of SCFT, respectively. Subsequently, parametric investigations underscored the evident influences of relative densities of T-TLS and foam filler, tube thickness and diameter on crashworthiness of foam-filled T-TLS. Finally, a multi-objective optimization was performed to derive optimized configurations by using non-dominated sorting genetic algorithm II (NSGA-II) and radial basis function (RBF) metamodels. In comparison with the baseline designs, the optimal results demonstrated significant enhancements in crashworthiness, with SEA increasing by 173.3 to 206.6 %. The present work provided a new paradigm in the design and development of advanced energy absorbers characterized by high-efficiency energy dissipation under lateral impact scenarios.

Study on the flow and heat transfer characteristics inside high-porosity open-cell copper foams: Experimental and numerical explorations

A metal foam with an open-cell structure is a type of material with low flow resistance, high specific surface area, and strong fluid mixing ability. Open-cell metal foams have broad application prospects in electronic component cooling, multiphase heat exchangers, and compact heat exchangers for aerospace applications. This paper presented experimental and numerical analyses of the flow and heat transfer characteristics of five different copper foams under forced air convection. The pores per inch (PPI) of selected foams were 10, 20, 30, 40, and 60, with porosities ranging from 0.968 to 0.973. Analysis of the collected heat transfer and pressure drop data yielded the overall heat transfer coefficient, unit pressure drop, normalized average wall temperature, inertia coefficient, and resistance coefficient. The influence mechanisms of the porosity and flow velocity on heat transfer were analyzed and discussed. The numerical simulation and experiment fitted well. The results showed that increasing porosity led to a significant increase in heat transfer coefficient and unit pressure drop. The 60 PPI foam brought the maximum pressure drop while achieved the minimum thermal resistance.

Mathematical Solution for Vibrational Response of Shear and Normal Deformable Advanced Metal Foam CMBS Treated with Nanocomposite Actuators

This research focuses on examining the vibrational properties of intelligent curved microbeams (CMBs) that incorporate metal foams and are enhanced with carbon nanotubes-reinforced piezoelectric (CNTRP) actuators. An advanced four-variable theory for shear and normal deformation is applied in the polar coordinate framework to investigate the microstructure, thereby negating the need for a shear correction factor. Additionally, the modified couple stress theory (MCST) is utilized to account for scale effects. The structural attributes exhibit thickness-dependent alterations following predefined functions. The governing equations of motion are deduced using Hamilton’s principle. In instances where the structure has simply supported ends, Fourier series functions are utilized to solve these equations. The outcomes are cross-validated in contradiction with previously documented works with more straightforward setups. The inquiry investigates the effects of critical parameters on the vibrational response of the structure. The results are corroborated in simpler scenarios using existing data in the literature to ensure accuracy.

A review on thermal energy storage with phase change materials enhanced by metal foams

Due to the mismatch between energy demand and energy production, in the last years the study of latent thermal energy storage systems has been significantly growing. This work aims to provide an overview of the studies and the experiments carried out on thermal energy storage systems, that use phase change materials combined with metal foams. A histogram that shows how the number of works on these subjects has been increasing over the years is reported; consequently, a general survey on phase change materials is conducted, identifying the temperature ranges and the latent heat which are most used in thermal energy storage systems and defining the strengths and weaknesses of the various types of phase change materials. Furthermore, the paper illustrates the models and methods currently used to describe the phase transition of phase change materials in metal foams. Subsequently, how metal foams improve the desirable characteristics of phase change materials is described, and then it is represented in what percentage the different pore sizes (PPI) are used and what the most functional porosity is for individual works. Lastly, through the summary of the analyzed papers some specific articles are considered, in order to explain the state-of-the-art and to clarify some fundamental concepts.

Preparation and mechanical properties of in-situ aluminum foam-filled SS304 corrugated tubes with metallurgical bonding

In this work, AlSi10Ca3Mg0.5 alloy foam-filled SS304 corrugated tubes (FFCTs) were prepared by melt route with surface modification of the tube substrate prior to in-situ foam filling. Results showed that successful metallurgical bonding can be achieved between aluminum foam and the tube with surface modification. Under quasi-static axial loading, the foam core within FFCTs were compressed densely from top to bottom in sequence, showing an axisymmetric deformation mode. Due to the enhanced bonding between the foam and the tube, FFCTs with surface modification demonstrated approximately ∼19 % increase in specific energy absorption compared to FFCTs without surface modification.

Lattice Boltzmann study of the effect of metal foam on bubble behavior and heat transfer performance in flow boiling

Metal foams with high porosity, light weight, and large specific surface area can significantly enhance heat transfer performance. In this study, the lattice Boltzmann method coupled with the finite difference method is used to investigate the flow boiling characteristics of metal foam surface. Focus is given on the effects of Reynolds number, gravitational acceleration, wall superheat, and metal foam thickness on heat transfer performance. Studies show that increasing the Reynolds number enhances convective heat transfer on the metal foam surface but inhibits bubble nucleation. Compared with a smooth surface, the metal foam takes full advantage of the fluid shear force induced by the high-velocity fluid in the channel-center region, thereby reducing the dependence on buoyancy for bubble detachment. As the wall superheat and metal foam thickness increase, the wake effect induced by bubble detachment is enhanced. Subsequently, bubble detachment is facilitated and the liquid supply is enhanced. These results provide theoretical and applied technical guidance for the structural design of novel metal foam surfaces.

Experimental and numerical investigations on impact response of reinforced concrete beams with a sandwich panel protective layer

This paper investigates the response of reinforced concrete beams protected by an aluminium foam sandwich panel under impact loadings. A series of impact tests were conducted on one reinforced concrete beam and five beams with a protective layer, focusing on their dynamic responses and failure patterns. Test parameters included the type of protective layers (unprotected, aluminium foam and sandwich panel) and impact energy. Test results showed that the aluminium foam and sandwich panel could effectively protect the reinforced concrete beam from severe damage under impact loadings and converted the failure pattern of beams from shear failure to flexure-shear failure. Compared with the unprotected beam, the beams with a protective layer exhibited a lower peak force and developed a smaller mid-span deformation. Besides, the protective effects of the aluminium foam and sandwich panel were found to be nearly the same. Moreover, the peak force, plateau force and deformation of the beams were increased with the increasing impact energy. A numerical model was developed to investigate the energy distribution of beams with a sandwich panel protective layer. Based on the validated model, the effects of longitudinal reinforcement ratio and shear-span ratio on the impact response of beams were further studied. It was found that the deformation of beams increased significantly with the increasing shear-span ratio, whereas an increase in the longitudinal reinforcement ratio led to a decreased deformation. This study provides an important reference for designing reinforced concrete beams with a sandwich panel protective layer to resist impact loads.

A numerical simulation of heat transfer performance on MHD nanofluids in porous metal for enhancing CPU cooling efficiency

The main goal of this study is to enhance CPU cooling efficiency using nanofluids, and the novelty of the study lies in the investigation of heat transfer and convective flow of MHD nanofluid through porous metal structures and foam heat sink/source to improve CPU cooling efficiency. The governing equations for the flow model are solved using the BVP4C with MATLAB package through shooting techniques. The effects of various parameters on velocity, temperature fields, HT and drag force are discussed through graphical simulations. The results indicate that as the Reynolds and Darcy numbers rise, fluid flow velocity undergoes unique alterations. Higher Reynolds and Darcy numbers result in cooler temperatures, while higher heat generation lead to warmer temperatures.Boosting Prandtl number improves HT by 52% with Cu nanoparticles, whereas elevating heat generation values reduce HT by 6.43% more efficiently with Cu nanoparticles than Al2O3 nanoparticles. Raising the Hartmann number would boost drag force, but the Darcy number opposes it. An increase in Hartmann number leads to a decrease in HT by 30.16% for Al2O3-H2O nanofluids and 47.81% for Cu-H2O nanofluids. The findings contribute to the development of advanced computing devices, paving the way for more efficient and reliable electronic systems in various applications.

Correction: Effect of Compaction Pressure on Microstructural, Mechanical, and Thermal Properties of Aluminum Foams Processed through Space-Holder Technique

Correction: Effect of Compaction Pressure on Microstructural, Mechanical, and Thermal Properties of Aluminum Foams Processed through Space-Holder Technique

Friction Investigation of Closed-Cell Aluminium Foam during Radial-Constrained Test.

The energy-absorbing capacity and friction phenomena of different closed-cell aluminium foam-filled Al tube types are investigated through experimental compression tests. Concerning the kind of investigation, free, radial-constrained and friction tests occurred. The radial-constrained compression test results confirm that the process requires significantly more compression energy than without the constrain. Pushing away different pre-compressed foams inside the aluminium tube, the static and kinematic frictional resistances can be determined and the energy required to move them can be calculated. Knowing the value of the energy required for the frictional resistance, we can obtain how much of the energy surplus in radially inhibited compression is caused by the friction phenomena. The main goal present study is to reveal the magnitude of friction between the foam and the wall of the tube during the radially constrained test. The investigation used 0.4 and 0.7 g/cm3 density closed-cell aluminium foam whilst a compressive test was applied where the force-displacement data were recorded to calculate the absorbed energy due to friction. Considering the results of the test, it can be stated that 18% of the invested energy was used to overcome friction in the case of lighter foam and almost 23% with 0.7 g/cm3 foam during the radial-constrained test.

Study on the Wear Behaviour of Aluminium foam Reinforced Glass Fibre Epoxy Composites

Hand layup was used to fabricate the glass fibre reinforced aluminium foam epoxy composites in this study. On the manufactured materials, dry sliding wear experiments were performed. The effect of wearprocess parameters such asapplying load (kg), speed (m/s), and sliding distance (m) on specific wear rate (Ws) was investigatedand the obtained results were compared with neat glass fibre reinforced epoxy composite in this work. The outcome of these results showed that specific wear rate (Ws) of glassfibre epoxy composite containing aluminium foam decreased as compared with neat glass fibre reinforced polymer composites. Experimental results showed that a minimum wear rate of 10.1 �m was attained for the sliding velocity (1.5 m/s), Applied load (2 kg), and sliding distance (1000 m) in the fabricated composite laminates. It was observed thatthe resistance to wear in glass fibre reinforced aluminium foam composite was mainly due to the bond strength between aluminium foam and epoxy.

Fabrication and Evaluation of Mechanical and Tribological Properties of Al-Foam Produced by Powder Metallurgy Route

In the present study, the production of aluminum foam was carried out using the powder metallurgy technique, specifically employing the sintering – dissolution process (SDP). The SDP method, which constitutes a sequential series of four well-defined steps, was employed to achieve the desired foam structure and properties. These steps involved carefully controlling the parameters and conditions throughout the process to ensure successful foam formation. Aluminum powder with a particle size of (1.99 μm) as a raw material was mixed with NaCl with a particle size between (150-425μm) used as a space holder at different ratio (25, 35, 45and 55 wt. %.). Obtained Al-foam with 45% NaCl demonstrated the most optimal structure. Some additives (Mg) added to the powder mixture, it was found that the mechanical and the tribological properties of the produced foam were improved. The introduction of metal’s micro-particles led to a notable enhancement in both compressive stress and micro-hardness, the compressive stress increased substantially from 15.2 MPa to 56.5 MPa for the foam containing 45% NaCl and 45% NaCl + Add., respectively. While the micro-hardness exhibited a noteworthy increase from 51.5 HV to 62.1 HV. Results also showed important reduction in the wear rate from (0.00000155 g/cm) to (0.00000079 g/cm) for the Al-samples of (45% NaCl) and (45% NaCl+ Additive) respectively, the lowest value recorded for the coefficient of friction was (0.15) for (Al-Foam with 45% NaCl + Additive) compare to (0.19) and (0.21) for (Al-foam with 45% NaCl) and (pure Al) respectively at 10 N applied load and 800 rpm.

Modification of open-cell cast aluminum-silicon foams with strontium

The mechanical properties of open-cell aluminum foams can be influenced by enhancing the microstructure of the struts. The foams produced by investment casting face slow cooling rates, which makes it challenging to improve the morphology of the phases. In the case of aluminum silicon cast foams, the silicon phase accumulates on the surface of the struts, which leads to brittle fractures. In the present study, we successfully modified the silicon phase in open-cell AlSi7Mg and AlSi10Mg cast foams by adding strontium and investigated the influence of the strontium content on the microstructure and mechanical properties at the foam and strut levels. Despite the cooling rates of less than 0.5 °C/s during solidification, the strontium addition of 200–800 ppm effectively decreased the size of the silicon particles and improved their distribution in the micrometer-sized struts. Improvements in the compressive properties of the foams and the tensile properties of the struts only occurred at the strontium levels of 200 and 400 ppm. The effective modification in this casting condition is due to the limited solidification space, which favors the formation of the atomic clusters responsible for the modification.

Performance investigation of metal foam coupled to phase change material as coolant of photovoltaic concentrator systems: Optimization and electrical efficiency analysis

This research investigates the integration of graphitic metal foam with paraffin RT35HC to manage and reduce the temperature of PV cells, focusing on the rigorous examination of the synergistic effects of metal foam porosity and panel inclination on thermal management. A 2D numerical model was developed using ANSYS Fluent 14.0, where User-Defined Functions (UDFs) were employed to incorporate the Darcy-Brinkman-Forchheimer and Carman-Kozeny equations, accurately accounting for the effects of metal foam porosity on thermal conductivity and fluid flow resistance. Various foam porosities (ε = 0.80, 0.85, 0.90, 0.95, 1) were explored on both vertical and tilted panels across a spectrum of inclination angles (β= 0°, 30°, 45°, 75°, 90°). Results highlight critical parameters including PCM melting fraction, cell temperature evolution, and the resultant impact on solar cell electrical efficiency, both with and without metal foam. The integration of graphitic foam with RT35HC contributed to superior heat transfer and a marked reduction in cell temperature of the employed PV system by improving thermal conductivity and heat dissipation, particularly at slight inclination angles (β =0° to 30°), revealing a noteworthy enhancement in electrical efficiency ranging from 1.3 % to 3 %, respectively. Conversely, the absence of graphitic foam at steeper angles (β =45° to 90°) surprisingly strengthens the solar panel’s electrical performance. These findings provide valuable insights into the effects of metal foam integration at varying inclination angles, offering a pathway for the development of more efficient and reliable solar energy systems.