Experimental Investigation on the Low Velocity Impact Response of Fibre Foam Metal Laminates

The combination of fibre metal laminates (FML) and sandwich structures can significantly increase the performance under impact of FMLs. The goal of this work was to create a material that will combine the superior properties of FMLs and foam sandwich structures in terms of the impact resistance and simultaneously have lower density and fewer disadvantages related to the manufacturing. An extensive impact testing campaign has been done using conventional fibre metal laminates (carbon- and glass-based) and in the proposed fibre foam metal laminates to assess and compare their behaviour. The main difference was observed in the energy absorption mechanisms. The dominant failure mechanism for fibre foam laminates is the formation of delaminations and matrix cracks while in the conventional fibre metal laminate the main failure mode is fibre cracking due to high local stress concentrations. The reduction in the fibre cracking leads to a better after-impact resistance of this type of structure improving the safety of the structures manufactured with these materials.

Effects of Particle Combinations With Different Wettability on Foam Structure and Stability

Particle addition is an important method to prepare foam metal, and it is of great significance to clarify the mechanism of particle stabilizing liquid metal foam. In this paper, ethanol-water solution system is used to simulate liquid melt foam. By changing the wettability of particles to adjust the distribution position of particles in foam, two types of particles with different wettability are added, which are mixed and optimized in a certain proportion to improve the foam stability as much as possible. The main mechanism is that the large wetting angle particles at the gas-liquid interface to slow down the gas migration, while small wetting angle particles exist in the liquid film, which can reduce the liquid drainage velocity. The experimental results show that the effect of particle wettability on foam structure is greater than that on viscosity enhancement. The particles with large wetting angle are beneficial to the formation and stability of foam, and the particles with small wetting angle cannot stabilize the foam alone. The effect of two types of particle combinations with different wettability on foam stability is better than that of single type of particle. Considering the height and uniformity of the foam structure, the optimal particle combination is finally obtained.

Foam-Metal Casing Treatment on an Axial Flow Compressor: Stability Improvement and Noise Reduction

This paper concerns the stability improvement and noise reduction of an axial compressor caused by the foam metal casing treatment (FMCT). Three FMCTs with different PPI (pores per inch), 20, 35, and 50, are tested experimentally. Two installation locations of foam metal in casing are considered and investigated. At location 1, it is found that the FMCT improves the stall margin by 5.4%~8.7% and the attenuation of compressor noise is up to 5 dB. At location 2, the stall margin is extended by 22.2%~37.1% but increasing the noise mostly. Besides, foam metal at location 1 causes less efficiency loss than that in location 2. Based on the analysis in near-casing pressure distribution, spanwise performance comparison and stall inception, the mechanism of the FMCT for enhancing compressor stability is also discussed.

Determining the Thermal Effects of Channels on Porous Heat Sinks Under Forced Convection Conditions with Nanofluid: An Experimental and Numerical Study

The present study determines the effects which foam metals and Nanofluid have on the performance of a simulated CPU. The present study employs yAl2O3-water Nanofluid and 6061- T6 Aluminum foam metal with a porosity of 0.91 and permeability of 40 pores per linear inch formed in bulk media and porously filled channels. The concentrations evaluated are 0.1%, 0.3%, and 0.6% by volume. The study shall consider both original empirical results and numerical results obtained from COMSOL Multiphysics, showing good agreement with a maximum error of 4.3%. The present study. When considering the average Nusselt number as the representation of the strength of the heat transfer mechanism, and as such ignoring pumping requirements, it is shown that the use of porously filled channels interacting with 0.6% Nanofluid produces the most effective combination. However, when pumping power is relevant, a combination of bulk porous media interacting with 0.3% Nanofluid is observed. The results obtained herein can be applied to the cooling of electronics, or any other system wherein a general inward heat flux is applied.

Determining the Thermal Effects of Channels on Porous Heat Sinks Under Forced Convection Conditions with Nanofluid: An Experimental and Numerical Study

The present study determines the effects which foam metals and Nanofluid have on the performance of a simulated CPU. The present study employs yAl2O3-water Nanofluid and 6061- T6 Aluminum foam metal with a porosity of 0.91 and permeability of 40 pores per linear inch formed in bulk media and porously filled channels. The concentrations evaluated are 0.1%, 0.3%, and 0.6% by volume. The study shall consider both original empirical results and numerical results obtained from COMSOL Multiphysics, showing good agreement with a maximum error of 4.3%. The present study. When considering the average Nusselt number as the representation of the strength of the heat transfer mechanism, and as such ignoring pumping requirements, it is shown that the use of porously filled channels interacting with 0.6% Nanofluid produces the most effective combination. However, when pumping power is relevant, a combination of bulk porous media interacting with 0.3% Nanofluid is observed. The results obtained herein can be applied to the cooling of electronics, or any other system wherein a general inward heat flux is applied.