Effect of Geometrical Modeling on the Prediction of Laser-Induced Heat Transfer in Metal Foam

Abstract

Over the past several decades, aluminum foam (Al-foam) has found increasing popularity in industrial applications due to its unique material properties. Unfortunately, till date Al-foam can only be affordably manufactured in flat panels, and it becomes necessary to bend the foam to the final shape that is required in engineering applications. Past studies have shown that thin cell walls crack and collapse when conventional mechanical bending methods are used. Laser forming, on the other hand, was shown to be able to bend the material without causing fractures and cell collapse. This study was focused on the thermal aspects of laser forming of closed-cell Al-foam. An infrared camera was used to measure the transient temperature response of Al-foam to stationary and moving laser sources. Moreover, three different numerical models were developed to determine how much geometrical accuracy is needed to obtain a good agreement with experimental data. Different levels of geometrical complexity were used, including a simple solid geometry, a Kelvin-cell based geometry, and a highly accurate porous geometry that was based on an X-ray computed tomography (CT) scan. The numerical results were validated with the experimental data, and the performances of the numerical models were compared.

Laser Forming of Sandwich Panels With Metal Foam Cores

“…The assumptions of this model and the sources for the material data are discussed in detail in Refs. [17] and [18]. The x and y mesh refinement was the same as in Ref.…”

“…In the Kelvin model, the same element size was used for the cohesive layer as in the adjacent metal foam elements. The thermal and mechanical boundary conditions were the same as in prior analyses [17,18], and an absorption coefficient of A ¼ 0.6 was used [32].…”

“…2(b), in which the cavities of the foam core are explicitly modeled using Kelvin-cell geometries. On one hand, the foam model geometry appears to be less important in sandwich panels than in free-standing foams [17], because the laser absorption in the top facesheet is the same regardless of the foam geometry. Also, the temperature distributions during laser scans are very similar in both models, as shown in Fig.…”

“…A viable alternative to the aforementioned processes is laser forming, since it is based on thermally induced mechanical deformation and requires no physical contact with the treated material. The process has successfully been used to bend a variety of different metal foams, such as closed-cell foams [17,18], open-cell foams [19], as well as foams with protective skins [20]. Yet, no attempt has been made to apply laser forming to sandwich panels with metal foam cores.…”

A Review on Prodution of Aluminium Metal Foams

“…Microstructural analysis, porosity and density were investigated. [8] Tizian Bucher, et. al (2016), This study was targeted to determine what quantity geometrical accuracy is required to get a good agreement with experimental information on the thermal aspects of laser forming of closedcell aluminium foam.…”