Polymeric smart foams are lightweight and multifunctional porous materials that are sensitive to the magnetic field due to the presence of magnetic particles embedded in the matrix. Recently, a constant magnetic field has been exploited to align the particles along the magnetic field lines during the formation of the porous structure. In this paper, a new field-structuring process was developed that makes use of a time-profiled magnetic field during the foaming process to control the geometrical features of the particles aggregates. The effects of magnetic field strength as well as the switch-on and switch-off times on the magnetoelastic behavior of the smart foams were investigated. It was proven that the alignment of the particles results in both a strong relative sensitivity to the magnetic field and a positive stress change, whose extent depends on the geometrical features of the developed aggregates.
Keywords: magnetic particles; magnetoelasticity; smart foams; variable magnetic field.