No abstract

The fly ash (FA) particulates are used in this study to reinforce the polyurethane foam (PUF) core. The FA particles inclusion improves the mechanical performance of the PUF core under compression by increasing its modulus of elasticity. Low-velocity impacts have damage dynamics that are pretty similar to quasi-static indentation. Consequently, the indentation resistance capability of the PUF core is investigated for three types of indenter nose tips with varied FA wt. Percentages (flat-circular, hemispherical, and conical). The results reveal that the reinforced foam core’s resistance varies with reinforcement percentage under indentation. However, FA reinforcement to PUF does not necessarily improve indentation resistance. The damage mechanism of the PUF core under indentation has been evaluated for each type of indenter. The interaction of crushing, shear, and tear of the damaged surface with the change in indenter nose tip has been explained with 0–20% variation of FA particles. Scanning electron microscope (SEM) images are taken for the analysis of the damaged PUF core cross-section at the indented location. Earlier mechanical findings of the scatter in deformation behavior with the indenter nose tip geometry are substantiated by the SEM studies.

No abstract

Magno-elastic coupling characteristics in giant magnetostrictive thin films depend on a myriad of factors, comprising variability in Young’s modulus, thermally induced pre-stresses, the direction of the applied magnetic field and the substrate to film thickness ratio, demagnetization field etc. Due to the aforementioned reasons, the giant magnetostrictive thin films usually display characteristics that may contrast with the bulk giant magnetostrictive materials. This work studies magnetostrictive film on a compliant substrate using a generalized 3-D magneto-thermo-elastic nonlinear constitutive model with the elasticity theory to include such stimuli sensitive coupled magneto-thermo-elastic response. The numerical simulation of the magnetostrictive film on the compliant substrate in the form of a cantilever shows good agreement with the existing experimental data. The substrate and film thickness ratio effect on the thermal strain, Young’s modulus, magnetization and magnetostriction of films was meticulously analyzed. It has been revealed that the magneto-elastic responses rely strongly on the substrate-to-film thickness ratio. Thus, it is possible to obtain the tunable properties by controlling the composite film's thickness ratio in the design state of smart devices.

No abstract