سلوك التخميد للمواد المسامية المستخدمة في هياكل الصفائح الطبائقيه

Damping Behavior of a Porous Material Core Used in Sandwich Plate Structures

Abstract

Sandwich panels are commonly used in marine ships structures and
aerospace applications due to their light weight and design flexibility In, like
that is suitable for, automotive and civil engineering applications, as it offers
reduced weight while maintaining mechanical strength, this study examines the
effect of foam core density and thickness on the dynamic performance of
sandwich panels, particularly focusing on natural frequencies and vibration
behavior. Three foam densities (26, 34, and 40 kg/m³) were studied, alongside
two core thicknesses, (25 mm and 50 mm) were used to investigate their effects
on the vibration characteristics of foam structures.
The methodology combined Analytical calculations, experimental
measurements, and numerical simulations. Analytical models were used to
estimate the natural frequencies of sandwich panels based on material properties
and geometry. Experimental, panels were fabricated with the selected foam
cores and tested using three-point bending setups according to ASTM standards,
along with impact tests simulating real-life conditions. Numerical simulations
were carried out using ANSYS software to calculate the natural frequencies and
validate the experimental data.
The results manifested that increasing the foam density generally led to a
decrease in the fundamental natural frequency of the sandwich panels. This
trend was observed for both thicknesses, though the decrease was more
noticeable in thicker cores. The reduction in natural frequency with higher
density is attributed to the added mass of the denser foam, which affects the
panel’s vibrational characteristics. Conversely, lower density foams resulted in
higher natural frequencies in proportion 19%, which is advantageous in
applications where the vibration control is critical, and The experimental
damping coefficients were calculated at thicknesses of (25 and 50 mm) for three
different foam densities (26, 34, 40 kg/m³), with values ranging between
(0.08253 – 0.15396).