Title
Experimental and numerical investigation of vibration and damping properties of Alstonia macrophylla fiber reinforced polypropylene composites: effect of fiber concentration
Authors
HARSHAVARDHAN BETTEGOWDA, SHETTAHALLI MANTAIAH VINU KUMAR, ERUSAGOUNDER SAKTHIVELMURUGAN, RAVICHANDRAN ARUMUGAM THANGAVEL, CHANDRASEKARAN SASIKUMAR and SANTHOSH NAGULAN

Received October 17, 2025
Published Volume 60 Issue 5-6 May-June
Keywords natural frequency, damping, PP composites, effective stiffness, model analysis

Abstract
Many automotive and aerospace industries have shown increasing interest in the manufacture of components from natural fiber composites due to their unique properties, such as low density, low processing cost, biodegradability, recyclability, and tailorable mechanical properties, compared to the synthetic fiber composites. In this context, Alstonia macrophylla (ASM) fiber reinforced polypropylene (ASM/PP) composites were fabricated using the hot-pressing technique. The main focus of this study was to investigate the effect of fiber content on the vibration and damping properties of the ASM/PP composites. ASM fiber was reinforced into PP on volume fraction basis ranging from 0 to 50 vol% in increments of 10 vol%. The resulting composites were designated as Neat PP, A10, A20, A30, A40 and A50 composites, respectively. Free vibration test results revealed that the addition of 40 vol% of ASM fiber into PP enhanced the natural frequency (ModeI) of the composites. However, at lower fiber content, natural frequency of the ASM/PP composites was reduced due to the softening effect dominated by the PP matrix. Highest damping ratio was exhibited by A30 composites, however beyond 30 vol%, a significant drop in damping ratio was observed. This may be owing to poor agglomeration of the fibers at higher concentration. Experimental results were found to be in good agreement with numerical results obtained from Abaqus simulations, with an error limited to 2.28%. CAE models of the specimens were prepared as per their actual dimension. However, for enhancing effectiveness of the simulation results, the mass of the accelerometer was considered. FESEM analysis on the fractured surface supported the improvement in damping and stiffness properties.