Mahdi Rahmani - Department of Mechanical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
Armen Adamian - Department of Mechanical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
Ahmad Hosseini-Sianaki - Department of Mechanical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran

In this research, the effect of CaCO۳ nanoparticles was experimentally investigated on vibrational damping behavior and static mechanical properties of polypropylene (PP). Hammer tests along with modal analysis were carried out to evaluate the forced vibration behavior of composite plates under  one edge clamped support conditions while tensile tests were performed to assess the static mechanical properties. A comparison of the results showed an increment in the static mechanical properties of nanocomposites by increasing the nanoparticles content in the PP matrix. Composite with ۱۰ wt.% nanoparticles showed the highest rise in Young’s modulus (۳۹.۷۱ %) compared to pure PP. An increment in Young’s modulus and stiffness led to an increasing trend in the damped natural frequencies of the nanocomposites so that the composite with ۱۰ wt. % nanoparticles showed the highest damped natural frequency augmentation (۲۳.۶ %, ۳۶.۷۸ %, and ۲۵۲.۶۲ %) compared to pure PP in the first three modes. In addition, an enhancement in the nanoparticles content of the PP matrix led to an increasing trend in damping ratios of the nanocomposites such that the composite with ۱۰ wt. % nanoparticles in the first mode (۲۸.۹۹ %) and composite with ۷.۵ wt. % nanoparticles in the second and third modes (۴۱۸.۶۶ % and ۹.۹۳ %) showed the highest rise in damping ratio compared to pure PP. Increasing damping ratios can be due to the proper dispersion of nanoparticles in the matrix and consequently energy dissipation of the stick-slip mechanism between the matrix and nanoparticles. Moreover, high nanoparticle contents had destructive effects on both the static and dynamic behavior of the composites.

calcium carbonate nanoparticles, Forced vibration, Modal Analysis, nanocomposite