Experimental and numerical modal analysis of short carbon fiber reinforced polyethersulfone composites

Abstract

Damping is the resistance to the vibratory motion. Viscous dampers are generally used to resist the repetitive motion and dissipate the energy out of the vibrating system. However, material of the vibrating body itself will have ability to dissipate the vibratory energy which is often referred as material damping. Even though, material damping is very small compared to viscous damping, in many practical situations, this may also play significant role. This work was focused on the evaluation of material damping of short carbon fiber (SCF) reinforced polyethersulfone (PES) composites by adopting free vibration test methodology. In addition, Young’s modulus of the PES/SCF composites was determined through their natural frequencies. Investigation was made by reinforcing the PES with 10, 20 and 30 wt.% of SCF using twin screw extruder and injection moulding machine. Free vibration response of the clamped-free composite beam was captured through an accelerometer sensor. Free vibration test revealed that PES composites showed reduction in damping with increase in SCF content due to stiffening of the polymer. Natural frequencies of PES composites increased with increase in SCF loading. Tensile modulus enhanced by 267% with respect to neat polymer for 30 wt. % of SCF reinforcement. Also, numerical frequency analysis was carried out using Abaqus finite element package and simulated results closely fitted with the experimental data.