Comparison of Mode Shapes of Carbon-Fiber-Reinforced Plastic Material Considering Carbon Fiber Direction

Previous studies have demonstrated the sensitivity of the dynamic behavior of carbon-fiber-reinforced plastic (CFRP) material over the carbon fiber direction by performing uniaxial excitation tests on a simple specimen. However, the variations in modal parameters (damping coefficient and resonance frequency) over the direction of carbon fiber have been partially explained in previous studies because all modal parameters have only been calculated using the representative summed frequency response function without modal analysis. In this study, the dynamic behavior of CFRP specimens was identified from experimental modal analysis and compared five CFRP specimens (carbon fiber direction: 0 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees) and an isotropic SCS13A specimen using the modal assurance criterion. The first four modes were derived from the SCS13A specimen; they were used as reference modes after verifying with the analysis results from a finite element model. Most of the four mode shapes were found in all CFRP specimens, and the similarity increased when the carbon fiber direction was more than 45 degrees. The anisotropic nature was dominant in three cases of carbon fiber, from 0 degrees to 45 degrees, and the most sensitive case was found in Specimen #3.

Automated summary

The study compared the dynamic behavior of CFRP specimens with different carbon fiber directions using experimental modal analysis and the modal assurance criterion, finding increased similarity among specimens when the carbon fiber direction exceeded 45 degrees. Anisotropic nature was dominant in three cases from 0 degrees to 45 degrees, with the most sensitive case identified in Specimen #3.