Psychoacoustic Implications of Nonlinear Dynamics in Carbon-Fiber-Reinforced Guitar Strings

The paper presents an examination of the nonlinear vibration and acoustic characteristics of carbon-wrapped composite guitar strings to address their sensitivity to material type, geometry, and boundary conditions. The existing metal and polymeric strings have often been constrained by problems of unstable vibration, restricted warmth, and environmental sensitivities. Composite string configurations provide better flexibility through microstructural design to vary stiffness, mass properties, and damping characteristics selectively. The work has developed a nonlinear simulation platform that accounts for geometric nonlinearities through von Karman geometric nonlinear kinematics, fractional-order viscoelastic damping to simulate frequent-dependent dissipation of energy, and a rate-dependent nonlinear shear-lag interface to simulate slip and contact friction at core-wrapped phase interfaces. It has used high-resolution spatial representations of vibration and interface phenomenon through a spectral element method, enabling finer numeric resolution of high-frequency modes and interfacial properties at significantly reduced problem sizes and simulations times. The work has provided robust validation of its nonlinear simulation predictions against existing experimentations and demonstrated an error margin of less than 0.5% in predicted frequencies. Besides validation and comparisons, this work has also included a dedicated sensitivity analysis to explore and quantify nonlinearities of various significant parameters, such as thickness of carbon-wrapped phase, orientation angles of carbon-wrapped phase, initial string tension, and fractional damping order, and their effects on fundamental frequencies, inharmonicity factors, and damping ratios of vibration modes and overall acoustic performance of carbon-wrapped composite materials.