Numerical Macroscale Modeling of a Magnetized Ferromagnetic Fiber in Viscous Fluidic Environments

Herein, the experimental results of discontinuous ferromagnetic-fiber manipulation using magnetic-field interaction are presented. High-aspect-ratio steel fibers are realigned in viscous polydimethylsiloxanes (PDMSs) with electromagnets. The influence of the matrix viscosity, magnetic-field strength, and fiber-aspect ratio on the dynamics of the realignment process is investigated. To predict the fiber behavior under static magnetic fields, two commonly used theoretical models (hereinafter referred to as the torque model and the exponential model) are compared to a nonlinear regression model proposed by the authors. The latter model focuses on the alignment rate of a fiber as a function of the physical process parameters. To indicate the best fitting model for the experimental results, the statistical root-mean-square error (RMSE) values of the fitted models are assessed. A total of 54 comparisons are made between the exponential model and the authors' nonlinear regression model. In 50 cases, the nonlinear regression model provides a better fit.