Flexible fibers are simulated in discrete element method (DEM) simulations to measure the collisional dissipation rate. The incorporation of particle flexibility brings forth the description of translational, rotational, and vibrational degrees of freedom, and potential energy as individual granular temperatures that are summed together into a total granular temperature. The effects of varying coefficient of restitution (e), coefficient of friction (mu), bond damping coefficient (beta(b)), bond Young's modulus (E-b), and solid volume fraction (alpha(s)) are analyzed for flexible fibers of aspect ratio 4. The dissipation rate is significantly affected by the bond damping coefficient, where those effects are superimposable along with e and mu. The granular kinetic theory scaling for alpha(s) is found to be applicable up to solid fractions 0.4. The combination of these two findings along with the trends related to E-b highlight strategies for developing collisional dissipation rate models for flexible fibers. (C) 2019 Elsevier B.V. All rights reserved.