Abstract
Due to their high energy dissipation properties, in recent years, composite materials based on natural resins and fibers have been increasingly used. The paper studies the vibration behavior of composite bars reinforced with chopped wheat straw and, respectively, chopped sunflower seed shells. As matrix, an epoxy resin and, respectively, a hybrid resin based on rosin were used. A mathematical model useful for the study of damped vibrations is presented. For each of the analyzed bars, the frequency and damping factor for the first natural vibration mode are experimentally determined. Based on the experimental data, a coefficient that characterizes the vibration damping capacity for each bar is determined.
Keywords: sandwich composites; agricultural waste; 3-point bending behavior; vibration behavior