The article deals with the investigation of the influence of changes in the internal structure of composite materials on their dynamic properties. The research is focused on 3D printed samples with different arrangements of reinforcing fibers. The samples are printed on a Markforged Mark Two 3D printer using chopped carbon fiber filled nylon (Onyx) as the base material and long carbon fibers as reinforcement. An impact test method is used in which the sample is subjected to a short pulse of force and the frequency response of the structure is monitored by an accelerometer. The obtained results serve to determine the natural frequencies and internal damping of individual structures. The results will be compared with the numerical analysis in the ANSYS Workbench program. The virtual model is created in the Ansys Composite Preprocessing (ACP) module and the results are obtained from modal and harmonic analysis. The knowledge and results of this work can be used in the development of new components in the transport industry, where an important factor is the low weight and sufficient strength of the components, which can transmit vibrations from various sources of oscillation, such as engines and road irregularities.