In this paper, the fatigue strength of a structural similar sample made of polymer composite material (PCM) is evaluated. Fatigue tests of structurally similar samples from PCM were carried out using an electrodynamic vibration stand. Based on the test results, a fatigue curve is constructed. A design model of a structurally similar sample has been developed, taking into account the design features and fixing the sample in the tooling during testing. In the future, it is planned to use the obtained computational model to study a structurally similar sample with a bundle obtained during testing and transfer the results to a full-size model.