The work aims at validating a methodology for 3D printing of gears with involute gearing and evaluating their mechanical properties using infrared camera. A general methodology for the setup of 3D printing of gears made of polymeric materials has been developed, which can be used in technical practice in order to replace parts produced by conventional methods. An experiment was prepared determination of the distribution of the 1st invariant of the stress tensor and phase shift using a modal exciter and an IR camera. The values of the 1st invariant of the stress invariant were found. For these measurements, the lock-in thermography method was used, using a modal exciter we force loaded a gear in which the response to the load was registered. The aim was to obtain the distribution of the strain or stress field on the loaded tooth. The experimental method used also belongs to the field of non-destructive testing (NDT), and with suitable experimental parameters we can also obtain information from the layers below the surface, as demonstrated in the phase images. The practical benefit is to provide a competitive advantage to companies that will exploit the properties of polymeric materials by knowing the mechanical properties of these materials.

Rotor dynamics plays a crucial role in the performance and safety of rotating machinery, with disk position and unbalance significantly impacting system behavior. This study investigates the dynamic characteristics of two rotor configurations: a centrally mounted unbalanced disk (Rotor05un) and an off-center unbalanced disk (Rotor025un). Using numerical simulations and Monte Carlo analysis, we examined critical speeds and orbital patterns for both configurations. Probability distributions of shaft orbital positions revealed distinct patterns for each configuration. Quantile analysis revealed approximate linear trends for Rotor025un, suggesting higher system stiffness and more predictable behavior near critical speeds. Cross-sectional analyses of the orbits provided insights into the complex interactions between disk position, gyroscopic effects, and system natural frequencies. These findings provide valuable insights for rotor system design, particularly for applications with non-ideal mass distributions. The study goes beyond traditional critical speed analysis to examine orbital patterns and point on orbit occurrence from a probabilistic perspective. Based on the simulation of the orbits, an orbital is determined that allows the probability of the shaft occurring at the analyzed distance from the origin to be determined. The paper also offers insights into the complex interaction behavior of chosen rotor configurations and highlights the importance of considering disk position in predicting and optimizing rotor dynamic behavior, contributing to the development of more robust and efficient rotating machinery.