During deep drilling for fossil deposits or geothermal energy, unwanted vibrations occur during drilling due to the slim design of the drill string. Especially self-excited high-frequency torsional oscillation can reduce drilling progress and component life. In order to identify possibilities to reduce these critical vibrations, a method is developed using underground measurement data to determine the energy flow and thus the nonlinear torque characteristic at the bit. This allows to quantify the excitation in order to identify stable and unstable operational parameters and to optimize the drilling progress. Using the characterized excitation mechanism, a semi-analytical method is developed to predict the long-term dynamic response of the self-excited drill string by identifying the dominant self-excited mode. The findings are used to investigate damping mechanisms for their applicability in drilling systems. Taking into account specific borehole effects such as a large number of critical modes and changing boundary conditions, as well as other constraints such as limited installation space and power supply, damping mechanisms of different complexity are investigated in more detail. Special attention is given to the achievable damping and the associated stability of the drill string modes. The generated simulative results and analytical solutions of the different dampers are validated using a test rig specifically designed to test the effectiveness of different dampers under underground conditions. Subsequently, different optimization strategies for positioning the dampers in the drill string are discussed. Finally, the damper prototype developed with the company Baker Hughes is presented, which proves the practical suitability of the research work carried out.weiterlesen