The vibration of turbine blades during the operation of jet engines is a serious and complex issue that has garnered significant attention. In practical jet engines, dry friction damping is commonly used to suppress blade vibrations due to its reliability and efficiency. The equivalent damping ratio of dry friction dampers is a crucial metric for evaluating their performance. However, calculating dry friction dampers’ damping ratio for actual structures involves nonlinear vibration calculations, which are challenging and often lack precision. A method combining simulation and experimentation to calculate the equivalent damping ratio of a structure is proposed. In a laboratory setting, the vibration response of turbine blades under centrifugal load and the damping effect of under-platform dampers were analyzed using oil excitation. The research results indicate that this method can effectively calculate the equivalent damping ratio of actual structures. The findings provide robust support for the design of under-platform dampers and the vibration analysis of turbine blades.