Development and experimental verification of optimum design methods for dynamic absorbers for inhibiting pattern formation phenomena in contact rotating systems

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Previous studies have considered that the major occurrence mechanism of pattern formation phenomena is unstable vibrations generated in linear time delay systems. Many characteristics of these phenomena have been successfully explained using this mechanism.In this study, the following investigations were performed to establish practical and easy-to-use methods for preventing the occurrence of pattern formation phenomena.1. Development of a new stability analysis method and clarification of fundamental concepts(1) A new stability analysis method based on the existence condition for boundaries between stable and unstable regions was developed for two-and three-degree-of-freedom systems.(2) A structural design method that inhibits the occurrence of pattern formation phenomena was formulated by using this new stability analysis method.2. Establishment of optimum design for dynamic absorbers for inhibiting the pattern formation phenomena.(1) For single-degree-of-freedom systems, an optimum … More design method that does not require completely characterizing the system was formulated by assuming the worst conditions that maximize the instability intensity of the main system.(2) For multi-degree-of-freedom systems, a method involving individually designing dynamic absorbers for each mode was proposed. This method effectively stabilized all the modes and greatly reduced the design time.3. Experimental verificationAn experimental system was produced to verify the effectiveness of the proposed stability analysis method. This was a multistage roll system that models the viscoelastic roll used in paper-making machines, etc. Experiments with single-degree-of-freedom systems were mainly carried out. The results indicate that unstable vibrations occur in the same range as that of the results obtained using the new stability analysis method, verifying the effectiveness of this method. Based on the results obtained in this study, verification of the effectiveness of the prevention method using dynamic absorbers will be performed in the future. Less