Jekel, Dominic (2018):
Optimization of Damping in Self-Excited Mechanical Systems.
Darmstadt, Technische Universität,
[Ph.D. Thesis]
Abstract
Self-excited vibrations, such as squealing of disc brakes or galloping of overhead transmission lines, are often accompanied by undesired phenomena. The appearance of self-excitation is ascribed to an instability originating either from negative damping or from non-conservative coupling of motion coordinates. In a linearized description, the stability behavior of such circulatory systems strongly depends on the structure of the damping matrix as well as the relation of all matrices involved. Considering the distinct physical origins of energy dissipation, some of the resulting damping matrices have a stabilizing effect, while others may contribute to destabilization.
In this context, the present thesis addresses two major scientific objectives. First, a deeper understanding is promoted regarding the influence of velocity proportional forces on the stability of linear mechanical systems featuring circulatory and gyroscopic terms. Analytical investigations deliver detailed insights into the required structure of the damping matrix either for stabilization or the avoidance of destabilization. Second, stability is assessed by means of quantitative measures. On this basis, a technique for stability optimization is established. The method relies on decomposing the damping matrix into component matrices which are associated with different physical origins. Suitable variation of these submatrices yields a reduced tendency of self-excitation. Beneficial damping configurations are determined with respect to predefined constraints, as they naturally appear in engineering. The meaningfulness of the obtained results is judged in terms of dependence on parameter fluctuations and technical feasibility. Serving as representative examples, various models of disc brakes and overhead transmission lines are studied numerically at different levels of complexity.
| Item Type: | Ph.D. Thesis | ||||
|---|---|---|---|---|---|
| Erschienen: | 2018 | ||||
| Creators: | Jekel, Dominic | ||||
| Title: | Optimization of Damping in Self-Excited Mechanical Systems | ||||
| Language: | English | ||||
| Abstract: | Self-excited vibrations, such as squealing of disc brakes or galloping of overhead transmission lines, are often accompanied by undesired phenomena. The appearance of self-excitation is ascribed to an instability originating either from negative damping or from non-conservative coupling of motion coordinates. In a linearized description, the stability behavior of such circulatory systems strongly depends on the structure of the damping matrix as well as the relation of all matrices involved. Considering the distinct physical origins of energy dissipation, some of the resulting damping matrices have a stabilizing effect, while others may contribute to destabilization. In this context, the present thesis addresses two major scientific objectives. First, a deeper understanding is promoted regarding the influence of velocity proportional forces on the stability of linear mechanical systems featuring circulatory and gyroscopic terms. Analytical investigations deliver detailed insights into the required structure of the damping matrix either for stabilization or the avoidance of destabilization. Second, stability is assessed by means of quantitative measures. On this basis, a technique for stability optimization is established. The method relies on decomposing the damping matrix into component matrices which are associated with different physical origins. Suitable variation of these submatrices yields a reduced tendency of self-excitation. Beneficial damping configurations are determined with respect to predefined constraints, as they naturally appear in engineering. The meaningfulness of the obtained results is judged in terms of dependence on parameter fluctuations and technical feasibility. Serving as representative examples, various models of disc brakes and overhead transmission lines are studied numerically at different levels of complexity. |
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| Place of Publication: | Darmstadt | ||||
| Divisions: | 16 Department of Mechanical Engineering 16 Department of Mechanical Engineering > Dynamics and Vibrations Exzellenzinitiative Exzellenzinitiative > Graduate Schools Exzellenzinitiative > Graduate Schools > Graduate School of Computational Engineering (CE) |
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| Date Deposited: | 28 Oct 2018 20:55 | ||||
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/8112 | ||||
| URN: | urn:nbn:de:tuda-tuprints-81120 | ||||
| PPN: | |||||
| Referees: | Hagedorn, Prof. Peter ; Schweizer, Prof. Bernhard | ||||
| Refereed / Verteidigung / mdl. Prüfung: | 9 October 2018 | ||||
| Alternative Abstract: |
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