Serbest-Serbest Sınır Koşullarında Askı İpi Malzemesinin Modal Parametreler Üzerindeki Etkisinin Deneysel Araştırması
Abstract
Mühendislik yapılarının tasarım aşamasında, dinamik davranışlarının doğru bir şekilde belirlenmesi, uzun ömürlü ve güvenli bir kullanım için hayati öneme sahiptir. Bu amaçla yaygın olarak kullanılan yöntemlerden biri olan Deneysel Modal Analiz (DMA), yapıların doğal frekansları, sönüm oranları ve frekans yanıtı gibi temel modal parametrelerini sağlayarak dinamik davranışlarını ortaya koyar. DMA uygulamalarında yapılara, genellikle tek veya çoklu noktalardan kuvvet uygulanır ve yanıtlar çeşitli sınır koşulları altında sensörler aracılığıyla ölçülür. Bu sınır koşullarından biri olan serbest-serbest (free-free) koşulu, yapıların iplerle askıya alınarak kısıtlanmamış bir davranış sergilemesini simüle eder. Bu çalışmanın amacı, askı ipi malzemesinin bir yapının dinamik davranışları üzerindeki etkisini incelemektedir. Deneylerde iki farklı ip malzemeden - naylon ve kauçuk - oluşan dört farklı kombinasyon kullanılmıştır. Sonuçlar, farklı askı malzemeleri kullanıldığında doğal frekansların büyük ölçüde değişmediğini, ancak sönüm oranlarının belirgin şekilde etkilendiğini göstermektedir. Ayrıca, harmonik yanıt ölçümleri, askı malzemesinden kaynaklanan sönüm oranı farklarının açıkça tespit edilebildiğini doğrulamaktadır.
Project Number
2021.06.05.1221
References
- Bahari, A. R., Yunus, M. A., Abdul Rani, M. N., Nalisa, A., & Shah, M. A. S. A. (2019). Investigation on the effects of suspension stiffness using experimental modal analysis and finite element model updating. IOP Conference Series: Materials Science and Engineering, 506(1). https://doi.org/10.1088/1757-899X/506/1/012043
- Carne, T. G., Griffith, D. T., & Casias, M. E. (2007, February 19–22). Support conditions for free boundary-condition modal testing. In Proceedings of the IMAC-XXV A Conference & Exposition on Structural Dynamics (ISBN 9781604237597). Orlando, FL, USA. https://www.osti.gov/servlets/purl/1266149
- Chang, C. S., & Hodges, D. H. (2007). Parametric studies on ground vibration test modeling for highly flexible aircraft. Journal of Aircraft, 44(6), 2049–2059. https://doi.org/10.2514/1.30733
- Cooley, V., & Giunta, A. (1992, April 13). Laboratory evaluation of two advanced suspension devices for ground vibration testing of large space structures. Paper presented at the 33rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, Dallas, TX, United States. https://doi.org/10.2514/6.1992-2334
- Cui, M., Liu, H., Jiang, H., Zheng, Y., Wang, X., & Liu, W. (2022). Active vibration optimal control of piezoelectric cantilever beam with uncertainties. Measurement and Control, 55(5–6), 359–369. https://doi.org/10.1177/00202940221091244
- Ewins, D. J. (2000). Modal testing: Theory, practice and application (2nd ed.). Research Studies Press Ltd. Geweth, C. A., Baydoun, S. K., Saati, F., Sepahvand, K., & Marburg, S. (2021). Effect of boundary conditions in the experimental determination of structural damping. Mechanical Systems and Signal Processing, 146, Article 107052. https://doi.org/10.1016/j.ymssp.2020.107052
- Huang, W., Ji, H., Qiu, J., & Cheng, L. (2016). Wave Energy Focalization in a Plate With Imperfect Two-Dimensional Acoustic Black Hole Indentation. Journal of Vibration and Acoustics, 138(6). https://doi.org/10.1115/1.4034080
- Jiang, D., Huang, Z., Wang, G., Wang, Y., Zhu, R., & Hang, X. (2024). Reducing effects of boundary condition in modal testing of flexible structures. Journal of Mechanical Science and Technology, 38(1), 89–99. https://doi.org/10.1007/s12206-023-1208-9
- Munsi, A. S. M. Y., Waddell, A. J., & Walker, C. A. (2002). Modal analysis of a lightweight structure - Investigation of the effects of the supports on the structural dynamics. Mechanical Systems and Signal Processing, 16(2–3), 273–284. https://doi.org/10.1006/mssp.2000.1393
- Sahu, G. N., & Kanchwala, H. (2024). Experimental modal analysis of a tire: An exploration of different operating and boundary conditions. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 46(11). https://doi.org/10.1007/s40430-024-05237-7
- Shen, L., & He, S. (2024). Modal analysis and frequency matching study of subway bogie frame under ambient excitation. Scientific Reports, 14(1). https://doi.org/10.1038/s41598-024-72146-z
Experimental Investigation of Suspension Cord Material Influence on Modal Parameters in Free-Free Boundary Conditions
Abstract
During the design stage of engineering structures, determining their dynamic response is essential to ensure performance and long service life. Experimental Modal Analysis (EMA) is a widely used method for this purpose, as it provides critical modal parameters (natural frequencies, damping ratios, frequency response) and reveals the dynamic behavior of structures. In the EMA, structures are typically excited at single or multiple locations, and the responses are measured using sensors under various boundary conditions. One common approach is the free-free boundary condition, which involves suspending test structures using suspension cords to simulate unconstrained behavior. This study investigates how the material of suspension cords affects the dynamic characteristics of a structure. Two cord materials—nylon and rubber—along with four different combinations of these cords were tested. Results indicate that while the natural frequencies remain unchanged (%1-%2 difference) across different suspension materials, the damping ratio is notably affected. The measured damping ratios ranged from 0.95% (nylon) to 3.45% (rubber), demonstrating the significant influence of suspension material on energy dissipation. Additionally, harmonic response measurements confirm that differences in damping ratios due to the suspension material are clearly detectable.
Ethical Statement
This study does not involve human or animal participants. All procedures followed scientific and ethical principles, and all referenced studies are appropriately cited.
Supporting Institution
Authors gratefully thank the Scientific Research Project (BAP) Coordination Unit of Düzce University for financial support (Project number: 2021.06.05.1221).
Project Number
2021.06.05.1221
Thanks
Authors gratefully thank the Scientific Research Project (BAP) Coordination Unit of Düzce University for financial support (Project number: 2021.06.05.1221).
References
- Bahari, A. R., Yunus, M. A., Abdul Rani, M. N., Nalisa, A., & Shah, M. A. S. A. (2019). Investigation on the effects of suspension stiffness using experimental modal analysis and finite element model updating. IOP Conference Series: Materials Science and Engineering, 506(1). https://doi.org/10.1088/1757-899X/506/1/012043
- Carne, T. G., Griffith, D. T., & Casias, M. E. (2007, February 19–22). Support conditions for free boundary-condition modal testing. In Proceedings of the IMAC-XXV A Conference & Exposition on Structural Dynamics (ISBN 9781604237597). Orlando, FL, USA. https://www.osti.gov/servlets/purl/1266149
- Chang, C. S., & Hodges, D. H. (2007). Parametric studies on ground vibration test modeling for highly flexible aircraft. Journal of Aircraft, 44(6), 2049–2059. https://doi.org/10.2514/1.30733
- Cooley, V., & Giunta, A. (1992, April 13). Laboratory evaluation of two advanced suspension devices for ground vibration testing of large space structures. Paper presented at the 33rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, Dallas, TX, United States. https://doi.org/10.2514/6.1992-2334
- Cui, M., Liu, H., Jiang, H., Zheng, Y., Wang, X., & Liu, W. (2022). Active vibration optimal control of piezoelectric cantilever beam with uncertainties. Measurement and Control, 55(5–6), 359–369. https://doi.org/10.1177/00202940221091244
- Ewins, D. J. (2000). Modal testing: Theory, practice and application (2nd ed.). Research Studies Press Ltd. Geweth, C. A., Baydoun, S. K., Saati, F., Sepahvand, K., & Marburg, S. (2021). Effect of boundary conditions in the experimental determination of structural damping. Mechanical Systems and Signal Processing, 146, Article 107052. https://doi.org/10.1016/j.ymssp.2020.107052
- Huang, W., Ji, H., Qiu, J., & Cheng, L. (2016). Wave Energy Focalization in a Plate With Imperfect Two-Dimensional Acoustic Black Hole Indentation. Journal of Vibration and Acoustics, 138(6). https://doi.org/10.1115/1.4034080
- Jiang, D., Huang, Z., Wang, G., Wang, Y., Zhu, R., & Hang, X. (2024). Reducing effects of boundary condition in modal testing of flexible structures. Journal of Mechanical Science and Technology, 38(1), 89–99. https://doi.org/10.1007/s12206-023-1208-9
- Munsi, A. S. M. Y., Waddell, A. J., & Walker, C. A. (2002). Modal analysis of a lightweight structure - Investigation of the effects of the supports on the structural dynamics. Mechanical Systems and Signal Processing, 16(2–3), 273–284. https://doi.org/10.1006/mssp.2000.1393
- Sahu, G. N., & Kanchwala, H. (2024). Experimental modal analysis of a tire: An exploration of different operating and boundary conditions. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 46(11). https://doi.org/10.1007/s40430-024-05237-7
- Shen, L., & He, S. (2024). Modal analysis and frequency matching study of subway bogie frame under ambient excitation. Scientific Reports, 14(1). https://doi.org/10.1038/s41598-024-72146-z
Details
| Primary Language | English |
|---|---|
| Subjects | Machine Theory and Dynamics, Mechanical Engineering (Other) |
| Journal Section | Articles |
| Authors | |
| Project Number | 2021.06.05.1221 |
| Publication Date | October 30, 2025 |
| Submission Date | May 30, 2025 |
| Acceptance Date | August 4, 2025 |
| Published in Issue | Year 2025 Volume: 13 Issue: 4 |
