Finite Element Analysis and Experimental Validation of Carbon Fiber-Reinforced Nitrile Rubber Composite Mount Baffles for Vibration Isolation Applications

Abstract

On-board machinery in marine vessels such as ships and submarines generates vibrations that can degrade equipment longevity, interfere with communication systems, and compromise stealth capabilities. Among various mitigation techniques, passive anti-vibration mount baffles are widely employed for their effectiveness in isolating vibrations above specified frequencies. This study presents a comprehensive finite element (FE) analysis and experimental validation of nitrile rubber (NBR)-based composite mount baffles reinforced with varying percentages of carbon fiber (5–25%). The composite design was modelled using CAD tools and analysed using advanced finite element methods to assess static deformation and dynamic performance. Material properties were experimentally characterized and used for accurate FE modelling. The mount baffle with 5% carbon fiber exhibited the highest deflection (1.24 mm) and the lowest resonance frequency (16 Hz), indicating superior low-frequency isolation characteristics. A comparative study highlights the correlation between fiber loading, stiffness, and vibration isolation performance.

Introduction

Onboard machinery vibrations in ships and submarines can cause equipment damage, communication interference, and compromise stealth. Anti-vibration mount baffles effectively reduce these issues. This study focuses on designing composite mount baffles with a 1200 kg load rating, considering factors like load, dimensional constraints, static deflection, isolation frequency, damping, and operating environment.

The mount baffles consist of stainless steel structural parts and a nitrile rubber composite elastomeric stack reinforced with varying percentages (5% to 25%) of short carbon fibers. Samples were prepared and tested for mechanical and damping properties including hardness, tensile strength, elongation, tear strength, and compression set. These material properties informed finite element analysis (FEA) models.

Hyperelastic and viscoelastic behaviors of the composites were modeled using the Mooney-Rivlin two-parameter model based on uniaxial tensile data. Static structural and harmonic analyses were performed in COMSOL Multiphysics to assess deflection, resonance frequency, transmissibility, and energy dissipation under load.

Results showed that increasing fiber content increased stiffness, hardness, tensile and tear strength, but reduced elongation and compression set. Higher fiber loadings decreased static deflection and raised resonance frequency. The 5% fiber mount baffle offered the best low-frequency vibration isolation with higher deflection and lower resonance frequency, suitable for low-frequency applications. Conversely, the 25% fiber baffle was stiffer with higher resonance frequency, less effective for low-frequency vibration isolation.

The FEA results closely matched experimental data, validating the modeling approach.

Conclusion

A carbon fiber-reinforced NBR composite mount baffle was developed and validated for vibration isolation in marine applications. The mount baffle with 5% carbon fiber demonstrated optimal performance, combining adequate stiffness with the lowest resonance frequency. FE simulation results aligned well with experimental data, validating the modelling approach. Higher fiber contents were found to compromise low-frequency isolation, making Mount Baffle 1 the most suitable candidate for such applications.

References

B.C. Chakraborty: Polymers for vibration damping applications, Elsevier publications,2020. [2] K. Shajahan, Arun Sundar RS, Ramesh Kumar AV and Reji John, Investigations on short carbon fibre filled NBR composites for fabrication of lowfrequency vibration isolator, Defence Science Journal (Under print Jun 2025) [3] R.E. Blake: Harris’ shock and vibration handbook, The McGraw-Hill Companies, Edition 2, 2010. [4] D. D. L. Chung: Review Materials for vibration damping, Journal of Materials Science, Kluwer Academic Publishers, 36, 5733 – 5737, 2001 [5] Trisha Sain, Julien Meaud, Greg Hulbert, Ellen M. Arruda, Anthony M. Waas “Simultaneously high stiffness and damping in a class of wavy layered composites,” Composite Structures .,101, pp.104–110,2013. [6] D.O. Thompson, D.E. Chimenti “Wave Propagation in a Composite with Wavy Reinforcing Fibers”, Review of Progress in Quantitative Nondestructive Evaluation., Vol. 14,1995. [7] M. R. Piggott “The effect of fibre waviness on the mechanical properties of unidirectional fibre composites: a review,” Composites Science and Technology 53, pp- 201-205,1995. [8] G.Marchmann, E.Veron , “Comparison of hyperelastic model for rubber like materials’, Rubber Chemistry and Technology, 79,835-858, 2014. [9] Patel Sanket Bharat, Shivprakash B Barve, Sandeep G Thorat and Samata S Majumdar – “Design and Analysis of anti-vibration mount baffle for G+3 Elevator” International Journal of Current Engineering and Technology (IJCET) ISSN2277-4106 – April 2014. [10] Shajahan K, Arun Sundar RS, Ramesh Kumar AV and Reji John, Design and Validation of a Low Frequency Anti-Vibration Mount using NBR-Short Carbon Fibre Composite, Advances in Military Technology (Under print April 2025)

Copyright

Copyright © 2025 Shajahan K, Arun Sundar RS, Ramesh Kumar AV, Reji John. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.