Structural Damping of Fiber-Reinforced Composite Coupons

Description

This data set provides vibration-based coupon measurements for structural damping for a range of fiber-reinforced composites conducted by researchers from the National Laboratory of the Rockies (NLR). See references below for more detailed descriptions of the data.

Manufacturing Data: 'coupon-measurements.xlsx' provides manufacturing information and coupon measurements.

Dynamic Data Summary: 'full_dynamic_data.csv' provides loss factors for each coupon test and other associated details. See 'Data Categories' below for details about column headers.

Raw Dynamic Data: To reproduce the processed measurements for each coupon, download 'process_ldv.py' and follow instructions at the top of the script.

Raw Static Data: To reproduce the static data, download 'process_static.py' and follow instructions at the top of the script.

Experimental setup: See references below for more details about the experiments. Additionally, drawings of the tip masses used for these tests are provided in 'clamp-drawings.pdf'.

Data Categories

This section defines the columns in 'full_dynamic_data.csv'.

'panel' : Panel number designation

'angle' : angle in degrees that the coupon is cut at relative to the panel angle 0 definition. Angle 0 is generally aligned with the fiber roll.

'resin' : resin used for infusion of the panel. No resin is used if blank.

'fiber' : fiber material used for panel.

'date' : test date for the given sample.

'test_location' : identifier for tests conducted as part of 'CU', 'NLR1', or 'NLR2' campaigns.

'bolt_torque' : bolt torque setting used for bolts clamping coupons into end masses.

'coupon' : identifies a unique coupon when used with 'panel' and 'angle'. For aluminum coupons, this is the nominal length of the coupon.

'mode' : tested mode, '1' is the first bending, '2' is the second bending, 'T1' is the first torsion.

'index' : test index for the given coupon and day.

'filename' : relative file path in the .tar.gz file to the time series data for the given coupon test.

'infused_date' : date that the panel for the relevant coupons was infused.

'freq_hz' : identified natural frequency of tested mode from given coupon test.

'zeta_frac_crit_lsq' : fraction of critical damping for given test as identified from least squares fitting of the logscale decay.

'eta_loss_factor_lsq' : loss factor for the given test as calculated from least squares decay. Twice the value of 'zeta_frac_crit_lsq'.

'lsq_rsq' : R^2 value for the least squares fit used to identify the damping factor.

'area_error' : area based error metric used for data quality assessment as defined in [1].

'zeta_frac_crit_log_dec' : Fraction of critical damping as identified through log decrement method. Use of 'zeta_frac_crit_lsq' is preferred, but values should be similar.

References:

Most of these tests are described in detail in [1]. Ref. [2] provides description of a similar test setup and how the measured loss factors can be applied to predict structural damping for a real composite structure. Ongoing work is collecting additional measurements for the database and will provide additional descriptions.

[1] J. H. Porter, M. Chetan, D. Barnes, G. Vijayakumar, R. E. Murray, P. Bortolotti, P. Koutsogiannakis, N. H. Patino, M. Ruzzene, "Novel Comparison of Structural Damping in Composites Across Resin Systems and Scales", under review.

[2] "Novel application of the modal strain energy technique for state-of-the-art damping predictions", doi.org/10.1016/j.compstruct.2026.120394

Acknowledgements

This dataset was made possible thanks to a collaboration between NLR and Imperial College London, UK. Researcher Tom Mace and Professor Christoph W. Schwingshackl are gratefully acknowledged. Initial tests were conducted at the University of Colorado (CU) Boulder by NLR researchers. From CU, we would like to acknowledge Panagiotis Koutsogiannakis and Nicholas H. Patino for assisting with setup for the vibration measurements and Professor Massimo Ruzzene for sharing time using the laser Doppler vibrometer. The authors would also like to thank Paul Murdy (NLR) and Ariel Lusty (NLR) for helping with load frame testing for the provided static properties.

This work was authored by the National Laboratory of the Rockies for the U.S. Department of Energy (DOE), operated under Contract No. DE-AC36-08GO28308. This work was supported by the Laboratory Directed Research and Development (LDRD) Program at the National Laboratory of the Rockies. Additional funding provided by the U.S. Department of Energy Office of Critical Minerals and Energy Innovation Integrated Energy Systems Office. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes.