TY - JOUR
T1 - Acoustic Modal Testing of Bicycle Rims
AU - Ford, Matthew
AU - Peng, Patrick
AU - Balogun, Oluwaseyi
N1 - Funding Information:
Acknowledgements This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1324585. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. This research was also supported by a Grant-In-Aid of Research from Sigma Xi. We would like to thank Dr. Joel Fenner 1 Equation (13) is strictly valid for symmetric radially-spoked wheels, but gives a good approximation for other cases. See Ref. [8].
Funding Information:
This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1324585. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. This research was also supported by a Grant-In-Aid of Research from Sigma Xi. We would like to thank Dr. Joel Fenner for his help performing the diametral compression tests, and Professor Jonathan Siegel and the Department of Communication Sciences and Disorders at Northwestern for the use of their anechoic chamber. We are also grateful to Professor Jim Papadopoulos for many enlightening discussions on bicycle wheel mechanics.
PY - 2018/3/1
Y1 - 2018/3/1
N2 - The stiffness, strength, and safety of a bicycle wheel depend critically on the stiffness of its rim. However, the complicated cross-sections of modern bicycle rims make estimation of the stiffness by geometric methods very difficult. We have measured the radial bending stiffness and lateral-torsional stiffness of bicycle rims by experimental modal analysis using a smartphone microphone. Our acoustic method is fast, cheap, and non-destructive, and estimates the radial bending stiffness, EI11, to within 8% and the torsional stiffness, GJ, to within 11% as compared with a direct mechanical test. The acoustic method also provides a direct measurement of the coupled lateral-torsional effective stiffness, which is necessary for calculating many useful properties of bicycle wheels such as stiffness, buckling tension, and the influence of spoke tensioning. For a complete bicycle wheel, the lateral stiffness can be determined by a superposition of equivalent springs for each mode in series, where each mode stiffness contains a rim stiffness and spoke stiffness combined in parallel. We give example calculations on two realistic bicycle wheels using our experimentally derived rim properties to show how stiff spokes can compensate for a flexible rim, while a very stiff rim doesn’t necessarily result in a stiff wheel.
AB - The stiffness, strength, and safety of a bicycle wheel depend critically on the stiffness of its rim. However, the complicated cross-sections of modern bicycle rims make estimation of the stiffness by geometric methods very difficult. We have measured the radial bending stiffness and lateral-torsional stiffness of bicycle rims by experimental modal analysis using a smartphone microphone. Our acoustic method is fast, cheap, and non-destructive, and estimates the radial bending stiffness, EI11, to within 8% and the torsional stiffness, GJ, to within 11% as compared with a direct mechanical test. The acoustic method also provides a direct measurement of the coupled lateral-torsional effective stiffness, which is necessary for calculating many useful properties of bicycle wheels such as stiffness, buckling tension, and the influence of spoke tensioning. For a complete bicycle wheel, the lateral stiffness can be determined by a superposition of equivalent springs for each mode in series, where each mode stiffness contains a rim stiffness and spoke stiffness combined in parallel. We give example calculations on two realistic bicycle wheels using our experimentally derived rim properties to show how stiff spokes can compensate for a flexible rim, while a very stiff rim doesn’t necessarily result in a stiff wheel.
KW - Acoustics
KW - Bicycle wheel
KW - Experimental modal analysis
KW - Smartphone applications
KW - Structural characterization
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U2 - 10.1007/s10921-018-0471-7
DO - 10.1007/s10921-018-0471-7
M3 - Article
AN - SCOPUS:85042080941
VL - 37
JO - Journal of Nondestructive Evaluation
JF - Journal of Nondestructive Evaluation
SN - 0195-9298
IS - 1
M1 - 16
ER -