title: Non-Hertzian behavior in binary collisions of plastic balls derived from impact acoustics.
abstract: This paper presents slight deviations from Hertz's impact law, inferred from acoustic signatures of polypropylene ball collisions. An impact acoustics model is used to fit the acoustic data. The model is built upon a generalized relationship between impact force (F) and deformation (xi) of the form F=kappaxi(alpha). Agreement with experiment is reached when alpha and kappa differ from Hertz's values by -6.25% and +1%, respectively. The difference is ascribable to non-idealities such as slight material inhomogeneities, impact-point asymmetry, plasticity etc. Also, the collision energy released as sound, which is usually dismissed as negligible, is derived from data fitting. The acoustic-to-incident energy ratio, dependent on impact duration, is constrained to be on the order of 100 ppm.
authors.affiliation: Department of Physics, University of Louisiana at Lafayette, PO Box 44210, Lafayette, Louisiana 70504, USA.
authors.forename: Joshua
authors.initials: J
authors.lastname: Riner
authors.forename: Andi
authors.initials: A
authors.lastname: Petculescu
mesh_terms: D000054:Acceleration; D000162:Acoustics; D055119:Elastic Modulus; D004735:Energy Transfer; D008962:Models, Theoretical; D011126:Polypropylenes / Q000737:chemistry*; D011312:Pressure; D013016:Sound; D013018:Sound Spectrography; D013997:Time Factors; D014732:Vibration
chemical_list: D011126:Polypropylenes