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Response of polycarbonate, poly(methylmethacrylate), and epoxy resins to dynamic contact loading I. Experimental results
Author(s) -
Hillig William B.
Publication year - 1985
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760250606
Subject(s) - materials science , epoxy , viscoelasticity , polycarbonate , composite material , penetration (warfare) , spheres , laplace transform , penetration depth , optics , mathematical analysis , mathematics , physics , operations research , astronomy
Abstract Measurements of the resistance force to a wide range of contact loadings have been performed on poly(methylmethacrylate), polycarbonate, and epoxy specimens. Rigid spherical indenters of 4.5, 9, and 18 mm diameter, as well as cones of various apex angles, were driven into thick specimens at constant velocity over the range 0.005 to 150000 mm/min. The objective of this study was to develop a data base useful for the understanding and analysis of the phenomena involved when polymeric solids are impacted by small hard bodies. Spheres and cones were used because these symmetrical shapes offer the best chance for analysis in terms of viscoelastic extensions of the classical Hertz elastic contact problem. Measurements covered penetration depths from first detection of contact, where the strains are smallest and the material response should most likely be interpretable in terms of linear viscoelastic analysis, to much greater depths where the strains far exceed the yield values. The observations are tabulated, as are the values of parameters that allow the data to be modeled to within experimental error. These parameters fit into a specially developed empirical law designed to facilitate subsequent treatment of the data using Laplace transform methods. An analysis is offered to try to sort out time‐dependent force relaxation from depth‐dependent force increase during the progress of the penetration. The results of the response at small penetration depths are in broad accord with published relaxation moduli. However, the dependence of force upon indenter geometry does not follow simple expectation.