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Experimental measurement of internal stresses in polypropylene‐injected disks
Author(s) -
Delbarre P.,
Jasse B.,
Pabiot J.,
Rietsch F.
Publication year - 1993
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1993.070490407
Subject(s) - polypropylene , materials science , composite material , deformation (meteorology) , mold , optical microscope , stress (linguistics) , internal stress , thermal , microscope , microscopy , optics , thermodynamics , scanning electron microscope , physics , philosophy , linguistics
Disks in polypropylene were injected in a mold with an unbalanced cooling pattern to induce warpage. The internal stresses were determined using IR dichroism for molecular orientation measurement and an original method for thermal stress assessment, on the basis of the analysis of the dilatometrical behavior of microtomed cuts removed from the part. From both experimental results and structural observations with an optical microscope, a simple model is proposed to describe the warpage due to the effect of unbalanced cooling. A constant deformation was observed and cannot be described by our model, but calculated relative deformations of the part geometry are in good agreement with experimental results. © 1993 John Wiley & Sons, Inc.