Experimental study of tensile properties of PMMA at intermediate strain rate

Tensile tests of polymethylmethacrylate (PMMA) at quasi-static loading conditions and at intermediate strain rates were performed on MTS810 materials test system and on a self-developed intermediate strain rate materials testing apparatus, respectively. The tested results show that the mechanical properties of PMMA are strongly rate sensitive: When the strain rate increases, the strength and initial modulus increase, while the fracture strain decreases. Scanning electronic microscope (SEM) fractography on the fracture surface indicates that a relationship between the morphology of fracture surface and strain rates exists: When the strain rate increases, the mirror area gets smaller, the ribs and the gaps between ribs get wider, and the number of the ribs gets smaller. At the strain rate of 18.6 s(-1) the rib area disappears, and only a large range of brittle shatter fracture morphology remains. This is coincident with the high-rate enbrittlement of PMMA. (C) 2004 Elsevier B.V All rights reserved.