Static And Dynamic Mechanical Properties And Strain Rate Sensitivity Of Thermoplastic Based Polymers And Composites Using Split Hopkinson Pressure Bar Apparatus
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Date
2013-04
Authors
Omar, Mohd Firdaus
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
In this study, an experimental technique, based on the compression Split
Hopkinson Pressure Bar (SHPB), was introduced to perform dynamic compression
testing whereas a conventional universal testing machine was used to perform static
compression testing. These two techniques were used to experimentally investigate
the interactive effect of strain rates towards the compressive properties of various
thermoplastic-based materials. All of the thermoplastic-based materials used in this
study were fabricated using a hot press process. The SHPB results were initially
verified and calibrated. The results indicated that all tested thermoplastic specimens
(i.e. PP, PE, and PC) showed a great dependency on the strain rate applied; where the
yield stress, compression modulus, and compressive strength, were all proportionally
increased as the strain rate was increased. Interestingly, both Eyring and basic power
law equations were almost agreed with the experimental results over a wide range of
strain rates investigated. The effect of molecular structure, on the static and dynamic
mechanical properties of thermoplastic polymer, was also determined using
polyethylene specimens with different molecular structures (i.e. LDPE, LLDPE, and
HDPE). The results indicated that the molecular structure of polyethylene did affect
its mechanical properties in terms of yield behaviour, stiffness, strength, rate
sensitivity, activation volume, and absorbed energy. For thermoplastic based
reinforced composites, two types of particulate fillers were added into the
polypropylene matrix namely zinc oxide and mica.
Description
Keywords
Thermoplastic Based Polymers And Composites , Split Hopkinson Pressure Bar Apparatus