Quasi-static and high strain rate response of Kevlar reinforced thermoplastics

• Published in: Polymer testing 2021-01, Vol.93, p.106964, Article 106964
• Main Authors: Chouhan, Hemant, Bhalla, Neelanchali Asija, Bandaru, Aswani Kumar, Gebremeskel, Shishay Amare, Bhatnagar, Naresh
• Format: Article
• Language: English
• Subjects: Failure mechanisms; High strain rate; Kevlar; Quasi-static; Thermoplastic matrices
• ISSN: 0142-9418
• DOI: 10.1016/j.polymertesting.2020.106964

The present study deals with the quasi-static and high strain rate characterization of Kevlar-129 based thermoplastic composites. Two different thermoplastic matrices, namely, Polypropylene (PP) and Polyetherimide (PEI) were used to manufacture composite laminates. Quasi-static compression tests were performed at strain rates of 0.041 s−1 and 0.045 s−1. High strain rate tests were performed using a split Hopkinson pressure bar apparatus within the strain rates ranging from 2548 s−1 to 4379 s−1. Stress-strain relations reveals the rate-sensitive behaviour of composites. Kevlar/PP (K-PP) showed higher peak stress under quasi-static loading as compared to the high strain rate test. Comparable peak stresses were revealed under quasi-static and high strain rate loading for Kevlar/PEI (K-PEI) composite. Also, high strain rate compression properties such as peak stress, peak strain and toughness of K-PP were 25%, 27% and 6% higher than that of the K-PEI composite. The failure mechanisms of both the composites were characterized through macroscopic and scanning electron microscopy. K-PP failed majorly due to matrix crush and fibre failure while K-PEI failed due to shear cracking. Damage study reveals that a single fibre based composite system can be tailored to act as an energy-absorbing or dissipating material system by varying the thermoplastic matrix materials. •Static and dynamic compressive properties of Kevlar reinforced high-performance polymers.•Kevlar/Polypropylene outperforms over Kevlar/Polyetherimide under both the quasi-static and high strain rate loads.•The quasi-static strength of Kevlar/Polypropylene is 25% higher than its high strain rate strength.•Polypropylene matrix results in ductile failure, while the Polyetherimide matrix results in brittle failure.