Determination of critical testing frequency of the short fiber‐reinforced plastics for efficient fatigue test

• Published in: Polymer composites Vol. 43; no. 2; pp. 768 - 781
• Main Authors: Jang, Jinhyeok, Pang, Hyonwoo, Choi, Jae‐Hyuk, Cho, Jeong‐Min, Yu, Woong‐Ryeol
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.02.2022; Blackwell Publishing Ltd
• Subjects: composites; Energy dissipation; failure; fatigue analysis; Fatigue life; Fatigue tests; Infrared analysis; Infrared cameras; Reinforced plastics; Short fibers; Thermodynamic properties; thermoplastics; viscoelastic properties
• ISSN: 0272-8397; 1548-0569
• DOI: 10.1002/pc.26408

Heat generated by viscous energy dissipation and friction during high‐frequency fatigue testing can reduce the fatigue life of short fiber‐reinforced plastics. Herein, we proposed new method of determining an appropriate testing frequency, taking into consideration the temperature increase in SFRPs during fatigue testing. An experimental procedure was developed to obtain viscoelastic and thermal parameters in a theoretical model using dynamic mechanical analyses and fatigue tests with an infrared camera. Then, according to the stress levels under tension in fatigue tests, a critical frequency was calculated to allow a temperature increase within 10°C. Finally, experimental fatigue tests at low stress levels and high frequencies were performed, demonstrating the applicability of the current method to design fatigue tests that take into account stress levels at a given frequency and a limited temperature rise.