Influence of loading frequency on the fatigue behaviour of coir fibre reinforced PP composite

Published Date
February 2015, Vol.41:184–190, doi:10.1016/j.polymertesting.2014.12.002

Test method

• Author 

• Dijan Vinicius Osti de Moraes ^a,
• Rodrigo Magnabosco ^a,,
• Gustavo Henrique Bolognesi Donato ^a,
• Sílvia Helena Prado Bettini ^b,
• Marcela Caroline Antunes ^b,

• aFEI University, Brazil
• bUFSCar, Brazil

Received 31 October 2014. Accepted 5 December 2014. Available online 13 December 2014.

Abstract

The influence of loading frequency on the fatigue behaviour of a coir fibre reinforced polypropylene (PP) composite was studied. The mechanical behaviour was assessed through monotonic tensile and flexural tests, followed by cyclic bending fatigue tests employing a new specimen geometry, with loading frequencies ranging from 5 to 35 Hz. Results revealed that higher strain rates during monotonic loading lead to higher flexural strength, and higher loading frequencies in cyclic tests promote reduction in fatigue life. Fractographic examination showed that one of the reasons for reduced fatigue life under higher loading frequencies might be related to increased heat generation by hysteresis, leading to a fatigue damage mechanism governed by temperature effects. The results, thus, encourage the development of good practices regarding test frequencies in order to be able to uncouple thermal and mechanical effects and provide relevant data for structural integrity assessments.

Keywords

Composites

Polypropylene

Coir fibre

Fatigue

Loading frequency

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• ∗ 
  Corresponding author. FEI University, Av. H. A. C. Branco, 3972 – office K5-09, São Bernardo do Campo, SP 09850-901, Brazil. Fax: +55 11 43532900x2051.
  
  

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