On the Influence of Cyclic Loading Frequency on Fatigue Limit of Short-Fiber Thermoplastics

Document Type

Article

Publication Date

6-1-2026

Abstract

This study investigates the influence of cyclic loading frequency on the fatigue limit of additively manufactured-compression molded (AM-CM) short carbon fiber thermoplastics (20 wt% CF-ABS). Accelerated fatigue characterization was performed using passive infrared thermography under a staircase loading protocol at 5, 10, 15, and 20 Hz. Displacement accumulation, stabilized surface temperature ((Formula presented.)), and fatigue fracture entropy (FFE) were jointly analyzed to capture frequency-dependent damage mechanisms. Results show a notable increase in fatigue limit from 52.14% (Formula presented.) at 5 Hz to 61.14% (Formula presented.) at 20 Hz. Higher frequencies suppressed viscoelastic deformation, reduced hysteretic energy dissipation, and shifted failure morphology from matrix-dominated cracking to fiber breakage. Constant amplitude tests at 60% (Formula presented.) confirmed these trends, with specimens failing at 5 Hz but surviving 3 million cycles at 20 Hz. Across all frequencies, FFE remained consistent (0.096 (Formula presented.) 0.0144 kJ/m (Formula presented.) K), supporting its role as a rate-independent scalar indicator of fatigue damage.

Publication Source (Journal or Book title)

Fatigue and Fracture of Engineering Materials and Structures

First Page

2455

Last Page

2464

This document is currently not available here.

Share

COinS