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The fatigue behaviour of continuous wire polymer composite (CWPC) fabricated by fused filament fabrication was investigated. Four compositions were examined: polylactic acid (PLA), PLA with copper wire (Cu), thermoplastic polyurethane (TPU), and TPU with Cu wire. Residual properties were measured after different sets of number of cycles (10 , 10 , 10 ). Residual strengths were 89.736% and 70.464% of the ultimate tensile strength of the original material after 10 cycles for PLA CWPC and TPU CWPC, respectively. A one-way analysis of variance (ANOVA) statistical tests showed insignificant changes in the residual strengths of PLA-based materials after an increasing number of cycles and significant changes for the TPU-based materials. CWPC electromechanical properties under fatigue test demonstrated reverse piezoresistivity behavior. A strain-controlled fatigue life analytical model was compared to the experimental results showing good agreement. This study demonstrates the applicability of FFF technique to print sensors with continuous integrated wire with tunable properties.

This work studies the fatigue behavior of biodegradable composites of thermoplastic starch (TPS) reinforced with different amounts of date palm fibers (DPF) (20, 50, and 70 wt%). Composite with 50 wt% fiber content had higher static and fatigue strengths compared to other composites. The alternating stress at which the composites lasted for 10 7 cycles was about 16% of the flexural strength. Mathematical models following the assumptions of D’Amore et al. (1996) and Mao and Mahadevan (2002) were shown to give a good agreement with experimental results of the residual strengths under various fatigue cycles and of the fatigue damage index at different levels of stresses.