Rapid estimation of the fatigue limit of Smart Polymer-Matrix Composites (PMC) using the self-heating tests

Given it is usually highly problematic and time-consuming to evaluate the real in-situ damage and fatigue limit of the polymer-matrix composite (PMC) materials, this study investigates the electrical capacitance variation of polyvinylidene difluoride (PVDF) piezopolymer transducer embedded within PMC specimens made with a polyester resin reinforced by 2/2 twill glass fabrics and submitted to the self-heating tests. During the successive cyclic loadings, the non-intrusiveness of the PVDF sensors was ensured as well as the conformity of the fatigue limit estimated using both stabilized temperature and capacitance measurements. Novel damage estimation curves were proposed based on different temperature and capacitance variables. Thereby, the originality of this study lies in the assessment of the fatigue limit and damage quantification of PMC materials using two physical magnitudes: electrical capacitance and temperature variations. These two quantities provide a fairly fast estimation of the fatigue limit with a slight percentage difference of 9%.