Analyse of strain and stress on different stretchable conductive ink materials by numerical method

Abstract

This study determines the optimal stretchability performance of different materials on a conductive pattern by using maximum principal elastic strain and Von Mises stress analysis. It was performed by using finite element analysis (FEA) modelling approaches. The FEA modelling was initiated from previous studies of comparative difference in strain and stress caused by stretching the screen printed straight-line pattern (baseline) and curving wave pattern using graphene conductive ink as material. The research is using a sine wave pattern because it has the best results from the previous studies compared to other patterns. Five different FEA modelling conductive materials were developed, which are copper as the baseline, graphene, carbon nanotube (CNT), carbon black, and silver. The maximum principal elastic strain and equal stress (Von Mises stress) obtained by FEA modelling can be used to approximate which material has better elasticity. After 20% elongation, the maximum principal elastic strain of carbon-based conductive ink carbon black and graphene, 14.521 x 10-3 and 14.578 x 10-3, respectively, produced the best results, with percentage difference values of 2.63% and 2.24% from copper (baseline). As compared to the copper (1761.7MPa) conductive ink, the Von Mises stress value for carbon black (241.76 MPa) and graphene (257.34 MPa) is about 7 and 6 times lower stress respectively. There are no significant differences in strain and stress values between graphene and carbon black conductive inks. The findings show that carbon black can be an alternative to graphene as a good conductive ink. Furthermore, this research demonstrates that the FEA method can be used to investigate the stretchability of conductive ink.