PSI - Issue 80

Marilyne Philibert et al. / Procedia Structural Integrity 80 (2026) 65–76 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Fig. 3. Resistance according to measured trace width for 100 mm traces compared for two flexible conductive silver inks.

Multiple strain gauges were printed using ACI FS0142 silver ink on flexible Kapton films, with a 10 mm by 10 mm designed measuring grid, a spacing between parallel traces of 0.2 mm, as shown in Fig. 4 (a), and effective trace length of 284 mm. The optimised printing parameters (Fig. 1, with 3 Ω for 100 mm trace length) were used and therefore, the expected resistance for the 284 mm trace length design is about 9 Ω.

Fig. 4. Printed strain gauges: (a) design and photo of the printing process, (b) photos of each strain gauge with blue cross indicating broken traces, (c) resistance according to measured trace width for each print with ellipse indicating mean value as centre and standard deviation as axis. The strain gauges were printed at two different print day: Print 1 and Print 2. A cross highlights broken traces in Fig. 4 (b). The nozzle was slightly blocked during Print 2 and cleaned half-way, hence the separated Print 2a and Print 2b in Fig. 4 (b) and the resulting thinner traces with higher resistance in Fig. 4 (c), which were prone to defect with 1/3 broken traces. Further results are presented in Table 3. Apart from Print 2a, resistance and trace width were found very consistent within a print, and consistent enough between different print days.

Table 3. Resistances and measured trace widths for printed strain gauges. Print 1 Print 2a

Print 2b

All prints

10.00 Ω 0.83 Ω

15.81 Ω 1.82 Ω

8.38 Ω 0.35 Ω

10.65 Ω 2.81 Ω

Resistance

Mean

Standard deviation

0.204 mm 0.012 mm

0.180 mm 0.003 mm

0.195 mm 0.007 mm

0.197 mm 0.013 mm

Trace width

Mean

Standard deviation