Wednesday  |  Conference Center B  |  11:10 AM–11:30 AM

#13357, Impact Stress and Strain Analysis of PDMS Substrate Using High-speed Simultaneous Measurement System

In the ultimate consumer electronics market, flexible hybrid electronics (FHE) possesses substantial applicability. The application of FHE involves wearable devices, smart patches, smart textiles, in-vehicle systems, etc. Under an impact, different levels of stresses and strains may be sustained by different electronic components in the FHE, the reliability of the FHE is therefore difficult to be controlled. Consequently, the unpredictable damages may easily occur in the FHE products. Polydimethylsiloxane (PDMS) is a kind of polymer materials with high transparency and softness. PDMS substrate can be used for the protection layer of FHE to cushion impact forces. Therefore, analyzing the mechanical behavior of the PDMS substrate under impact loads may be helpful for the manufacturers to estimate and improve the reliability of FHE.

The full-field, non-destructive, automated, and real-time measurement of the mechanical behavior of materials and elements can be performed by using the photomechanics methods. By combining the digital photoelasticity and digital image correlation (DIC) method, a real-time full-field stress and strain measurement system was proposed in SEM 2021 Annual by Sung et al. [1]. Recently, by improving this measurement system, the authors have developed a real-time simultaneously full-field non-destructive stress and strain measurement system with high-speed camera [2] so that the dynamic stress and strain distribution can be obtained simultaneously.

In this study, this high-speed simultaneous measurement system [2] was employed to measure the full-field stress and strain distribution of the 230μm thick PDMS substrate under the ball drop impact process. The results showed that the stress and strain at impact point reached the maximum values of 2.3MPa and 12.4*103με, respectively. In contrast with the results shown in [1], it can be seen that the stress measurement value at impact moment obtained by the high-speed measurement system is much larger than that obtained by the low-speed measurement system (i.e. 0.27MPa). However, the strain measurement value at impact moment obtained by the high-speed measurement system is similar to that obtained by the low-speed measurement system (i.e. 15*103με). In addition, the measurement results will be compared with the simulation results by finite element analysis.

[1] P. C. Sung et al., 2021 SEM Annual, Paper No. 11411.
[2] P. C. Sung et al., (in Chinese) CTAM 2021, Paper No. 0179.

Po-Chi Sung   National Tsing Hua University
Wei-Chung Wang   National Tsing Hua University
Kuan-Chu Wu   Industrial Technology Research Institute
Frank Yang   Industrial Technology Research Institute