PSI - Issue 37

Shirsha Bose et al. / Procedia Structural Integrity 37 (2022) 131–138 Bose et al., 2021/ Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 3: Stress-distributions in square and circular micro-island for gold (a) and chromium (b) films (red colour indicates respective yield strengths of metallic films; plastic stresses are shown in grey). Distributions of stress component S11 for collagen substrate along edge (c) and central lines (d) for both micro-islands.

3.2. Damage analysis

The damage at the interface between the collagen and chromium layers for 5% applied strain are presented in Fig. 4 for both micro-islands. The interfacial damage of the cohesive zone is represented by a damage parameter CSDMG, with 0 indicating the intact surface while 1 corresponding to the complete failure. As expected, the maximum damage was observed along the edges of the loading direction (AD for square and along A for circular) for both micro-islands (Fig. 4a). It is interesting to note that for 5% applied strain, the evolution of damage did not affect the central line (BC) of the devices.

Fig. 4: Damage parameter CSDMG (a) and total normalised delaminated area (b) at various levels of applied strain for both micro-islands for chromium (Normalisation was performed with respect to the total surface area of the collagen-metal interface).

To analyse the performance of the micro-islands, normalized delaminated area with the increasing strain (at 1.25%,