PSI - Issue 52

Dita Puspitasari et al. / Procedia Structural Integrity 52 (2024) 410–417 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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shows stable model for every loading cases. Validation of data tests and stable material models indicates that the data entered can be used to simulate hyperelastic materials according to the selected model.

Fig. 5 a) boundary condition of model b) given displacement for modelling compression (8 mm) c) 2D porous hydrogel before compression simulation d) after compression.

Then, the 2D hydrogel model is simulated using the previously validated model and the boundary conditions and loading described in section 2.5. Fig.5a shows the boundary condition. It is set to be no movement in all translational and rotational directions. This condition simulates the bottom support of the specimen. While Fig.5b shows displacement direction. It simulates strain given to the specimen when it accepts compression in the mechanical test. Then Fig. 5c-d shows the state of the hydrogel before and after loading. The strain given to the model produces stress on the simulation results. The color contour shown in the figure shows the stress value in the model with a multiplier of -1 to indicate if the stress is acting in the negative y direction, representing compressive stress. The value of the stress that appears due to the given strain is in units of Pa, so the maximum compressive stress that appears is 244 Kpa. This value is smaller than the results of the compression test, which gives rise to a maximum stress of up to 135 MPa in the sample. Such difference between experiment and simulation results may be attributed to the oversimplified 2D model from a hydrogel high porous sample. It was assumed that the 2D model accommodated stress reaction due to the strain given for the 3D sample. So, it does not work for the hyperelastic material model. 4. Conclusions In conclusion, the sericin/PVA/MOL scaffold was successfully fabricated by the freezing-thawing method which is proven by the formation of porous structure hydrogel. The porosity of the hydrogel from the SEM image result was not representative enough and therefore the micro-CT test was conducted to prove that the hydrogel has good porosity for scaffold application. The hyperelasticity test also proved that the hydrogel was hyperelastic and suitable for diabetic foot ulcer applications. Simplifying high porous hyperelastic material with 2D porous material is not sufficient. It can not accommodate non-linear behavior that happens over all axis of 3D model material. Acknowledgments The authors would like to thank The Asahi Glass Foundation 2022 for the financial support of this research.