*Article* **Modeling and Testing of Flexible Structures with Selected Planar Patterns Used in Biomedical Applications**

**Pavel Marsalek 1,\*, Martin Sotola 1, David Rybansky 1, Vojtech Repa 1, Radim Halama 1, Martin Fusek <sup>1</sup> and Jiri Prokop 2,3**


**Abstract:** Flexible structures (FS) are thin shells with a pattern of holes. The stiffness of the structure in the normal direction is reduced by the shape of gaps rather than by the choice of the material based on mechanical properties such as Young's modulus. This paper presents virtual prototyping of 3D printed flexible structures with selected planar patterns using laboratory testing and computer modeling. The objective of this work is to develop a non-linear computational model evaluating the structure's stiffness and its experimental verification; in addition, we aimed to identify the best of the proposed patterns with respect to its stiffness: load-bearing capacity ratio. Following validation, the validated computational model is used for a parametric study of selected patterns. Nylon—Polyamide 12—was chosen for the purposes of this study as an appropriate flexible material suitable for 3D printing. At the end of the work, a computational model of the selected structure with modeling of load-bearing capacity is presented. The obtained results can be used in the design of external biomedical applications such as orthoses, prostheses, cranial remoulding helmets padding, or a new type of adaptive cushions. This paper is an extension of the conference paper: "Modeling and Testing of 3D Printed Flexible Structures with Three-pointed Star Pattern Used in Biomedical Applications" by authors Repa et al.

**Keywords:** wearable; flexible; structure; stiffness; biomedical; mechanics; simulation; pattern; 3D print; PA12
