Diatoms in new design

The first part of this thesis is a literature study into the applications of diatom frustules. The second part is FE-analysis of micromechanical testing of diatom frustules undertaken at NTNU. The models are based on SEM-images of the specimens before and after testing. The simulations are initially run under an assumed young’s modulus, the young’s modulus is then modified until the displacement of the real and virtual tests yield identical results. Two distinct tests are analyzed in this thesis, a cantilever bending test (CBT) and a three-point bending test (TPBT), both on Coscinodiscus sp. frustules. The simulations of the CBT and TPBT returned young’s moduli of 32.8GPa and 36.7GPa, respectively. The returned values for stress varied on the mesh size being used, a mesh size of the 10mm – equivalent to 10nm – returned 3415MPa and 2690MPa for the CBT and TPBT respectively. However, the point of highest stress in the TPBT simulation does not coincide with the fracture in the specimen. Since the results presented in this thesis are based on only two models, the dataset is insufficient to draw any conclusions as to the mechanical properties of the material. Further mechanical tests should be performed, with the purpose of analyzing the results using FE-tools. By documenting the geometry of the specimens thoroughly prior to testing, more accurate models can be made