Virtual experiments on parts of plants

Due to the complex morphological anatomy of plants, not all material parameters needed for the models in project A01 can be determined from experimental data. Our idea is to use virtual experiments, that menas simulations of representative material sections, to simulate the load-bearing behavior of the tissues and thereby enrich the data obtained with the real experiments. Furthermore, the simulation results have to be compared with the results obtained in the real experiment.

The need for this scientific research, not outlined in the proposal of project A01, has resulted from several detailed discussions between project A03 and project A01. The experiments that can currently be performed within the scope of botany do not yet sufficiently account for the anisotropy of the material. An added benefit of the results of this work will be a valuable information for setting up additional experiments.

The plant stem can be approximately treated as a fiber-reinforced composite. Because of the polymer lignin in the cell walls, fibers and xylem elements have a significantly higher modulus of elasticity than parenchyma and collenchyma (matrix tissues). From the stress-strain diagrams obtained so far, it is evident that the material behavior of the plant specimens is strongly nonlinear. Therefore, a hyperelastic material model will be used to model the fibers and the matrix. Assumptions are made for the unknown parameters.

The following questions are to be investigated: 

• To what extent do the results of the virtual experiments agree with the real material behavior of the plants?
• How does the load-bearing behavior of the plant structures change when varying the fiber volume proportion?
• Which findings of the virtual experiments can be used for carbon-reinforced concrete structures?
• Which proportions of matrix and fibers can be realized in carbon-reinforced concrete structures?