1. Introduction

Human life has become dependent on plants for the qualities and developments that they provide, which include agriculture, food production, and chemical industry. Plant seeds are one of the most important agricultural materials which affects billions of people. Seeds are the result of sexual reproduction in plants. Seeds are of immense biological and economic importance. They contain protein, carbohydrate, starch, and oil reserves that help in the early stages of growth and development in a plant. These reserves are what make many plant seeds important

© 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.

source for a large proportion of the world's inhabitants. For obtaining the economic effects from the seeds, they must often be subjected to mechanical treatment (manipulation, conveying, separation, hulling, pressing, purification, packaging, etc.). That is why studies of mechanical behavior of seeds are nowadays an important field of science and engineering. The research of how seeds as granular or particulate material are deformed, cracked, or how they flow has big importance for industries as biotechnology, pharmacy, agriculture, or food processing and various nanotechnologies. Results of that research are very important for both proper design of machines or equipment and for technological processes optimization. Current research has shown that seeds mechanical behavior is changing over time within the context of their moisture or oil content, acting forces, geometrical parameters, process of crack formation, porosity, visco-elastic properties, or in connection with the changes in the mutual arrangement or reorganization of the seed layers. The resulting nonlinear mechanical behavior and complex motion or spatial orientation of individual seeds or seed layers are very difficult to study, analyze, describe, and predict. For these scientific and engineering tasks, it is necessary to combine knowledge of basic physical seed characteristics, trivial calculations, modeling with the help of simplified or rheological models, or modeling using numerical methods such as FEM (finite element method) and DEM (discrete element method) and experimentation combined with relevant measurements. Also, special methods utilizing the principle of FEM with variable geometry like FDMs (fictitious domain methods) and IB-BCE (immersed boundary body conformal enrichment) can be applied. Almost all the physical processes can be solved using numerical methods. The difficulty lies in the time-consuming calculation of highly complex and nonlinear problems. In this case, the calculation time can only be reduced by using supercomputers. The following chapter is therefore divided into several sections dealing with descriptive seed properties, seed mechanics principles, rheological models, and advanced modeling of seeds behavior.
