On The Mechanical Model And Stress Analysis For Plant Stem With Core

It's different in physical structure between the plant stem with solid core and that without core.And the former has a special node just like a plate while the latter has a ring-like one. So they have definitely different mechanical properties. Since more and more plant stems will be used in industry and agriculture, it's necessary to study the mechanical properties of them.There are many aspects in studying the mechanical property of plant stems, such as the stability of bending,anti-lodging, etc. In this thesis, sugarcane will be the material we discuss. In order to study the properties of mechanical reaction of sugarcane, we will put it in a transverse compression evenly distributed along the axes of its length.We can get the model for analysis through studying many different kinds of real plant stems. Thus a model with skin, core and node is built. Furthermore, all of the component of the model are anisotropic. If we use the elastic theory and the mechanics of composite material, a very complex partial differential equations of two order will be obtained. After comparing the main method in solving these equations, the author choose finite element method as the best method.The parameters of material are very important for analyzing. By tensile test or compression test, most of the parameters can be attained. Some parameters are difficult to measure, so we have to select them according to other existed results. The least squares criterion is used in the curve so that we can get a more precise result of the range. In addition ,the property of the whole sugarcane is also tested for the sake of comparison with FEM result. The form of fracture is also simply described in this thesis.During the analysis ,some predigests for the structure, restriction and the load should be taken, thus we can get a fairly good result for stress, strain and displacement. Througe describing the effect of different parameters,different load, different restriction, node or nodeless and the distance of the node, we can find they would have different effect on the performance of sugarcane. The code will bring the most obvious effect, and the transverse modulus of core are the second important.The thesis gives a useful reference for how to build model, to analyse, to measure parameters, and how to calculate for different materials and structures.