Research On Physical Property Test And Modeling Method Of Mature Rice Plants

In this paper, first, the of rice plants physical modeling method is studied. Then, the morphological characteristics of the of rice plants were observed and measured to obtain the relationship between morphological parameters, position, species, moisture content influence on the breaking force of rice panicle, stiffness coefficient is studied, a method of rice plants physical model was introduced. The main work is as follows:(1) Morphology, structure, characteristics of Tigeng and Bohe rice plants are observed, stem, leaf sheath, leaf, panicle were measured, samples of a series of morphological parameters was obtained. Combined with the results of previous studies, the relationship between various morphological parameters are as follows:It is power function between internode length and the number of the position of the section (NPS). It is logarithmic function between equivalent diameter and the NPS. It is linear relationship between thickness and the NPS. It is power function between the length of the leaf sheath and the number of the position of the leaf sheath(NPL). It is power function between the ratio of wrapped and the NPL. It is logarithm function between the ratio of the length of leaf sheath and the length of internode and the NPL. It is quadratic function between the ratio of the length of primary branches and the length of rice panicle. It is linear relationship between the number of secondary branches in primary branches and the length of primary branches. It is linear relationship between the number of the primary branches and the number of the grains in the primary branches. It is cubic function between the length of secondary branches and the length of primary branches. It is linear relationship between the number of the grains in the secondary branches and the length of secondary branches. It is quadratic function between the number of grains in the secondary branches in the same panicle knot. With the increasing of the volume of the grain, the ratio of grain length and grain thickness stay stable and the ratio of grain width and grain thickness increased.(2)These junctions are tested in the Universal Testing Machine-the junction between the grain in the primary branches and the spike branches, the junction between the grain in the secondary branches and the spike branches, the junction between the spike branches and the primary branches, the junction between the primary branches and secondary branches, the junction between the primary branches and the rachis of the panicle. And position, species and moisture content are considered to influence the breaking force and stiffness coefficient. The main conclusions are as follows:① Define position coefficients to study how position influences the breaking force and stiffness coefficient. Along the rachis of the panicle from the bottom to the top, the breaking force between spike branches and the grain in the primary branches decreases while the stiffness coefficient increases after the first decreases, the breaking force between spike branches and the grain in the secondary branches slightly decreases while stifffness coefficient stay stable. There is no significant difference between them. Along the rachis of the panicle from the bottom to the top, the breaking force between spike branches and primary branches decreases while stifffness coefficient stay stable, the breaking force between primary branches and secondary branches decreases, the breaking force between the primary branches and the rachis decreases after first increases while stifffness coefficient decreases after the first increases and then increases again. In general, the breaking force between spike branches and the grain in the primary or secondary branches< the breaking force between spike branches and primary branches< the breaking force between primary branches and secondary branches< he breaking force between the primary branches and the rachis.② Jigeng, Bohe, Nongda and Tongdao rice are tested. The braking forces of Tongdao are generally smaller, but the braking forces of the junction between the primary branches and the spike branches are much higher than the other three spicies. Similar law for the stiffness coefficient is Jigeng>Tongdao>Nongda>Bohe.③ The moisture content investigated in this paper are 2.403%,11.652%,12.749%, 17.868%,20.033%,24.878%, through rice varieties, the conclusions are as follows:In the test range, with increasing moisture content, the breaking force between spike branches and the grain in the primary branches increases after the first decrease, the stifffness coefficient decreases, the breaking force between spike branches and the grain in the secondary branches increases and the stifffness coefficient stayed stable. Both the curve of the breaking force between spike branches and primary branches and the curve of the stifffness coefficient are twin peaks inverted with the increasing moisture content. The curve of the breaking force between primary branches and secondary branches is twin peaks while curve of the stifffness coefficient is twin peaks inverted with the increasing moisture content. With the increasing moisture content, the breaking force between the primary branches and the rachis of the panicle and the curve of the stiffness coefficient is twin peaks inverted.(3)A method of rice plants physical model was introduced. The geometric model of internode is build with frustum of a cone or ball combination method, so the geometry model of stem is the combination of several internode geometric models. The geometric model of leaf sheath is build with a cylinder which is part left. Distribute several balls on the skeletons which are in the cylinder. Leaf edge curve and leaf vein curve are built with Bezier curves which several balls are distribute on. Branches which include rachis of the panicle, primary branches, secondary branches and spike branches are built with ball combination method while grains are built with nine balls. The panicle of the rice is assembled with branches and grains. Stem and panicle mechanical model is linear viscoelastic mechanical model, leaf and leaf sheaths mechanical model is particle-spring model. when the connection force is bigger than the maximum connection force which is tested, the connection breaks.