Research On Optimal Crack Position Of Lotus Seed Based On FEA And Experiment

Lotus seed is rich in protein, fat, mineral elements and so on, which is used as an important herbal medicine and health care. With the raising of living standard and health consciousness, the need of lotus seed increases annually. Therefore, the higher standard is needed in the production and process. However, factors such as small gap between shell and kernel, variety in breed, diversity in size and irregularity in shape enhance the difficulty of cracking shell and fetching kernel. The existing decladding equipment can't adjust incision force according to the hardness of shell, which leads to the imperfect situation in which flesh lotus seed can be cut off easily but dry lotus seed can't be cut. The cracking operation leads to damaged and broken kernels. The extent of damage depends on the physical and mechanical characteristics of its shell and kernel, variety and applied force which is one of the most important factors for cracking lotus seeds. Since currently used systems have been generally designed without taking these criteria into consideration, which leads to inadequate application. It is, therefore, important to test and study their physical and mechanical characteristics and determine the decladding mechanism to find effective method and provide technical data of equipment.According to the understanding of inland and oversea documents on materiel characteristics and threshing technologies of some nuts, the experiment scheme about testing physical and mechanical characteristics is determined, that is, taking size, moisture, starch content, loading velocity, loading position and wedge angle as factors and rupture force and deformation as indexes. The results show that lotus seed is viscoelastic and the correlation between the above indexes and factors is linear or nonlinear.On the base of the above researches, the stress and strain distributions of lotus seed shell are analyzed with three finite element models. The linear load distributed evenly along long axis towards short axis of lotus seed is optimal. At that situation, the trend of stress-strain distribution is beneficial for extending cracks, therefore, threshing efficiently.