Study On Multi-scale Damage Mechanical Behavior Of Rice Seedling Stem

Mechanical transplanting of rice seedlings can cause damage to the macro and micro structures of the stems,resulting in a slow return of the transplanted seedlings to green and live barley,affecting the late growth and development of rice seedlings.However,research on mechanical damage caused by mechanical transplanting of rice seedlings is weak,and there is a lack of relevant theoretical basis,data support,and analysis methods.At present,the mechanism of mechanical damage to rice seedling stems is still unclear.Therefore,this article focuses on this issue and conducts research on the biomechanical properties of rice seedling stems,the biomechanical properties of rice seedling stem parenchyma cells,the damage characteristics of rice seedling stem tissue,and biomechanical models.The main research contents and results are as follows:1)Study on the biomechanical characteristics of rice seedling stem.According to the mechanical transplanting process of rice seedlings,the stems of the seedlings are prone to mechanical damage,a 30 day old rice seedling,Chuang Liangyou 4418,was used as the research object.The mechanical characteristic curves of the seedling stem were obtained using radial compression tests,and the macroscopic mechanical parameters such as compressive strength,elastic modulus,yield stress,and damage strain were obtained.The growth status of the seedlings after mechanical damage transplanting was studied;The threedimensional geometric model of the seedling stem was reconstructed using Micro-CT technology and a biomechanical finite element model was established.The macroscopic damage mechanical behavior of the stem was explored through mutual verification of finite element simulation and experiments.2)Study on the biomechanical characteristics of parenchyma cells of rice seedling stem.The elastic modulus,stiffness and cell wall thickness of rice seedling stem parenchyma cells were obtained by atomic force microscopy(AFM)and transmission electron microscopy(TEM);The elastic shell theory was used to deduce the cell expansion,and the finite element simulation and nano indentation test were used to inverse the constitutive parameters of the cell wall,which provided accurate mechanical parameters for establishing the damage mechanics model of parenchyma cells.3)Study on the damage characteristics and biomechanical model of rice seedling stem tissue.The microstructure and related parameters of parenchyma cells of the stems of seedlings after radial compression were analyzed using a self-made optical microscope platform.It was found that the internal microstructure and Parenchyma cells were damaged when the stems were subjected to external extrusion loads;The geometric modeling and finite element model of parenchyma in the cross section of the seedling stem were constructed using the skeletonization method.The micromechanical response and damage behavior of mechanical damage were verified through simulation analog verification.Through a combination of theoretical analysis,finite element simulation,and experiments,the evolution law of multi-scale mechanical damage to rice seedling stems under mechanical stress was explored.The research results provide a theoretical basis for revealing the mechanism of mechanical damage to rice seedling stems and provide accurate and effective analysis methods for the study of multi-scale damage mechanisms in plants.