The Analysis Of Mechanical Characteristics And Bionic Design Of Crocodile Skull

The excellent performance of crocodile skull is closely related to its structural characteristics.The influence of structure on mechanical properties and how to apply this special structure to bionic design are worth further exploration.This paper takes the Crocodylus mindorensis' s skull as the research object to analyze the relationship between its mechanical properties and structure,and applies the analysis results to the structural design of the bionic crocodile device for the research purpose.The 3D reconstruction of the complex crocodile skull is carried out by using reverse engineering technology,based on the finite element theory and finite element analysis method,the mechanical properties of its skull structure are analyzed,and using computer technology to extract feature parameters.Finally,the analysis results and the constructed mathematical model are applied to the bionic design.The existing methods and technologies are applied to the study of new objects,and the value of crocodile's biological characteristics is brought into play.The bionic grasping device and the bionic fishing device are designed to expand the application range of the bionic crocodile device.The main research content of this paper is as follows:1.The Geomagic Studio reverse engineering software is used to reconstruct the crocodile skull 3D data.The problems of missing and overlapping caused by scanning are dealt with in polygon stage,and the restored crocodile skull model is named model ?(unfilled).Then,according to the actual hunting situation of the crocodile,the holes in the eye and nose areas are filled defer to the curvature,and the crocodile model has been obtained that recovering the curved surface morphology.It is named model ?(filled),and the deviation of model ? and model ? is compared.Finally,based on NURBS(Non-Uniform Rational B-Splines),the camber stage of model ? and model ? is completed.The results show that the deviation of the two models is mainly filled area,few in the other parts,so the two models can be used for subsequent analysis.2.Based on the FEA theory and the FEA software ANSYS,the mechanical properties of the crocodile skull model and the comparison model are analyzed.According to the characteristics of model ? skeleton structure,a simplified model of model ? skeleton structure is established by using the 3D design software CATIA.Firstly,comparison the static analysis of the reconstructed model ? and model ? under the same conditions.Then,comparing the static analysis of the simplified model ? and model ? under the same conditions.Finally,the hydrodynamic analysis and comparison of the simplified model and crocodile model ? are conducted under the same conditions.Comparing the results,it can arrival at a conclusion that under the same condition compared with other two models,model ? has stronger resistance to deformation ability,the stress distribution is more dispersed,difficult to produce resonance,can provide the basis for later bionic design.3.Using the clipping function of Geomagic Studio,the irregular curved surface and streamlined curve data of model ? are extracted.And The establishment of their mathematical model was completed by using the fitting function in the MATLAB software toolbox.Due to the complexity of constructing irregular surface directly,this paper divides the irregular surface into three parts according to its morphological characteristics.The mathematical model of the three surfaces is constructed by polynomial fitting and three mathematical equations are obtained.The fitted data are extracted and merged into a complete mathematical model for deviation comparison with the original surface.The standard deviation is 0.6825,which is within the acceptable range.The method of polynomial approximation and sinusoidal curve approximation is used to construct the mathematical model of the point cloud data of the curve,and two mathematical equations are obtained.They are compared with the original curve respectively,and the latter model has higher determinant coefficient and smaller error.The mathematical model and equation can be applied to the bionic design.The mathematical model obtained by the latter method has higher determinant coefficient and smaller error.The above mathematical models and equations can be applied to the bionic design.4.Based on the results of mechanical characteristic analysis and the mathematical model,the structure design of the bionic grasping device and the bionic fishing device is carried out by using software CATIA.According to the structure characteristics of crocodile skull and the distribution characteristics of its teeth,the bionic grasping device ? is designed.Based on it,a biomimetic grasping device ? with similar performance is designed to make it lightweight.According to the characteristics of crocodile structure,tooth structure and attack,the bionic garbage salvage device is designed to solve the problems of the existing device which cannot be amphibious,broken,salvaging,filtering and collecting.The above structure design of bionic device has certain practical value and has a good development prospect in the field of bionic robot and water conservancy engineering.