Research On Microstructure Control Mechanism Of Deformation Evolution

Material reinforcement and toughening provide the basis for structural optimization.However,deformation failure of materials or components often begins inside,and structural evolution and deformation analysis of materials requires strong three-dimensional(3D)characterization.In this paper,combined with SR-CT and DVC,the 3D structure evolution and intermal strain analysis of short fiber reinforced and collagen fiber toughened materials were studied.The necessity of microstructural characterization and 3D strain evolution of materials is discussed.The importance of the two factors is analyzed for the mechanical properties of materials.The combination of SR-CT and DVC is used to study the microstructure control mechanism in the process of material deformation failure.Through the improvement of SR-CT mechanical loading equipment,the effective projection angle is greatly improved,and the correlation analysis of 3D strain and structural evolution is realized.Then,the reinforcement materials(fiber reinforced composites)and toughening materials(antler materials)were studied experimentally.The experimental study on the internal deformation failure mechanism of short fiber reinforced composites was carried out.The coupling between structure distribution and strain evolution is characterized,and the correlation mechanism between structure and strain for material mechanical properties is analyzed.The internal mechanical behavior analysis of bio-porous structure materials is carried out,and the strain concentration and microstructure near the intermal micro-cracks are found.A new phenomenon of evolution is proposed,and the mechanism of damage failure and toughening is proposed.The research contents of this paper are as follows:Firstly,the support components of the SR-CT mechanical loading device are improved,the effective projection is greatly increased,and the basis for the accurate reconstruction of the material microstructure is provided;Correlation analysis of strain and microstructure is made possible by the extraction of the corresponding strain concentration zone and material microstructure,which provides a way to study the strain and microstructure coupling mechanism of material failure process.Secondly,the in situ loading experiment of short fiber composites was carried out.Through microstructure extraction and 3D intermal strain analysis,the correlation study between strain evolution and fiber arrangement in composite failure process is realized.In-depth study on the uneven deformation of fiber reinforced materials was carried out,and the strain concentration phenomenon in specific regions was correlated with the material microstructure.Thirdly,the toughening mechanism of the pores and micro-channels of antler porous structure materials was studied.The crack propagation and the formation of S-shaped crack surface were analyzed by deformation evolution and collagen fiber arrangement.High-resolution(0.33^m/pixel and 0.165nm/pixel)in situ loading experiments on antler samples were carried out.S-shaped crack surface was caused by the special microstructure distribution of the sample.The strain concentration zones at the crack face position are significantly more than other areas.This is because deformation localization leads to the initiation and development of damage,and then the micro-crack growth to form the crack surface.