Research On Mechanical Experiment And Physical Modeling Of Liver Soft Tissue

Research on the mechanical properties of soft tissues is of great practical significance.Due to the complexity of the mechanical properties of soft tissue,existing experimental research and mechanical and physical modeling of soft tissue have some shortcomings.In view of these shortcomings,this paper proposes from the three aspects of soft tissue uniaxial compression experimental research and physical modeling,puncture experimental research and physical modeling,as well as three-dimensional compression experimental research and physical modeling,the experimental method of optimization or the method of physical modeling is improved.Taking the liver samples of pigs as experimental subjects,the soft tissue samples are subjected to unconstrained uniaxial compression experiments,puncture experiments and three-dimensional printing experiments.Based on the force data obtained in the soft tissue mechanics experiments,the physical modeling of soft tissue mechanics is carried out.This verifies the effectiveness of using the proposed improved method.Aiming at the problem of additional load force in soft tissue unconstrained uniaxial compression experiments,the traditional Ogden superelastic constitutive model is modified,and the natural height of the sample is processed as the parameters to be solved to realize the geometric correction of the model,the gravity stress response is also taking into account the model.The unconstrained uniaxial compression experiment is carried out on the experimental samples.The traditional model and the improved model are fitted to the curve based on the experimental data,and the effectiveness of the proposed correction method is verified.Aiming at the problem of model parameter acquisition method in soft tissue puncture experiment,based on intelligent algorithm,the parameter inversion method of soft tissue mechanics model is written.Matlab was used to call ABAQUS to obtain the physical model parameters for puncture experimental data,combined with comparative experimental data.Finite element simulation proves the effectiveness of the proposed parameter inversion method.Aiming at the complex structure and high cost of soft tissue three-dimensional experimental measurement platform,a new three-dimensional force measurement experiment system is built based on Omni main hand robot and tension sensor,and a new method for the calibration of the end rod length in the system is proposed.The rod length fitting method,which takes into account the influence of eccentricity,has a higher fitting accuracy than the traditional spherical fitting method.Aiming at the problem of 3D geometric model reconstruction of soft tissue,a new geometric reconstruction method is proposed and its reconstruction accuracy is verified.The3 D pressure measurement experiment of soft tissue was carried out using the constructed 3D force measurement platform.The experimental data was carried out using HGO model.Modeling,and verifying the effectiveness of the experimental method and the physical model by comparing the error between the finite element simulation results and the experimental results.