Analysis Of Mechanical Properties And Physical Modeling Of True Vascular Tissue

The cardiovascular disease has become the major killer of human health and its morbidity and mortality has increased year by year.Vascular intervention is the main diagnostic methods and how to improve the level of clinical intervention in the doctor’s surgery is an important step of rising diagnosis and treatment level of cardiovascular disease.Virtual vascular intervention training system has become an effective way for training doctors with the innovation of virtual simulation technology,which has huge advantage of low cost,no damage,repeatability and can be specified.The key points of the virtual vascular intervention system are the real-time and the accuracy of the simulation.However,the traditional physical modeling training system did not considered the elasticity of the blood vessels,and there was no further research on the puncture mechanics of the vessel wall after the interventional guide.Whereas,the main contents of this paper include the following three points:Firstly,the obtaining of physical parameters based on the experiments of real blood vessels.Blood vessels has complicate physical characteristic.In order to obtain the accurate elastic modulus of the blood vessel,the axial stretching experiment of the real blood vessel was designed.The least squares method was used to fit the stress-strain curve under the small deformation of the blood vessel.Then the elastic modulus value of the blood vessel was calculated.Secondly,the mechanical behavior of the vessel wall under different angles of puncture was analyzed,a rule was discovered and a new mathematical model was achieved.In this paper,a large number of experiments were carried out on the real cardiovascular vessels.The mechanical behavior of the probe puncturing the blood vessels with angles of 15°,30°,45°,60° and 90° was analyzed.The approximate linear model of different puncture angle was obtained,which provided a data basis for the establishment of a vascular interventional surgical system.Thirdly,the vascular physical model based on a particle-based spring system was established.In this paper,an equivalent model was proposed by using the elastic modulus measured from real blood vessels.The relationship between the elastic modulus(E)of the real blood vessel and the elasticity coefficient(K)in the particle-spring system was obtained.And a physical model of complex vascular tissue was established to improve the real-time interaction.In the experimental simulation,the finite element model of blood vessel was used to simulate the mechanical behavior of the vessel wall under different angle puncture.It was found that when the probe penetrated the inner wall of the vessel lead to the local deformation of the blood vessel,the mechanical analysis results were similar with the force deformation results of the isotropic modeling.As the results,the similarities can be approximately fitted by a straight line,and the elasticity coefficient decreases with the angle increases.The accuracy basically accommodates the requirements of the virtual surgery and the error is within the range of the permissible error.By comparing the finite element simulation,the proposed model in this paper has improved the simulation accuracy while satisfying the real-time constraints.