Mechanical Analysis Of Human Heart Based On Fluid-structure Interaction

Heart is the most important organ of the human body,providing the main power for blood circulation and maintaining normal life activities.Its biomechanical parameters are important indicators for the functional assessment of the heart and the pathological study,prediction and diagnosis of heart diseases.In recent years,heart diseases have been prevalent year by year,posing a serious threat to human health.Although there are many hemodynamic monitoring methods in clinic that can be used to obtain the biomechanical parameters of the human heart,these traditional methods still have some limitations.In order to obtain the hemodynamic parameters of the human heart more comprehensively and accurately without harming human health,the non-invasive method — numerical simulation has become an effective and feasible choice.In this paper,we use a parallel scalable solver to perform the fluid-structure interaction simulation of the human left ventricle.We firstly reconstruct the 3D geometry of the left ventricle based on the CT medical image data of human heart and establish the fluid-structure interaction mathematical model to describe the myocardium and blood.Then an unstructured tetrahedral mesh is generated for the left ventricle and the corresponding mathematical model is discretized and solved on the mesh.Finally,the simulation results are analyzed and verified.For the mathematical model,this paper uses three-dimensional unsteady incompressible Navier-Stokes equations to describe the blood flow,a linear elastic equation to model the deformation of the myocardium,and then the interaction between blood flow and myocardium is transferred by the velocity and stress interface conditions.For the solution algorithm,a first-order finite element method and a fully implicit backward Euler format are used to discretize the mathematical model in the spatial and temporal directions,respectively,and then a parallel Newton-Krylov-Schwarz algorithm is used to solve the nonlinear equations in each time step to obtain the corresponding mechanical parameters.With the proposed solver,this paper did a patient-specific fluid-structure interaction simulation of human heart with realistic geometry and physical parameters.The numerical results show that we can accurately simulate the mechanical details of the left ventricular myocardium and the blood contained in it by comparing it with the clinical imaging data.In addition,the algorithm has good stability and robustness for the fluidstructure interaction problem considered in this paper,and the algorithm achieved 40%parallel efficiency when the number of processor cores is up to 2300,which indicates that the algorithm has the potential to perform high resolution and fast simulation of the human heart hemodynamics by using a large supercomputer.