Modeling And Research Of Pressure Ventricular Assist Device

Non-blood contact ventricular assist devices can provide a solution to the shortage of heart donors.Compared with traditional blood-contact ventricular assist devices,non-blood-contact ventricular assist devices can reduce problems such as thrombosis caused by blood-contact ventricular assist devices,reduce the cost of treatment,and simplify the treatment plan.Based on independent research and development of the pressure ventricular assist device as the research object,this thesis establishes finite element model of normal heart,heart failure,heart assisted by pressure ventricular assist device,pressure ventricular assist device,and the coupling of the left ventricle and the circulation of the blood lumped parameter model.And we make the pressure ventricular assist device of physical device.Specific content is as follows:This thesis establishes finite element model of normal heart,heart failure,heart assisted by pressure ventricular assist device,receives heart of cross section,potential diagram,stress variation and volume variation of 0.8s(0.3s systolic)of the cardiac cycle under three different moment,and receives three cases of end systolic volume and pressure parameters.The results show that the pumping capacity and capacity of the heart with heart failure are severely inadequate,and that the use of a pressure ventricular assist device to provide 0.6 atm of pressure to the outer wall of the heart could effectively restore the capacity of the normal heart.Based on the obtained end-systolic volume and pressure parameters,the slope of endsystolic pressure-volume curve is obtained,and the lumped parameter model of the heart(left ventricle)under the conditions of normal heart,heart failure and heart assisted by pressure ventricular assist device is obtained.The lumped parameter model of the heart is coupled with the lumped parameter model of the blood circulation,and the cardiac cycle is set as 0.8s.The hemodynamic data under three conditions are obtained,such as left ventricular pressure,left atrial pressure,aortic pressure,aortic flow,left ventricular volume and left ventricular pressurevolume curve.Results are verified again that the heart pressure of heart failure is insufficient and the pressure ventricular assist device is insufficient,and the cardiac index after the pressure ventricular assist device is in line with the normal heart,and the use of pressure ventricular assist device is feasible.In this thesis,the finite element model of the pressure ventricular assist device is also established.Pressure curves with peak values of 0.4 atm,0.6 atm and 0.8 atm are selected to inflate the pressure ventricular assist device,and the surface displacement diagram and volume change diagram of the pressure ventricular assist device are obtained.The results show that the volume change of pressure ventricular assist device is similar to the volume change of heart assisted by pressure ventricular assist device,which verify the feasibility of pressure ventricular assist device.According to the finite element model of the pressure ventricular assist device,this thesis makes the device,including the production of inflatable air bag,the design of air path,which includes module power supply,single chip microcomputer,solenoid valve and electrical proportional valve controller production,and the selection of each component.Through several experiments,the inflatable airbag is used to squeeze the 3D-printed heart,and the air pressure value of slight extrusion is set as the minimum value,and the air pressure value when the inflatable airbag expand to the limit is set as the maximum value.Based on this,the control program of single-chip computer is set,and the physical system is assembled to complete the purpose of making the pressure ventricular assist device.