Blood flow topology optimization considering a thrombosis model

Author(s)

Alonso, Diego Hayashi ; Nelli Silva, Emilio Carlos

• Document type: Journal article
• Source: STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION; v. 65, n. 6, p. 25-pg., 2022-06-01.

Abstract

In the field of topology optimization for fluid flow design, there is a specific class of formulations directed to non-Newtonian fluids. One prominent case is when the fluid is blood. In this case, in addition to the non-Newtonian effect, the damage caused by the flow to the blood (i.e., blood damage) should be taken into account. Blood damage is essentially given by two types: hemolysis, which corresponds to the breakdown of Red Blood Cells (RBCs), and thrombosis, which corresponds to the formation of blood clotting. More specifically, in terms of thrombosis, blood clotting is formed by the aggregation of platelets and RBCs in vessels. Furthermore, in order to model thrombosis, there are essentially two approaches-platelet activation (initiation of thrombosis) and platelet aggregation. However, the computational cost of the second approach is still considered impractical for real applications. In the topology optimization field, hemolysis and thrombosis have been normally assumed to be indirectly minimized by considering the shear stress (or even energy dissipation or vorticity). However, a recent work has considered the direct minimization of hemolysis from a differential equation model. In terms of thrombosis, the stress levels for damage are 10 times lower than hemolysis, which means that it may not be sufficient to consider only the minimization of hemolysis in the design. Therefore, in this work, the topology optimization is formulated in order to take thrombosis into account, computed by a platelet activation model. The resulting formulation is also set to consider hemolysis and relative energy dissipation (as a way to indirectly maximize efficiency). In terms of thrombosis, the shear-induced platelet activation model is here rewritten for a finite elements approach, while also considering the necessary adjustments for the topology optimization formulation. The topology optimization is also formulated for a non-Newtonian fluid model for blood, and the optimization solver is IPOPT (Interior Point Optimization algorithm). Some numerical examples are presented considering 2D swirl flow configurations and a 2D configuration. (AU)

• FAPESP's process: 17/27049-0 - Topology optimization method applied to the design of rotor and volute of ventricular assist devices based on the viscosity effect (Tesla principle)
• Grantee: Diego Hayashi Alonso
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 14/50279-4 - Brasil Research Centre for Gas Innovation
• Grantee: Julio Romano Meneghini
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 13/24434-0 - Electromagnetic propeller systems for implantable artificial heart and mechanical circulatory support devices
• Grantee: José Roberto Cardoso
• Support Opportunities: Research Projects - Thematic Grants