低温冷冻下颅脑热-力耦合分析OA北大核心CSTPCD

Although the brain is the most important organ in the human body,its thermo-mechanical coupling mechanism during cryogenic freezing remains unclear.A thermo-mechanical model for the cryogenic freezing of brain tissue was established,considering the special shape of the skull and brain,the cerebrospinal fluid,the cranial constraints,and the frost-heave effects.Analyses of the temperature field,the phase field,and the pres-sure field caused by the frost heave of the cerebrospinal fluid during freezing show that,the temperature of the cerebrospinal fluid remains unchanged during coagulation,while the maximum temperature difference within the brain tissue could reach 20 K.The solid-liquid phase interface is about 0.3 mm thick,and the driving veloci-ty is about 0.09 mm/s.The maximum displacement of the brain tissue due to freezing is about 0.12 mm near the skull,and the pressure gradient at the solid-liquid interface is as high as 500 MPa/mm,while the pressure in-side the solid and the CSF keeps almost unchanged.This study provides a theoretical support for the human brain cryopreservation strategy and the brain protection.