ABSTRACT
Objective To construct a three-dimensional finite element model to investigate the biomechanical mechanism of carotid blast injuries.Methods Based on the head and neck CT angiography data of a healthy male volunteer,the 3D geometric model was extracted by Mimics software.The 3D solid model was obtained by fitting the geometric model to the non-uniform rational B-splines (NURBS) by Geomagic Studio software.The mesh of blood vessels,blood and soft tissue was divided by HyperMesh software to obtain the three-dimensional finite element model of the carotid artery.The material parameters and boundary conditions were set,and the vessel wall rupture damage threshold was 1 MPa.The dynamic process of carotid injury caused by MK3A2 grenade explosion shock wave at the distance of 60,70 and 80 cm to the neck was simulated using the LS-DYNA,generating the shock waveform and peak overpressure.The stress cloud map was used to analyze the stress distribution and damage morphology,and the stress curve was used to analyze the mechanical changes.Results The peak values of shock wave overpressure were 0.45,0.63 and 0.96 MPa at the distance of 80,70 and 60 cm away from the explosion center,respectively.At 80 cm,the peak stress of vessel wall was 0.43 MPa,and the vessel wall was not ruptured;at 70 cm,the peak stress of anonyma was greater than 1 MPa,which resulted in small rupture;at 60 cm,the peak stress of both anonyma the ascending aorta were greater than 1 MPa,leading to obvious rupture.The root part of the common carotid artery,anonyma and the arch of the aorta were high stress concentration areas,manifested as high-prevalence areas of damage and rupture.Conclusions The finite element model of explosive carotid artery injury is successfully constructed,which can be used to analyze the mechanical response and damage mechanism of carotid blast injuries.The main cause of injury and rupture is that the sudden change of stress in the process of explosion shock reaches or exceeds the threshold of vascular wall injury.Carotid artery rupture will occur when the vessel wall stress peak is greater than 1 MPa at 60 and 70 cm away from the explosion center,providing references for the clinical treatment and injury prevention.