Numerical study on the effect of the geometry size of multi-chamber infusion bag on its bursting force / 生物医学工程学杂志

This study explored the variation of bursting force of multi-chamber infusion bag with different geometry size, providing guidance for its optimal design. Models of single-chamber infusion bag with different size were established. The finite element based on fluid cavity method was adopted to calculate the fluid-solid coupling deformation process of infusion bag to obtain corresponding critical bursting force. As a result, we proposed an empirical formula predicting the critical bursting force of one chamber infusion bag with specified geometry size. Besides, a theoretical analysis, which determines the force condition of three chamber infusion bag when falling from high altitude, was conducted. The proportion of force loaded on different chamber was gained. The results indicated that critical bursting force is positively related to the length and width of the chamber, and negatively related to the height of the chamber. While the infusion bag falling, the impact force loaded on each chamber is proportional to the total liquid within it. To raise the critical bursting force of in fusion bag, a greater length and width corresponding to reduced height are recommended considering the volume of liquid needed to be filled in.

The Effect from Elastic Modulus of Vessels on Fractional Flow Reserve of Carotid Artery Stenosis / 医用生物力学

Objective To explore the feasibility of applying fractional flow reserve (FFR) into the assessment of carotid stenosis, and analyze the effects from elastic modulus of vessel wall on hemodynamic parameters of carotid artery stenosis model and FFR calculation results. Methods The standard models of carotid bifurcation and stenosis models with different stenosis rates were established by computer-aided design software. Assuming that the vessel wall was linear elastic material and the blood was incompressible Newtonian fluid, the fluid-structure coupling simulation of blood flow in carotid artery stenosis model under the pulsating flow was carried out by finite element analysis, and the relevant hemodynamic parameters were obtained, and the corresponding FFR was calculated. Results When the elastic modulus was fixed, the FFR for narrow part of the model decreased gradually with the increase of the stenosis rate, and the relative difference between the FFR of elastic wall and rigid wall increased with the increase of the stenosis rate; when the stenosis rate was fixed at 70%, the FFR decreased gradually with the increase of elastic modulus. Conclusions The effect of vascular wall elasticity should be considered in the process of functional assessment on carotid stenosis with FFR; the larger stenosis rate will lead to the greater influence from elastic modulus of vessel wall on FFR.