Numerical Modeling Of Biomechanics In The Human Lower Airways

The main physiological function of human respiratory system is the exchange of oxygen and carbon dioxide between the blood and atmosphere, maintenance of atmosphere essential for body metabolism. The physiological processes are closely related to the flow of gas in respiratory tract. Owing to the complex nature of airway structure, numerical simulation method is generally used to the investigation of gas flow within the respiratory tract. So far, many papers of gas flow in respiratory tract and particles movement calculation by fluid dynamics have been reported. However, most of the models are low Reynolds number k-ωmodel and standard k-εmodel, which describe gas flow and particle movement in the Lagrangian framework; geometric model is Weibel model A trachea - bronchus symmetry model, oral - pharynx - larynx - trachea and idealized mouth - throat model. Few reports are the direct use of real data reconstruction of the geometric model of the human body, as well as on normal human breathing air flow on the mechanical impact of the lower respiratory tract numerical model.Numerical models are mainly established using the finite element method (FEM) in biomechanical study. Many researches using FEM are conducted, such as Zhou Xuejun et al. established models including temporomandibular joint three-dimensional finite element model; Lu Jun-peng et al. setted up a structure based on brain anatomy finite element model. In our work, we use FEM by ABAQUS finite element software development platform for the work of the human body under normal breathing air on the mechanical impact of the lower respiratory tract preliminary numerical modeling and simulation analysis. First, we established a simplified model of the lower respiratory tract tracheobronchial in ABAQUS. Then, we initiated the model definition of materials, definition of boundary conditions and load, the grid partition, etc. After the initial procedure, ABAQUS calculates equivalent stress and displacement distribution and outputs visualization results. A preliminary simulation of mechanical behavior is achieved. As the simplified model does not realize the form of lower respiratory tract, we conduct experiments using MIMICS medical software with the help of the Third Military Medical University and establish a true model of human respiratory anatomy. This model and the airway part of the mechanical properties of biological tissue are then input into ABAQUS calculation procedures. ABAQUS transform the respiratory trachea, bronchus into the anatomical model human respiratory tract tracheobronchial physical model. Based on previous findings using simplified model, we initiate the physical model with pre-defined boundary conditions. ABAQUS, afterwards, calculates the model of the human body under normal cyclical breathing air to the lower respiratory tract tracheobronchial pressure and changes in distribution of displacement, and outputs visualization results, achieving the simulation on the mechanical behavior of human respiratory airway. Although this model is designed for the human respiratory tract tracheobronchial biomechanical model, the basic technology platforms and methods are fully applicable to other bio-mechanics research. It is with a wide range of applications.