Theoretical Study On Vibration Model Of Elliptical Vocal

The language is the most frequent and the most basic communication of humans using, voice is the condition of mutual exchange and communication between human beings. Voice is used more frequent in our occupations and daily life, so good voice for us is an important factor to ensure our career’s development. With the continuous improvement of people’s living standard, Higher and better quality of voice are wished; better voice and better sound are wanted. On the contrary, with the disease of vocal organs and the increase incidence in voice, not only should it cause people physical’s discomfort and psychological damage, but also it will bring the great inconveniences and the serious influences for our work and life. Especially someone who using voice as occupation my even fall into vicious circle. The good sound system is the essential condition of the voice, and the voice system of human include mainly the power organs (such as the respiratory system, the lungs etc.), the vibration organs (vocal), the apparatus (such as the chest, the oral, the nasal cavity, the pharynx etc.), vocal is the core organs and physiological basis of the human’s sound, The vocal cords locate in the throat of human’s body; it has a layered vibration body of composite structure and its vibration characteristics are decided by physiological structure.This article’s researched on human vocal cords. According to its physiological characteristics, the physical model is established, that is to say the oval vocal cord vibration model. Using the piston vibration theory we deduced the spatial distribution of radiation sound field, the acoustic parameters’(such as the sound radiation pressure, the directive property, the radiation impedance etc.) expression of radiation sound field of oval vocal cord vibration model, and using the computer simulation software we simulated, and evaluated the acoustic characteristics of vocal cord vibration model to move forward a single step. It will be the certain reference value that researching the vibration mechanism, the pathological diagnosis and the treatment of vocal cords in the next step. The main contents of this paper are as follows:Firstly, this paper is the contents of physical characteristics of the sound, the principle of sound, the sound power system, the Physiological structure of vocal cord, the function of resonance cavity, etc.Secondly, we put forward and established the oval vocal cord vibration model according to the physiological structure of vocal cord.Thirdly, we researched the distribution of radiation pressure in space. Basing on the vibration theory of piston sound and the characteristics of the establishment of oval vocal cord, we discussed respectively the two cases that normal vocal cord and the pathology vocal cords (such as the unilateral vocal cord polyp), the distribution of radiation pressure in space of oval vocal cord is simulated by using the MATLAB at last. Further analysis, we completed the relationship of radiation pressure and the vibration frequency, the location of space, the hole size of oval vocal cord.Fourthly, according to the radiation impedance’s definition of piston acoustic source, using the micro element method, and building up the mathematical model, author deduced the four heavy integral expression of radiation impedance of oval vocal cord vibration produced. And using the numerical integral method of five node gauss we obtained the radiation impedance’s numerical solution of oval vocal cord vibration produced. Finally, we have researched the relationship between those parameters of oval vocal cord vibration model and the radiation impedance, by the way those parameters are the vibration frequency (wave number), the hole size, the length of oval vocal cord vibration model.