Levator veli palatini muscle and infeior wall of eustachian tube move from the axis of the tube to outward gradually as increasing with age and overlapping proportion of them was reported.

This paper also presents a method to solve the tunnel axis displacement on line caused by angle error between tube center axis and datum of joint.

This article establish the mechanics model of pendent axis of tube style centrifugal machine, analysis and calculate the fatigue and fracture safety property of pendent axis.