Abstract:

：Structure design and performance analysis of egg-shaped pressure hulls are performed according to geometric properties of eggshells. Shape and size of goose eggs are tested to study roundness, volume, surface area and shape index of these eggshell. Functions of volume, surface area and counter for the eggshell are proposed as well. An egg-shaped pressure hull at a depth of 4 km is designed based on experimental results of eggshell. Furthermore, main properties of the egg-shaped pressure hull are evaluated quantitatively. These properties include safty, buoyancy reserve, interior arrangement and hydrodynamics. Effects of length, width and thickness on the properties of the egg-shaped pressure hull are investigated by orthogonal test design. The results show that goose eggshells are highly symmetrical. The shape index follows a normal distribution with the mean value of 0.69. The egg-shaped pressure hull has superior properties. It is found that the most important influencing factor on the strength is thickness, following is length and the least is width. The most important influencing factor on the buckling is length, following is thickness and the least is width. The most important influencing factor on the buoyancy factor is thickness, following is width and the least is length. The most important influencing factor on the space utilization is length, following is width and the least is thickness. The hydrodynamic characteristics are mainly affected by width.

Key words: egg shape function, eggshell, structure design, pressure hull