Fracture of Ice - Term Paper Example

Ice consists of hydrogen and oxygen atoms. Water molecule has four nearest neighbors arranged near the vertices of regular tetrahedron centered about the molecule of interest. Oxygen atom of each molecule is strongly covalent bonded to two hydrogen atoms while molecules are weakly hydrogen bonded to each other. Like any other crystalline solid, ice is subject to stress undergoes elastic deformation returning to its original shape when the stress ceases or stops. If the shear stress or force is applied to a sample of ice for a long time, the sample will first deform plastically with permanent alteration of shape or simply change in shape.

Plastic deformation or creep is of rather great importance in the study of glacier flow. It involves generally processes like intra-crystalline gliding in which layers within an ice crystal shear parallel to each other without destroying the continuity. During an ice structure interaction, area of high pressure form (HPZs). The HPZs are not linearly distributed across the area of interaction and varies in intensity and location in respect with time. Their formation is critical in evolution of interaction.

When HPZs form near the edge of an ice sheet, they can precipitate large-scale fracture and sparling events. This hence reduces both load felt by the structure and ice sheet. Formation of the HPZs causes creation of layer damage. This layer contains fine grains that are as a result of a combination of processes such as recrystallization and micro-cracking. Pre-existing flaws within the ice may also play a role in scale effect. In nature, ice contains many flaws which may either be in form of large cracks and leads, entrained air bubbles or dirt and irregular grain size as well as composition.

Point defects- Hydrogen and oxygen appear to have the same diffusion coefficient in ice, implying that the