Using similar notation as Exercise 15.6, show that the strain energy associated with the edge dislocation model of Example 15.1 can be expressed by:

Note that this energy is larger than the value developed for the screw dislocation in Exercise 15.6. Evaluate the difference between these energies for the special case of v = 1/3.

Data from exercise 15.6

Show that the strain energy (per unit length) associated with the screw dislocation model of Example 15.2 is given by:

where R_o is the outer radius of the crystal and R_c is the core radius of the dislocation. This quantity is sometimes referred to as the self-energy. The radial dimensions are somewhat arbitrary, although R_c is sometimes taken as five times the magnitude of the Burgers vector.

Data from example 15.2

Data from example 15.1

Wedge ub 4(1 - V) Ro -log- Re