The lengths of the sides of the trapezoid were determined based on simple trigonometric
relationships (see Fig 8-7).
Figure 8-6. Micro column assumed cross sectional shape
From Fig. 8-7 the length X, in terms of its distance from the center of the cylinder
(r,) and the longitudinal crack spacing (0) was expressed as follows:
Xi = 2.ri. sin(0) (8-2)
2
Figure 8-7. Determining the length of the side of the trapezoid using trigonometry