Program HOLES

The Savin solution for the stresses induced near an elliptical hole in a symmetric laminate by in-plane loads are implemented in this program. This solution is discussed in Chapter 9 of the 2^nd edition (this topic does not appear in the 1^st edition).

Program HOLES should be downloaded and saved to a convenient folder on your computer. Once the program is initiated it will ask whether you wish to read several input values “FROM A FILE? (Y/N)” If you enter a “Y” (or “y”, meaning “yes”) the program will search for a file containing the needed information. If the file is not found you will be directed to enter the values from the keyboard.

During execution program HOLES creates the following four files:

(a) DEFINE.txt: This file contains a summary of the data input by the user (which defines the problem being considered) as well as the characteristic equation and principal and secondary roots of this equation.

(b) CIRCUM.txt: This file contains the stresses predicted to occur along the perimeter of the hole. Information written to this file includes (refer to Figure 9.2):

(i) angle a,

(ii) the x- and y- coordinates corresponding to angle a,

(iii) stresses relative to the x-y coordinate system (s_xx, s_yy, t_xy) induced at each point along the perimeter, specified by the (x,y) coordinates,

(iv) the corresponding circumferential stress, and

(v) angle F

(c) XAXIS.txt: This file contains the stresses (s_xx, s_yy, t_xy) predicted to occur along the x-axis (in both the positive and negative x-directions), starting at the edge of the hole and extending to ±10x the hole diameter.

(d) YAXIS.txt: This file contains the stresses (s_xx, s_yy, t_xy) predicted to occur along the y-axis (in both the positive and negative y-directions), starting at the edge of the hole and extending to ±10x the hole diameter.

All four files are stored in the folder that contains program HOLES.

Warning: The user must input all values using a consistent system of units. For example, using the SI system of units a typical value of Young’s modulus might be 200 GPa = 200 x 10⁹ N/m², a typical ply thickness might be 0.125 mm, and the major diameters of an elliptical hole might be 20 mm and 35 mm along the x- and y-axes, respectively. These values would be input as 200.0E9, 0.000125, 0.020, and 0.035, respectively.