13 



The stress concentration factors for the two sizes of cable penetra- 

 tions without bolt holes based on the theoretical membrane stress were 

 1. 28 for the 0. 358" diameter hole, and 0. 97 for the 0, 144" diameter hole. 

 The location of the maximum stress for each of these two sizes of holes 

 was on the concave surfaces at the hole boundary on the penetration center- 

 line circleo These factors are comparable to the theoretical factor of 2 

 for an infinite plate of uniform thickness with a hole, subjected to a biaxial 

 stress field(6). 



The stress concentration factors for the two sizes of cable penetra- 

 tions with bolt holes, again based on the theoretical membrane stress, 

 were L 21 for the 0. 358" diameter hole, and lo03 for the 0. 144" diameter 

 hole. The location of these maximum stresses correspttnded to the loca- 

 tions of maximum stress for the cable penetrations without bolt holes. 



The stresses around the bolt holes near the 0„ 358" diameter 

 cable penetration were greater than those near the 0. 144" diameter, and 

 the stresses around the bolt holes for either case were less than that at 

 any of the cable pehetrations.- - The bolt hole boundaries were at the same 

 distance from the boundaries of the cable penetrations for both sizes of 

 the penetrations. The stress concentration factors for the cable penetra- 

 tions decrease directly as a function of the ligament efficiency, i, e. , the 

 stress intensity decreases as the distance between the penetration and the 

 bolt holes decreases. 



