I never said the bolts failed in a tensile load case...I merely stated the fact the tensile strength of the bolt was roughly equal to the force on the engine.
If you were going to pick apart something my post why didn't you go for the easy one? The load is shared by 4 bolts!
The joint can fail in several ways...I mentioned 2 likely failure modes and neither of them required the bolt to fail by tensile load case.
For most standard threaded fasteners, shear strength is
not specified even though the fastener may be
commonly used in shear applications. While shear
testing of blind rivets is a well-standardized procedure
that calls for a single shear test fixture, the
shear testing technique for threaded fasteners is
not as well designed. Most procedures use a
double shear fixture, but variations in the test
fixture designs cause a wide scatter in measured
shear strengths (i.e., the variations in test
procedures produce non-standard results).
To determine the shear strength of the
fastener, the total cross-sectional area of the
shear plane is important. For shear planes
through the threads, we could use the thread
root area. There are two possibilities for
applied shear load (as illustrated below). One
possibility is that the shear plane occurs in the
threaded portion of the bolt. Since shear
strength is directly related to the net sectional
area (i.e.: the amount solid bolt material in the
diameter), a narrower area will result in lower
bolt shear strength. To take full advantage of
strength properties the shank of the bolt body
should be within the shear planes. To
illustrate, consider the difference in shear
strength between the two Grade 8 bolts on the
previous page; one with the threads in the
shear plane, the other with the shank in the
Want DP delivered to your inbox daily? Subscribe here: