aetherTap
Mechanical
- Jul 11, 2006
- 37
OK all, I have an interesting one for you.
I have a set of bolts threaded into a cylindrical bulkhead. Shown in figure 1, they thread into the bolthead and ultimately make contact with an outer ring face.
A axial tensile load is applied to the assembly, and through constraints, is directed through the ring-to-bolthead contact.
I've set this contact for a frictional pure penalty, adjust to touch, coefficient of 0.1 with an acceptably small pinball radius.
Figures 2 and 3 show the resulting stresses
My question is... The stress concentration on the bolt head seems realistic, although the peak value is awfully high. Can I interpret this to mean that the bolt heads will be dented at the point of contact, and possibly seized? Also, how do I interpret the frictional stress on this bolt head in the form of an approximate equation?
Can I resolve the 2500lbf axial load into a 625lbf load per bolt, then resolve this into 45 degrees (the angle of contact) for a tangential load on the bolt head, and then finally divide that load by the element area? Doing this resulted in around 50,000psi, as opposed to 41000psi in the model. Is that acceptable?
I have a set of bolts threaded into a cylindrical bulkhead. Shown in figure 1, they thread into the bolthead and ultimately make contact with an outer ring face.
A axial tensile load is applied to the assembly, and through constraints, is directed through the ring-to-bolthead contact.
I've set this contact for a frictional pure penalty, adjust to touch, coefficient of 0.1 with an acceptably small pinball radius.
Figures 2 and 3 show the resulting stresses
My question is... The stress concentration on the bolt head seems realistic, although the peak value is awfully high. Can I interpret this to mean that the bolt heads will be dented at the point of contact, and possibly seized? Also, how do I interpret the frictional stress on this bolt head in the form of an approximate equation?
Can I resolve the 2500lbf axial load into a 625lbf load per bolt, then resolve this into 45 degrees (the angle of contact) for a tangential load on the bolt head, and then finally divide that load by the element area? Doing this resulted in around 50,000psi, as opposed to 41000psi in the model. Is that acceptable?