cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Showing results for 
Search instead for 
Did you mean: 

Max Shear Stress Graph or Beam Reaction Force?

Highlighted
Newbie

Max Shear Stress Graph or Beam Reaction Force?

Can any of you Mech Structure Gurus give me please, an explanation of the result window 'Stress / Total / Maximum Shear Stress' that appeared in the 2001 version of Mechanica Structure?

I am trying to make sense of a model that was built built and run to figure out whether its hold down bolts were sufficient for certain G loads.

The model was a simplified shell model of a 'box' that is to be bolted into a 'vehicle'. Spot welds were used to represent the hold down bolts.

When Beam Reaction Forces for the spot welds ( beams) were graphed, and the graphs were used to calculate stresses, they gave results which compare favourably with simple calculated ones.

However........

If graphs of Stress / Total / Maximum Shear Stress/ Beams, using the beam elements (spot welds) were plotted, the graphs showed shear stress values that exceeded calculated shear stess values by a factor of 10 at least.

Here lies the problem. Should I take the shear stresses from the graphs of Stress/ Total / Maximum Shear Stress / Beams or should I use the Beam Resultant Forces and calculate the shear stresses from them?

I searched the PTC web site for info but couldn't find anyrhing.


Thanks Folks

Phil Austin, Mechanical Design Engineer, Mektron Systems Ltd in Bedford in the UK