creighbm
Mechanical
- Nov 19, 2007
- 24
I have a question about what Beam Theory NASTRAN uses. Here are 2 simple cases that are yielding different results:
Trial 1:
- 2 nodes connected with a beam element
- Fixed at one end, free at the other
- Apply body load
Trial 2:
- 2 nodes connected with a beam same beam element
- Fixed at one end, free at the other
- Apply distributed load along the element (matches body load magnitude and direction)
Both trials yeild the same bending moment but the second trial has a higher deflection. Now the first trial matches the theoretical Bernoull-Euler beam theory, so I am assuming when you apply a body load NASTRAN is assuming a non-slender weightless beam so Timoshenko beam theory would apply. Is this correct? Is there a simply closed form solution to Timoshenko's beam theory (I have solved the 2 pde's but it's an ugly solution). Thanks for any help.
Trial 1:
- 2 nodes connected with a beam element
- Fixed at one end, free at the other
- Apply body load
Trial 2:
- 2 nodes connected with a beam same beam element
- Fixed at one end, free at the other
- Apply distributed load along the element (matches body load magnitude and direction)
Both trials yeild the same bending moment but the second trial has a higher deflection. Now the first trial matches the theoretical Bernoull-Euler beam theory, so I am assuming when you apply a body load NASTRAN is assuming a non-slender weightless beam so Timoshenko beam theory would apply. Is this correct? Is there a simply closed form solution to Timoshenko's beam theory (I have solved the 2 pde's but it's an ugly solution). Thanks for any help.
