Caesar II oddity 1

[gregdachs]

I did a little test file in Caesar to get a feel for what the program means by positive and negative moments. My result has only served to completely confuse me.

I laid out an "L" shape, anchored at each end. The legs are on the x and y axis, and both are 15 feet. The simulation heats the pipe from 70 to 700 defrees F. In real life, i am sure this would produce equal and opposite moments about the z axis at the two end nodes. However, in the simulation, displaying the W+T2 condition (Local Element Forces --> Load Case Report), the moment at the far point on the x axis is given as Mz. Much to my confusion, all other moments (the node at the far point on the y axis as well as the nodes in the bends) are all My. Could someone help me out with what i'm not understanding here?

Thanks,
Greg

 

[1974vet]

Greg,
Take a look at the GLOBAL forces and moments in the report section. Your answer should be here. Also check out the online documentation for nomenclature. FX, FY, MZ, etc, are global values (upper case) while fx, fy, mz, etc, (lower case) are local. Again, check the documentation for definition of meaning of local values, as they are dependent on how the element was defined. Knowing this however, you can verify the load values just the same.
D

 

[ApC2Kp]

Gregdachs,
The local element "x" axis for CAESARII is in the direction from beginning node to ending node. The local y and z follow changes of direction with the element x axis. So as 1974vet points out, you need to look at the Global force & moments report. The load case W+T2 will generate additional MZ for the node on X axis (assuming Y is up. Global coordinate axis could be configured for Z up, and gravity would then act in Z axis.) Use the T2 load case and compare end nodes for equal and opposite Global moment loads to ignore weight effects. The local axis is useful for the WRC107 and other local geometry based calculations.

 

[gregdachs]

Thanks guys. Now my answers make sense.

-Greg