DYNASTA
1- Standard load cases when we have weight, temperature, and pressure:
L1 W+T1+P1 (OPE) Operating
L2 W+P1 (SUS) Sustained load case
L3 L1-L2 (EXP)* Expansion load case
* Use the algebraic combination method
2- If we have an operating temperature below ambient in addition to one above ambient we should add another expansion load case as follows:
L1 W+T1+P1 (OPE) Operating
L2 W+T2+P1 (OPE) Operating
L3 W+P1 (SUS) Sustained load case
L4 L1-L3 (EXP) Expansion load case
L5 L2-L3 (EXP) Expansion load case
L6 L2-L1 (EXP) Expansion load case
3- When thermal displacements are generally associated with specific operating conditions. D1 is applied with T1, D2 to T2, and so on. We can build load cases as follow:
L1 W+T1+D1+P1 (OPE)
L2 W+T2+D2+P1 (OPE)
L3 W+P1 (SUS)
L4 L1-L3 (EXP) * effects of D1 and T1
L5 L2-L3 (EXP) * effects of D2 and T2
L6 L1-L2 (EXP) * full expansion stress range
4- If we have a uniform load representing a seismic load, U1.
L1 W+P1+T1 (OPE) Operating
L2 W+P1 (SUS) Sustained load case
L3 W+P1+T1+U1 (OPE) Operating with occasional load
L4 L1-L2 (EXP) Expansion load case
L5 L3-L1 (OCC) Segregated occasional
L6 L2+L5 (OCC) * Occasional code stress case
* use scalar combination method.
5- If we have other occational loads like wind load (WIN1) and force (F1) we also build load cases in the same way
6- When we analyze with spring hangers, recommended load cases are as follows:
L1 W (HGR) (HS *= Rigid) Weight for hanger loads
L2 W+T1+P1 (HGR) (HS * = Ignore) Operating for hanger travel
L3 W+T1+P1+H (OPE) (HS * = As Designed) Operating, hangers included
L4 W+P1+H (SUS) (HS * = As Designed) Sustained load case
L5 L3-L4 (EXP) ** Expansion load case
* HS = Hanger Stiffness
** Use the algebraic combination method
When you use only predefined spring hangers, there is no need for the first two load cases. However, the letter H is still required in the operating and sustained load cases.
