CALCS BAS016
UNIT CASE COMBINATIONS

NOTATION

Loadid for load recovery
Uiunit load case set id i
IDcombcombined load case set id
Cicombined load case set id

APPLICATION

Structural or mechanical systems in which combinations of scalar factored unit cases are valid, for example, linear static structural analyses
Maximum numbers of: Nloads*Nunitcases 3000, Ncomb*Nunit 1000.

OUTPUT

Combined Loads

SEE ALSO

PROC051

THEORY

Principle of Superposition

GUIDANCE

Only loads of interest are considered rather than resolved loads for each nodal freedom. This strategy minimises zero loads and allows refined load output.
Take care, when entering unit case factors for combined cases interactively, not to commence the data line with the case number, as this is generated by the program.
Analysis Procedure
1. Draw 3D sketch of structure (fig1)
2. Draw disassembled freebody diagram (fig2)
3. On fig2, identify points of effective load application and significant internal load points. Number them 01 to ij. Loads applied to members are suffixed 1to6 to identify local loads.
4. For fig1, construct table NODE:X:Y:Z:MASS and complete using node IDs same as fig2 load IDs.
5. Copy freebody diagrams for unit load cases, for example:
Fig3 Effective point masses at fig2 load points
4 Fx = 1 UNIT ACCELERATION
5 Fy = 1
6 Fz = 1
7 Px @ 50 m/s WIND LOADS
8 PZ
6. Use PROC051 to chase loads thru structure for each unit load case.
To enable one calculation set to be copied and used for another (ex: calcs for Inertia Fx copied for Wind Px) include data lines for external loads rather than writing directly into internal load expressions.
7. Write unit case loads, calculated with PROC051, on unit case figs.
8. Formulate required combined cases and solve with PROC016.

INPUT FORMAT

DAT016title
dataNo.UnitCases
LoadU1U2
tabdelimiteddata
ENDDAT

EXAMPLE

Input

DAT016example
2No.UnitCases
LoadU1U2
1.5-.3
2.5.3
30.5
40.5
IDcombU1U2
12.31.2
2-.931.85
ENDDAT

Output

LoadC1C2
10.79-1.02
21.519E-2
30.60.925
40.60.925
END016