RESULTS CALCULATE COMBINE Combination_name [Step_number]

            

This command enables the user to scale and combine loadcases.

Combination_name = The name to be given to a new combination loadcase or the name of an existing combination loadcase (See notes 1 and 2).

Step_number = This defines the step number associated with the combination loadcase and may be required when using combinations for non linear or time dependent analysis results.

Notes:

1.

Defining a new combination loadcase
If the combination loadcase does not exist then the user will be prompted for source loadcase names and scale factors alternatively until the keyword `GO' is entered in full; at which point the user will be prompted for a description of the new loadcase and the name of the results attribute(s) to be combined.

2.

Using an existing combination loadcase
If the combination loadcase already exists, then the definition of the combination will be referenced and the user will be prompted for the name of the results attribute(s) to be combined.

3.

Selecting the results attribute(s) to be combined
During the combination procedure, the user will be prompted to specify the attribute(s) to be combined. The list of attributes available for combination are those attributes that exist in the first source loadcase specified in the definition of the combination. In addition, the user may use the keyword CURRENT to request that the current results attribute be combined, or the keyword ALL to request that all the available attributes in the attribute list be combined.

If an attribute that already exists in the combination loadcase is specified then the combination request will be ignored. An error message will be produced and existing attribute data in the combination loadcase will not be overwritten.

An attribute cannot be combined unless it exists in all of the source loadcases specified in the definition of the combination.

4.

Status on command completion
On successful completion of a combination command, the combination loadcase will become the current loadcase. The results attribute and component that become current will depend on which attribute selection was made:

i.

If the attribute was selected from the attribute list then the first component of that attribute will be made current.

ii.

If the CURRENT attribute was selected then the current component of that attribute will remain current.

iii.

If ALL attributes were selected then no attribute will be made current.

5.

Use of combination loadcases
Results stored in combination loadcases may be accessed and presented in the normal way. Combination loadcases may also be used in the definition of other combination loadcases.

6.

Use of combination loadcases with assemblies
It is not currently possible to define and perform a loadcase combination on an assembly model. However, any combination loadcases existing in the models used to create the assembly will exist in the assembly model, and the user should ensure that the definition of the loadcase combination is consistent for each model in the assembly.

7.

Using appropriate data
Users are reminded that the combination of certain types of data is meaningless. Examples are principal or Von Mises stresses and principal strains. If ALL attributes are selected for combination a precautionary warning message to this effect will be given. The user should delete any meaningless attributes from the combined loadcase.

Examples:

1.

RESULTS CALCULATE COMBINE COMB1

The following is an example prompt sequence if `COMB1' is a new combination loadcase:

 SOURCE LOADCASE (OR 'GO') => L1
 SCALING FACTOR => 1.0
 SOURCE LOADCASE (OR 'GO') => L2
 SCALING FACTOR => 2.5
 SOURCE LOADCASE (OR 'GO') => GO
 20 Character Ref => WIND LOAD PLUS DEAD
 ATTRIBUTE => ALL

2.

RESULTS CALCULATE COMBINE COMB2

The following is an example prompt sequence if `COMB2' is an existing combination loadcase:

 ATTRIBUTE => NODAL STRESS