Msc. Patran pcl handbook In a Nutshell 7

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Appendix A

Built-in Function Examples

Appendix A

Documentation for a typical MSC.Patran built-in function.

db_get_nodes(num_nodes, node_ids, rcids, acids, global_xyz)

This function gets nodal coordinate frames and coordinates for the requested nodes.

Input
INTEGER	num_nodes	Number of nodes to get information for
INTEGER ARRAY	node_ids(num_nodes)	Node Ids of nodes to get information for
Output
INTEGER ARRAY	rcids(num_nodes)	Reference coordinate frame Ids
INTEGER ARRAY	acids(num_nodes)	Analysis coordinate frame Ids
REAL ARRAY	global_xyz(num_nodes, 3)	Global coordinates for each node
INTEGER		The function returns a value of 0 when executed successfully and a non-zero value to indicate a change in status or an error

Notes: The C name differs. It is DbFGetNodes.

int DbFGetNodes(num_nodes, node_ids, rcids, acids, global_xyz)
int num_nodes

int *node_ids

int *rcids

int *acids

float *global_xyz
Appendix A

To get all the nodes and their global coordinates

INTEGER NumNodes, NodeIds(VIRTUAL), rcids(VIRTUAL), acids(VIRTUAL)

REAL NodeXYZ(VIRTUAL)
db_count_nodes(NumNodes)

IF (NumNodes == 0) THEN RETURN –1
sys_allocate_array(NodeIds, 1, NumNodes)
db_get_node_ids(NumNodes, NodeIds)
sys_allocate_array(rcids, 1, NumNodes)

sys_allocate_array(acids, 1, NumNodes)

sys_allocate_array(NodeXYZ, 1, NumNodes, 1, 3)
db_get_nodes(NumNodes, NodeIds, rcids, acids, NodeXYZ)

Essentially, the MSC.Patran database is comprised of a series of tables. Hence, the db_get_nodes() function is simply accessing data from a nodal data table, i.e.,

Node ID	RC RCID	AC ACID	X	Y	Z
2	0	0	0.00	0.00	0.00
5	0	2	5.12	-6.34	4.90
25	1	1	56.20	9.01	-1.10

Appendix A

To get the topology of every element

INTEGER NumElms, ElmIds(VIRTUAL), ElmTopoCodes(VIRTUAL)
db_count_elems(NumElms)
IF (NumElms == 0) THEN RETURN –1
sys_allocate_array(ElmIds, 1, NumElms)

sys_allocate_array(ElmTopoCodes, 1, NumElms)
db_get_elem_ids(NumElms, ElmIds)
db_get_elem_etop(NumElms, ElmIds, ElmTopoCodes)
An element’s topology is a term used to describe the combination of the element’s shape and the number of nodes used to define the element connectivity, i.e., 4-node and 8-node quadrilateral elements have the same shape but have different topologies.

To determine the MSC.Patran topology Ids for a particular element shape and connectivity, use the fem_get_patran25_etop() function, i.e.,

INTEGER ShapeCode, NumNodesPerElm, ElmTopoCode
fem_get_patran25_etop(ShapeCode, NumNodesPerElm, ElmTopoCode)

Elm Shape	Shape Code	Elm Shape	Shape Code
Point	1	Tet	5
Bar	2	Pyramid	NA
Tria	3	Wedge	7
Quad	4	Hex	8

Appendix A

To get the shape of every element

INTEGER NumElms, ElmIds(VIRTUAL), ElmTopoCodes(VIRTUAL)

INTEGER ElmShapeCodes(VIRTUAL), NumNodesPerElm(VIRTUAL)

db_count_elems(NumElms)

IF (NumElms == 0) THEN RETURN –1

sys_allocate_array(ElmIds, 1, NumElms)

sys_allocate_array(ElmTopoCodes, 1, NumElms)

db_get_elem_ids(NumElms, ElmIds)

db_get_elem_etop(NumElms, ElmIds, ElmTopoCodes)

sys_allocate_array(ElmShapeCodes, 1, NumElms)

sys_allocate_array(NumNodesPerElm, 1, NumElms)

db_get_elem_topology_data(NumElms, ElmTopoCodes, ElmShapeCodes, @

NumNodesPerElm)

Appendix A

To get all the element connectivity for all elements

INTEGER NumElms, ElmIds(VIRTUAL), ElmTopoCodes(VIRTUAL)

INTEGER ElmShapeCodes(VIRTUAL), NumNodesPerElm(VIRTUAL)

INTEGER MaxNodesPerElm, ElmConnect(VIRTUAL)

db_count_elems(NumElms)

IF (NumElms == 0) THEN RETURN –1

sys_allocate_array(ElmIds, 1, NumElms)

sys_allocate_array(ElmTopoCodes, 1, NumElms)

sys_allocate_array(ElmShapeCodes, 1, NumElms)

sys_allocate_array(NumNodesPerElm, 1, NumElms)

db_get_elem_ids(NumElms, ElmIds)

db_get_elem_etop(NumElms, ElmIds, ElmTopoCodes)

db_get_elem_topology_data(NumElms, ElmTopoCodes, ElmShapeCodes, @

NumNodesPerElm)

sys_free_array(ElmTopoCodes)

sys_free_array(ElmShapeCodes)

mth_sort(NumNodesPerElm, FALSE, NumElms)

MaxNodesPerElm = NumNodesPerElm(NumElms)

sys_free_array(NumNodesPerElm)

sys_allocate_array(ElmConnect, 1, NumElms, 1, MaxNodesPerElm)

db_get_nodes_for_elems(NumElms, MaxNodesPerElm, ElmIds, @

ElmConnect)
Appendix A

To get the elements associated to a particular element property set

FUNCTION GetElmsForPropSet(MyPropertySetName, NumElms, ElmIds)
INTEGER i

INTEGER NumElms, ElmIds()

INTEGER NumRegions, RegionIds(VIRTUAL)

INTEGER MyRegionId
LOGICAL match
STRING MyPropertySetName[]

STRING RegionNames[32](VIRTUAL)
db_count_region_ids(NumRegions)
sys_allocate_array(RegionNames, 1, NumRegions)

sys_allocate_array(RegionIds, 1, NumRegions)
db_get_region_ids_and_names(NumRegions, RegionIds, RegionNames)
match = FALSE

FOR (i = 1 to NumRegions)

IF (str_equal(MyPropertySetName, RegionNames(i))) THEN

match = TRUE

MyRegionId = RegionIds(i)

BREAK

END IF

END FOR
sys_free_array(RegionIds)

sys_free_array(RegionNames)
IF (!match) THEN RETURN –1
db_count_elements_in_region(MyRegionId, NumElms)
IF (NumElms == 0) THEN RETURN –1
sys_allocate_array(ElmIds, 1, NumElms)
db_get_elements_in_region(MyRegionId, NumElms, ElmIds)
RETURN 0
END FUNCTION

Appendix A

To get an element property value (shell thickness) for a specific element

Many people loosely refer to an element property set as simply the element properties. Internally, MSC.Patran distinguishes between the property set and the properties by calling the property set a region. Hence a region is a collection of elements (physical region of the model) and their associated properties (shell thickness, material, orientation, etc.).
FUNCTION get_shell_thickness(ElmId, ElmThick)
INTEGER p

INTEGER ElmId

INTEGER ElmIds(1), ElmRegionIds(1)

INTEGER MaterialId, DataType, IntegerVal, CoordId, NodeId, FieldId

REAL ElmThick, ThickVals(VIRTUAL)

REAL RealVals(3)

STRING CharVal[80]

36 is the property word Id for “thickness”. Other property words and their associated Ids can be found listed in the table of generic property words in Chapter 7 of the PCL and Customization documentation.

ElmIds(1) = ElmId

db_get_region_for_elements(1, ElmIds, ElmRegionIds)
db_count_prop(ElmRegionIds, NumWords)
IF (NumWords == 0) THEN RETURN –1
sys_allocate_array(WordIds, 1, NumWords)

db_get_props_by_region(NumWords, ElmRegionIds, WordIds)

p = mth_array_search(WordIds, 36, FALSE)

IF (p == 0) THEN RETURN –1
db_get_prop_value(ElmRegionIds(1), 36, MaterialId, DataType, @

IntegerVal, RealVals, CharVal, CoordId, NodeId, FieldId)
IF (DataType == 1) THEN /* real scalar at elm centroid */

ElmThick = RealVals(1)

ELSE IF (DataType == -1) THEN /* real scalar field at elm centroid */

MyFunc_EvalScalarFieldCentroid(ElmId, FieldId, ElmThick)

ELSE IF (DataType == -7) THEN /* real scalar field at elm nodes */

MyFunc_EvalScalarFieldNodes(ElmId, FieldId, ElmThick)

E

1

Real scalar at elem centroid

6

List of real values

2

Real vector

7

Real scalar at elem nodes

3

Integer

8

Node reference

4

Character string

9

Coordinate frame reference

5

Material reference

11

Section ID (dimensions)

12

Section ID (properties)

Negative datatypes denote field reference.
LSE

RETURN -1

END IF
RETURN 0
END FUNCTION

Appendix A

There are many other ways to accomplish this same task. The preceding function is very general and very detailed. If the element property set references a field for the shell thickness definition, then functions to evaluate the fields (MyFunc_EvalScalarFieldCentroid() and MyFunc_EvalScalarFieldNodes()) will need to be written. If the shell thickness is only defined at the element centroid, then the ep_word_val_at_el_cen() function can be used. This function has an advantage over the previous example in that this function automatically evaluates any field reference.

FUNCTION get_shell_thickness(ElmId, ElmThick)
INTEGER ElmId, ElmIds(1)

INTEGER NumFoundElms, FoundElmIds(VIRTUAL)

See note on previous page

REAL ElmThick, ThickVals(VIRTUAL)
ElmIds(1) = ElmId
ep_word_val_at_el_cen(36, 1, 1, ElmIds, NumFoundElms, @

FoundElmIds, ThickVals)
IF (NumFoundElms == 0) THEN RETURN -1
p = mth_array_search(FoundElmIds, ElmId, FALSE)

IF (p == 0) THEN RETURN -1
ElmThick = ThickVals(p)
RETURN 0
END FUNCTION

Appendix A

To get a material property value

FUNCTION get_elastic_modulus(MatlName, ElasticModulus)
INTEGER MatlId
REAL ElasticModulus
STRING MatlName[]
db_get_material_id_from_name(MatlName, MatlId)
db_get_matl_prop_value_count(MatlId, NumWords)
IF (NumWords == 0) THEN RETURN –1
sys_allocate_array(WordIds, 1, NumWords)

sys_allocate_array(FieldIds, 1, NumWords)

sys_allocate_array(WordVals, 1, NumWords)
db_get_matl_prop_value(MatlId, WordIds, FieldIds, WordVals)
p = mth_array_search(WordIds, 2, FALSE)

2 is the material property word Id for the Elastic Modulus. Other material property word Ids can be found in the table of Material Property Words in Chapter 7 of the PCL and Customization documentation.

IF (p == 0) THEN RETURN –1

IF (FieldIds(p) != 0) THEN

/* Elastic Modulus is defined

by a field */

ELSE

ElasticModulus = WordVals(p)

END IF
RETURN 0
END FUNCTION
An alternate method of extracting the Elastic Modulus for a material makes use of the db_get_matl_prop_value2() function. The advantage of using this function is that it will automatically evaluate any field references.

Appendix A

To get a list of all groups

INTEGER NumGroups
STRING GroupNames[32](VIRTUAL)
ga_group_ngroups_get(NumGroups)
/* There is always at least one group */
sys_allocate_array(GroupNames, 1, NumGroups)
ga_group_groups_get(Group_names)

To get the nodes and elements associated to the current group

INTEGER GroupId

INTEGER NumNodes, NodeIds(VIRTUAL), NumElms, ElmIds(VIRTUAL)
STRING CurrentGroup[32]
ga_group_current_get(CurrentGroup)
db_get_group_id(CurrentGroup, GroupId)
db_count_nodes_in_group(GroupId, NumNodes)
IF (NumNodes > 0) THEN

sys_allocate_array(NodeIds, 1, NumNodes)

db_get_all_node_ids_in_group(NumNodes, GroupId, NodeIds)

END IF
db_count_elems_in_group(GroupId, NumElms)
IF (NumElms > 0) THEN

sys_allocate_array(ElmIds, 1, NumElms)

db_get_elem_ids_in_group(NumElms, GroupId, ElmIds)

END IF
Appendix A

To get result values for specified elements

To access elemental results you need to know:

Element Ids
Resultcase
Result type
Position or Layer
Result quantity
Location within the element
Coordinate reference

Appendix A

Before looking at the PCL command to extract results, let’s correlate items 1-7 with the MSC.Patran result forms. This correlation is not quite one-to-one. However, it hopefully provides a familiar reference.

Appendix A

Element results are calculated at various points within the element depending on the analysis code, element type, etc.
Generally element results are calculated at either the element:
Centroid
Integration or Gauss points
Nodes

Appendix A

Resultcase names are comprised of 2 components, a loadcase name and a subcase name. Each of these has an associated internal Id. These are called the loadcase Id and subcase Id, respectively.

db_get_load_case_title(lc_id, lc_name)

INPUT: lc_id INTEGER

OUTPUT: lc_name STRING

db_get_load_case_id(lc_name, lc_id)

INPUT: lc_name STRING

OUTPUT: lc_id INTEGER

db_get_sub_case_title(lc_id, sc_id, sc_name)

db_get_sub_case_id(lc_id, sc_name, sc_id)

res_utl_get_loadcases(num_rc, lc_ids, num_sc_per_lc)

INPUT: num_rc INTEGER

lc_ids INTEGER ARRAY

OUTPUT: num_sc_per_lc INTEGER ARRAY

res_utl_get_subcases(lc_id, num_sc, sc_ids)

INPUT: lc_id INTEGER

OUTPUT: num_sc INTEGER

sc_ids INTEGER ARRAY

res_data_bulk_get_loadcases(num_rc, lc_ids, sc_ids, @
coordinates, rc_names)

INPUT:

OUTPUT: num_rc INTEGER

lc_ids INTEGER ARRAY

sc_ids INTEGER ARRAY

coordinates INTEGER_ARRAY

rc_names STRING ARRAY
Alternately, many functions refer to the resultcase via a resultcase Id.

res_db_cget_rescases(num_rc, lc_ids, sc_ids, rc_ids)

INPUT: num_rc INTEGER

lc_ids INTEGER ARRAY

sc_ids INTEGER ARRAY

OUTPUT: rc_ids INTEGER ARRYA

Appendix A

Result type names are also comprised ot 2 components, a primary and a secondary label. Each of these has an associated internal Id. These are called the primary label Id and the secondary label Id.

db_get_primary_res_label(prim_id, prim_label)

INPUT: prim_id INTEGER

OUTPUT: prim_label STRING

db_get_primary_res_id(prim_label, prim_id)

INPUT: prim_label STRING

OUTPUT: prim_id INTEGER

db_get_secondary_res_label(prim_id, sec_id, sec_label)

INPUT: prim_id INTEGER

sec_id INTEGER

OUTPUT: sec_label STRING

db_get_secondary_res_id(prim_id, sec_label, sec_id)

INPUT: prim_id INTEGER

sec_label STRING

OUTPUT: sec_id INTEGER

res_data_get_result_names(prim_id, sec_id, @
prim_label, sec_label)

INPUT: prim_id INTEGER

sec_id INTEGER

OUTPUT: prim_label STRING

sec_label STRING

res_data_get_result_ids(prim_label, sec_label, @
prim_id, sec_id)

res_utl_get_result_ids(num_rc, lc_ids, sc_ids, @
num_res, prim_ids, sec_ids)

INPUT: num_rc INTEGER

lc_ids INTEGER ARRAY

sc_ids INTEGER ARRAY

OUTPUT: num_res INTEGER

prim_ids INTEGER ARRAY

sec_ids INTEGER ARRAY

Appendix A

Alternately, some functions refer to the result type via the result type Id instead of the primary and secondary Ids

rt_id = vki_db_getresid(lc_id, prim_id, sec_id)

INPUT: lc_id INTEGER

prim_id INTEGER

sec_id INTEGER

OUTPUT: rt_id INTEGER

res_data_get_restype_ids(rt_id, prim_id, sec_id)

INPUT: rt_id INTEGER

OUTPUT: prim_id NTEGER

sec_id INTEGER
Layers or positions can be accessed via the following functions

res_utl_get_result_types(res_ids, num_layers, @
layer_ids, layer_labels)

INPUT: res_ids(4) INTEGER ARRAY, lc_id, sc_id, prim_id, sec_id

OUTPUT: num_layers INTEGER

layer_ids INTEGER ARRAY

layer_labels STRING ARRAY

res_data_get_layerpos_name(layer_id, layer_name)

INPUT: layer_id INTEGER

OUTPUT: layer_name STRING

res_data_get_layerpos_id(layer_name, layer_id)

Appendix A

Following is a description of the function used to extract element results. Similar functions exist for extracting nodal results and/or creating either element or nodal results.

res_utl_extract_elem_results(ResIds, ElmList, Derivation, Location, @

CID, DataType, ResLoc, Nres, Ids, @

Nresults, ResVals, MinLoc, MaxLoc)

INPUT
INTEGER	ResIds(5)	MSC.Patran internal loadcase ID, subcase ID, primary result ID, secondary result ID, and layer ID.
STRING	ElmList[]	List of elements to extract results for.
STRING	Derivation[10]	Derivation specifier if the results are to be derived, i.e., VONM, MAJOR, etc. A null value (“”) will leave the result as is.
STRING	Location[]	Location at which to extract the results. Null (“”) or “A”=as is, “C”=element centroid, and “N”=element nodes.
STRING	CID[]	Coordinate system for vector and tensor transformations. A null string (“”) is used to leave the coordinate specification as is.

OUTPUT
INTEGER	DataType	Datatype for extracted results. Valid values are: 1=scalar, 2=vector, and 3=tensor. Note that the Derivation parameter determines what this value should be, i.e., if the Derivation is “VONM” for the VonMises stress then the DataType will be 1 for a scalar value.
INTEGER	ResLoc	Location within the element for the extracted results. Valid values are: 1=centroid, 2=nodal, and 3=multiple. Note that the Location parameter essentially determines what this value should be. If the Location is specified as “C” for centroid, then the ResLoc parameter should return as 1. ResLoc is most useful if the requested Location is “A” or “As is”. In this case, ResLoc will indicate where MSC.Patran has results stored for this particular set of elements, i.e., if Location=”A” and ResLoc=2 then you know that these elements have element nodal results.
INTEGER	Nres	Number of returned element identifiers
INTEGER	Ids(VIRTUAL)	Array of element identifiers
INTEGER	Nresults(VIRTUAL)	Number of results per element
REAL	ResVals(VIRTUAL)	Result values at the specified element locations
INTEGER	MinLoc(12)	Offsets within the ResVals array for each minimum result component.
INTEGER	MaxLoc(12)	Offsets within the ResVals array for each maximum result component.

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