Material Mapping

Map one material definition to another material.

In many instances, you may need to analyze a structure with a material having different options (user material constants) associated with the analysis. For example, you may wish to analyze a region around a stress concentration with progressive failure, but only use a linear solution in the region away from the stress concentration to reduce run time. If the same material is to be used for both regions, two different *USER MATERIAL commands must be issued within the Abaqus input file, each corresponding to a different material. Therefore you would need two different materials defined in the materials database, each with exactly the same properties and different names.

Recognizing a need for a better approach, the HIN file contains the capability to map one material name to another using the keyword and data line shown below.

*MAP, FROM=NAME, TO=NAME
FROM, TO

In the definition above, the FROM and TO parameters on the second line allow you to map one material name defined in the Abaqus input file to another material name defined in the Abaqus input file. Using this method, you could specify two different materials in the analysis with different material constants and not have to recreate the base material of interest.

As an example, consider the open hole coupon shown below. Here, it is desired to deactivate progressive failure in the regions away from the stress concentration, which requires two different materials.

The only way to tell Abaqus that different materials are to be used for the two regions is to create two material definitions and assign the materials to the two regions. When used with Helius PFA, each material would have a corresponding *USER MATERIAL card as shown below.

*MATERIAL, name=IM7_8552
*DEPVAR
7
*USER MATERIAL, constants=16
1,1,1,0,0,0,0,0
0,0,0,0.1,0.01,0,0,0

*MATERIAL, name=IM7_8552_NOFAIL
*DEPVAR
7
*USER MATERIAL, constants=16
1,1,0,0,0,0,0,0
0,0,0,0.1,0.01,0,0,0

Note the only differences in the material definitions above are the names the materials and user-material constant 3. In general, any coefficient except the units flag (user-material constant 1) could be changed between the two materials. In a traditional analysis, two different materials would have to be created and stored in the materials database to accommodate the above scenario. This means you would have multiple copies of a single material in the materials database, which is not desirable.

To accommodate the scenario above without forcing you to recreate multiple materials, the HIN file allows you to map one material to another. To map one material to another in the HIN file, the following card should be used.

*MAP, FROM=NAME, TO=NAME
FROM, TO

For this specific example, the card will appear as:

*MAP, FROM=NAME, TO=NAME
IM7_8552_NOFAIL, IM7_8552

Here, all of the static the material properties from material IM7_8552 will be used for material IM7_8552_NOFAIL, while the user material constants (the dynamic material properties) for IM7_8552_NOFAIL will be used as specified in the Abaqus input file.