The capability to model piezoresistive effect exists in the following elements:
| PLANE223 - 2-D 8-Node Coupled-Field Solid |
| SOLID226 - 3-D 20-Node Coupled-Field Solid |
| SOLID227 - 3-D 10-Node Coupled-Field Solid |
In piezoresistive materials, stress or strain cause a change of electric resistivity:
 | (10–61) |
where:
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 | (10–62) |
where:
| {r} = vector of matrix [r] components = [rx ry rz rxy ryz rxz]T |
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Similarly, for strains:
 | (10–63) |
where:
[m] = piezoresistive strain matrix (input on TB,PZRS command with TBOPT = 1) |
| {εel} = elastic strain vector |
The coupled-field finite element matrix equation for the piezoresistive analysis is given by:
 | (10–64) |
The terms used in the above equation are explained in Piezoresistive Analysis where the conductivity matrix [Kv] is derived as:
 | (10–65) |