InterpolateStress for Nonlinear Materials (Partial Differential Equations Toolbox)

Hello

For those familiar to the topic. How can I use the above line

structuralProperties(structuralmodel,'PoissonsRatio',0.3, ...
                                     'YoungsModulus',210E3);

For nonlinear materials? Means, that I don't have a Young's modulus value.