Local Newton For SuperElasticity Material

[Hoangn06]

Hello,

I would like to ask a question related to the local Newton for the SuperElasticity Material to find the Martensite's Fraction. In 4C, it seemed that the person who programmed this material used a damped Newton instead of pure Newton. I want to ask if there is someone here know about this material and can tell me if the choice of damped Newton is intentional or not? Why not using the pure Newton instead?

Thank you and have a nice day

[mayrmt]

@4C-multiphysics/developers

[amgebauer]

Hi @Hoangn06,

Are you talking about the superelastic shape-memory-alloy material (MAT_Struct_SuperElastSMA) in 4C?

The damped Newton algorithm is more stable in finding solutions for nonlinear equations. The material model in question exhibits strong nonlinear effects once the load exceeds certain thresholds. I suspect that the standard Newton method was not sufficient for solving the local nonlinear equations reliably.