Design sensitivity analysis for nonlinear magnetostatic problems by continuum approach

Using the material derivative concept of continuum mechanics and an adjoint variable method, in a 2-dimensional nonlinear magnetostatic system the sensitivity formula is derived in a line integral form along the shape modification interface. The sensitivity coefficients are numerically evaluated from the solutions of state and adjoint variables calculated by the existing standard finite element code. To verify this method, the pole shape design problem of a quadrupole is provided.