Talk:Nonlinear finite elements/Newton method for axial bar

where are the reduced set of equations for this example developed?

Issue with sign in stiffness matrix?
The stress is defined as E(1+du/dx)du/dx, whereas the MATLAB code at the end has ``sig = E0*(1-eps)*eps''. The constant multiplying the tangent stiffness matrix is AE0/h^2(h+2u2-2u1) which is consistent with the code definition. May be this typo should be corrected in the stress definition?103.21.127.10 (discuss) 10:14, 21 November 2022 (UTC)