Lecture
This lecture covers the isoparametric formulation of the Quad4 planar element, explaining the process of calculating stiffness matrix based on the reference element (s, t) rather than specific element cases (x, y). It includes choosing the element, interpolation functions, deriving the stiffness matrix, and finding consistent forces. The lecture also discusses the interpolation functions, matrix Jacobian, gradients calculation, and assembly algorithm for stiffness matrix. Additionally, it explores the physical interpretation of the Jacobian determinant, the algorithm for consistent forces calculation, and the general algorithm for stiffness matrix assembly. The lecture concludes with the explanation of the forces in natural coordinates and the challenges of manual integration in numerical methods.