Four-node quadrilateral element
Shape functions (defined in natural coordinates) $N_{1} = \frac{1}{4}(1 – \xi)(1 – \eta)$ $N_{2} = \frac{1}{4}(1 + \xi)(1 – \eta)$ $N_{3} = \frac{1}{4}(1 + \xi)(1 + \eta)$ $N_{4} = \frac{1}{4}(1 – \xi)(1 + \eta)$ The above shape functions are in fact the Lagrangian interpolation Note that we define the element as a square of size … Read more