100 N/mm 5 mm 2 mm 10 mm 20 N/mm X2 X1 Consider the above 2D plane strain linear elastic structural problem. The left side has roller boundary conditions allowing the structure to move only in the x2 direction, while the bottom side has roller boundary conditions allowing the structure to move only in the x direction. Assuming an elastic modulus of 1 GPa and poisson's ratio of 0.3, and that the distributed loads are applied across a thickness of 5 mm, write an FEM code in any programming language you wish to solve this problem (recommend the problem be coded in MATLAB). (10 points) Your code should: (a) use four noded quadrilateral plane-strain elements with the mesh as outlined below, (b) read in the nodal coordinates and element connectivity, (c) formulate the shape functions, stiffness matrix, and residual force vector accounting for local- global transformation and invoking gauss quadrature for the integration, (d) solve for the nodal displacements, (e) find the forces at the imposed boundary nodes, and (f) compute the sig_11, sig_22 stresses at the four integration points of element A.