Question 4 Figure Q4 shows a three-node triangular element for plane stress problems. Assume displacements vary linearly within the element. Node 1 and Node 3 are fixed in the x direction; Node 2 is fixed in the y direction. The other prescribed displacements are: v₁ = 0.05mm V₁ = 0.05mm 12 = 0.025mm where u; and v; are the horizontal and vertical displacements of the ith node (i = 1, 2, 3) of the element, respectively. (a) Find the horizontal displacement (u) and the vertical displacement (v) of Point P(10,10) within the element; (8 marks) (b) Establish the stiffness matrix for this triangular element; and (7 marks) (c) Determine the stresses at Point P(10,10). Elastic modulus E 210 GPa, Poisson's ratio = 0.25, and thickness = 20 mm 3(0,20) y 0.05 P(10,10) 1 0.05 1 (0,0) 2(40,0) Before deformation After de formation Figure Q4 (5 marks) 0.025