2. The surface strains at a point on a reactor pressure vessel are to be determined using electrical resistance strain gauges. The principal strain directions at the point are known, but it is not convenient to attach strain gauges in these directions. However, it is possible to attach gauges at 30 and 60 anticlockwise from the direction of the major principal strain , as shown in Figure Q2. The readings from these two gauges, which are not temperature compensated, are o=600u for the gauge along 30 direction and ao= 350u for the gauge along 60 from the major principal strain direction (i) Determine the magnitude of the two in-plane principal strains and Ez [9 marks] (i) Determine the magnitude of the maximum in-plane shear stress where the strain gauges are located, if the reactor has a Young's modulus of E- 220 GPa and Poisson's ratio v 0.34 (4 marks] (i) For safety reasons, the data logger that provides the excitation voltage for the strain gauges is located about 30 m away from the reactor, with two-wire copper leads connecting the strain gauges to the data logger, In your own wonfs, comment, briefly, on the implications of the experimental set-up for the accuracy of the measured strains, identifying any possible sources of error in the strain measurement (7 marks) 30 30 Figure Q2 (Question 21