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A polymer viscoelastic behavior is to be modelled using standard solid model where a Maxwell model is connected in parallel with a spring. If the rheological constants are given as: E1 = 1.5 Gpa, Ez = 0.256 Gpa, and nu = 560 Gpa = a. Estimate the creep of the polymer at t = 0 and t = 3600 seconds, if it is kept under a constant stress, o = 20 Mpa for a length of 3600 seconds. b. Att = 3600 seconds, the 20 Mpa stress is unloaded and the material is left to recover the creep strain for additional time t = 1200 seconds. Drive the expression for the recovery strain and evaluate the strain of the material at t = 1000 seconds after the recovery. Hint: During the recovery, the constitutive equation of the model reduces to, ni (E1 + E2) Ė + E4E2x = 0 c. From the above information, the materials experiences creep and recovery for a total time t=4800 seconds. Plot the creep and recovery response of the material for the total time with steps of 20 seconds increments. . Provide detailed steps in evaluating and plotting!