Comparison of residual stress measurement methods in solid oxide fuel cell

We performed in-situ measurement of residual stress in an anodesupported cell using sin2ψ method, cosα method and Raman scattering spectroscopy. Residual stress at room temperature was evaluated by the sin2ψ method, cosα method, and simulation. The stress values were generally consistent among the methods, with YSZ having a compressive stress of around 600 MPa. Residual stress analysis at high temperatures was attempted using Raman scattering spectroscopy which, however, was difficult to be applied above 700 C. Instead, cosα method was successfully utilized for the measurement of residual stress during the temperature rise, reduction, and re-oxidation processes. The stress on the electrolyte observed during reduction and re-oxidation was different from that expected with a simple assumption of layered homogeneous sheets. These results showed that the cosα method is the most suitable method for in-situ measurements to validate simulated stress states.