When using the above-described approaches, it is recommended that a check be made to determine how well the value of n reproduces the stress-strain curve in the approximate range from the proportional limit (defined as 0.02% ys) to . This can be done by constructing the stress-strain curve using Equation 9.8.4.1.2(b), and comparing an original stress-strain curve through the yield strength with the computed curve. In checking an original stress-strain curve with the computed curve, some judgment must be exercised in the vicinity of the proportional limit since the Ramberg-Osgood relationship may not precisely represent original stress-strain curves in this area. Stress deviations greater than about 5 percent between the two curves suggest that the Ramberg-Osgood relation is not applicable.
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