Dear Liye,
Matthias Kretschmer was the lead author of this paper and generated all of the results. I do not have access to all of his input files. But the paper mentions the flapwise bending moment, which is “RootMyb1” in ElastoDyn, so, I assume that is correct. The paper also describes the formula used to calculate the DEL and it is the short-term DEL only, without considering the Goodman correction for mean loads and weighting across load case that is necessary for long-term DEL calculation. The values of N_eq (= 600) and the material exponents (4 for the tower, and 10 for the blades) are also stated in the paper.
Best regards,