DISCUSSION ON RESEARCH ACTIVITY PUBLISHED AS “FULL-SCALE DYNAMIC VIBRATION TEST AND DYNAMIC MODEL OF INERTIAL MASS DAMPER”: Koich SUGIMOTO, Akira FUKUKITA, Tetsuya HANZAWA and Masanari OKAMOTO, J. Struct. Constr. Eng., AIJ, Vol. 83, No. 749, 997-1007, July, 2018

This paper was interesting; however, lack of description prevented me from correct understanding of it. I also thought that the authors could not recognize strictly what the specimen and the test equipment are, respectively. This leads to an inappropriate testing and verification of analytical modeling. The damping characteristics due to the grease filled in the nut are interesting.