An Experimental Investigation of the Displacement Transmissibility for a Two-Stage HSLD Stiffness System

Round 1

Reviewer 1 Report

There are numerous papers in the literature that are concerned with high static low dynamic stiffness systems, some of which treat 2 DOF systems. This paper presents an appropriate critique of some of these, and the authors clearly state the contribution their paper makes to this body of literature. The experimental validation is the more valuable contribution in my opinion and warrants publication.

 Points of clarification

 

 -   The transmissibility ratio of a nonlinear system is unambiguously defined when solved using the harmonic balance method. How is it defined for the Runge-Kutta numerical integration when the time response comprises multiple harmonics? Is the peak amplitude taken in steady state? Or the Fourier series coefficient computed?

 

-        -  Page 9 “frequency sweep”. Did you sweep down as well as up and, if so, did you get the same results?

-        - In figure 8, is the comparison between the 1 and 2 DOF system like-for-like in terms of static deflection of the springs?

-        - The authors note the discrepancy between the measured and numerical/analytical solutions and attribute it to an “unmodeled vibration mode” of the system due to rotational movement. This is entirely possible and very likely. From the data I suspect that there are multiple modes here (e.g. rotation in another orientation?), although it is difficult to say exactly how many.

Some editorial corrections:

 -   Kv1 is undefined. I think it corresponds to k11 in Figure 2. Similarly, is kv2 the same as k12 in the figure?

-       -  Page 1. “high static low dynamic stiffness (HSLD) systems, also called Quasi Zero Stiffness (QZS)”.  QZS is a specific and extreme example of an HSLD stiffness system but the terms are not equivalent. Also, check for occurrences of QZS throughout the paper where you mean HSLD (e.g. in section 5).

 - The term transmission ratio is used extensively, including in the axis labels in the figures. Should these occurrences be replaced with transmissibility?

 

 -        Page 9 line 248 weight should read mass.

-       Conclusions. “better dynamic response then a SDOF or linear system”. Then should read than.

 

 -        Does the journal have a policy on whether there should be a space between the value and the units?

Author Response

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Reviewer 2 Report

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Author Response

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Round 2

Reviewer 2 Report

The Authors have correctly made all the required changes.