# Table 2 Adopted random generation rules for the parameters $$\varvec{\eta }^{1sh}_l$$ and $$\varvec{\eta }^{1ax}_l$$ tuning the frequency and the magnitude of the applied sinusoidal load components in the x (a) and z (b) directions respectively
$$f^{sh}$$ Hz $$\lbrace \texttt {takerand}\left( \left[ 1,2.75,4.5,6.25,8,9.75,11.5,13.25,15\right] \right)$$$$\cdot \left( \texttt {randn}(0,\sqrt{2})\right) \rbrace$$
$$\gamma ^{sh}$$ $$\lbrace \gamma ^{dof}_i \cdot \texttt {randn(0,1)} \rbrace$$ with $$\gamma ^{dof}_i=\gamma ^{dof}(i)$$ and $$\gamma ^{dof}=\left[ 0.13,0.25,0.38,0.50,0.63,0.75,0.88,1.00 \right]$$ and i is the dof label
$$f^{ax}$$ Hz $$\lbrace \texttt {takerand}\left( \left[ 10,27.5,45,62.5,80,97.5,115,132.5,150\right] \right)$$$$\cdot \left( 2\texttt {randn(0,1)}\right) \rbrace$$
$$\gamma ^{ax}$$ $$\lbrace \texttt {randn(0,1)} \rbrace$$
1. Here, we indicate with randn($$0,\sigma$$) the sampling from a Gaussian probability distribution $${\mathcal {N}}\left( 0,\sigma ^2\right)$$, where $$\sigma ^2$$ is its variance, and with takerand$$\left( \left[ {\varvec{v}}\right] \right)$$ the uniform sampling from the discrete set of values $$\left[ {\varvec{v}} \right]$$