tdehaeze/nass-micro-station-measurements
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Add estimation of mass and stiffness

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Thomas Dehaeze 2020-11-03 09:34:55 +01:00
parent 5f59f13f9a
commit 5089f5b2ab
2 changed files with 28 additions and 9 deletions
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@ -262,7 +262,7 @@ From hammer blows to pure forces / torques:
hold off;
set(gca, 'XScale', 'log'); set(gca, 'YScale', 'log');
ylabel('Magnitude [rad/Nm]'); set(gca, 'XTickLabel',[]);
ylim([1e-9, 2e-6]);
ylim([1e-7, 2e-4]);
ax2 = subplot(2,1,2);
hold on;
@ -289,14 +289,33 @@ From hammer blows to pure forces / torques:
#+RESULTS:
[[file:figs/compliance_diagonal_rotations.png]]
| | Stiffness | Unit |
|-----------+-----------+----------|
| $K_x$ | 1e7 | [N/m] |
| $K_y$ | 1e7 | [N/m] |
| $K_z$ | 2e8 | [N/m] |
| $K_{R_x}$ | ? | [Nm/rad] |
| $K_{R_y}$ | 1.8e7 | [Nm/rad] |
| $K_{R_z}$ | 1e7 | [Nm/rad] |
** Equivalent Stiffness and Mass Estimation
#+begin_src matlab
K = [1e7, 1e7, 2e8, 5e7, 3e7, 2e7];
f_res = [125, 135, 390, 335, 335, 160];
#+end_src
#+begin_src matlab
M = [20, 20, 20, 11, 7, 20];
f_res_est = sqrt(K./M)./(2*pi);
#+end_src
Here is the inertia / stiffness to the granite that can represent the micro-station compliance dynamics:
#+begin_src matlab :exports results :results value table replace :tangle no :post addhdr(*this*)
data2orgtable([K'], {'x', 'y', 'z', 'Rx', 'Ry', 'Rz'}, {'Stiffness', 'Inertia'}, ' %.1g ');
#+end_src
#+RESULTS:
| Stiffness | Inertia |
|-----------+-------------|
| x | 10000000.0 |
| y | 10000000.0 |
| z | 200000000.0 |
| Rx | 50000000.0 |
| Ry | 30000000.0 |
| Rz | 20000000.0 |
** Compare with Model
#+begin_src matlab