## 3 Results
### Full-Field DIC Study
#### 3.4.3 Adjustment and Positioning of the Magnet Under Load  
The final experimental measurements were conducted on the test stand presented in Figure 9a. The test was divided into five stages:  
1. Tightening the clamp bolts with torque \(M_{c}\) = 4 Nm;
2. Tightening the adjustment bolts with torque \(M_{r}\) = 5 Nm;
3. Loading the holder with forces within the range \(F\) = 1.25-2.5 kN;
4. Calibration of the handle by increasing the tension of the adjusting screws using torque in the range \(M_{r}\) = 5-10 Nm;
5. Calibration of the handle by loosening the adjusting screws using torque in the range \(M_{r}\) = 10-0 Nm. The deformation of the holder (without load \(F\)) at the end of stage 1 and 2 is shown in Figure 27a and Figure 27b, respectively. These stages are described in detail in previous Sections 3.4.1 and 3.4.2, and they are not discussed here. In the third stage, DIC analysis was focused on the behavior of the holder subjected to the external load \(F\). The magnetic force (external load) was applied using the weights shown in Figure 9. The images were made under a few loads, \(F\) = 1.25, 1.5, 1.75, 2.0, 2.25, and 2.5 (all in kN). The geometry of the rigid support frame (Figure 9) was set to provide the possibility to apply the external load. The disadvantage of such a support frame is that it is susceptible to a small deformation under load \(F\). Even though these deformations of the support frame were small, they were comparable to the deformation of the magnet handle. Because of this, the results given in Figures 17, 18 and 28a must be assessed, including these support frame deformations. The positions of the characteristic points LC and RC of the magnet under different loads \(F\) are given in Figure 28a. Here are also the provided deformations introduced to the magnet holder from the support (points OFLD and OFRD). Figure 26: Vertical deformation of magnet holder for different adjustment bolt torques \(M_{r}\): (**a**) bolts on left hand-side \(M_{r}\) = 10 Nm, bolts on right hand-side \(M_{r}\) = 0 Nm; (**b**) \(M_{r}\) = 10 Nm on all adjusting bolts. Figure 27: Vertical deformation of magnet holder for the following: (**a**) \(M_{c}\) = 4 Nm, \(M_{r}\) = 0 Nm, \(F\) = 0 kN; (**b**) \(M_{c}\) = 4 Nm, \(M_{r}\) = 5 Nm, \(F\) = 0 kN. The obtained relationships are almost linear. The deformation of the whole magnet holder for two cases with the minimal \(F\) = 1.25 kN and the maximal \(F\) = 2.5 kN external load are presented in Figure 29a and Figure 29b, respectively. Apart from the support deflection, no undesirable behavior of the magnet holder was observed under external load. In the final stages (no. 4 and 5), the adjustment of the magnet position under the external load was studied. First of all, the adjustment bolts were tightened (up to \(M_{r}\) = 10 Nm--see Figure 30) and after that loosened until the adjustment screws are completely unloaded. The displacements of points LC and RC of the magnet for different adjustment torques \(M_{r}\) are shown in Figure 28b. Comparing the curves of both stages 4 and 5, it can be seen that calibration is possible by tightening and loosening the adjustment bolts (exemplary images for tightening and loosening to the same value of \(M_{r}\) = 7 Nm are presented in Figure 31a and Figure 31b, respectively). However, it should be noted that there are some differences between both processes. The largest differences were observed during the initial process of loosening the bolts. In such a case, \(M_{r}\) torque reduction caused smaller changes in the magnet movement than during tightening the adjustment bolts. On the other hand, there was no influence of adjustment torque \(M_{r}\) on the deformation of the support frame (Figure 23). Figure 28: Displacement of “magnet” and deformation of outer frame for the following: (**a**) \(M_{c}\) = 4 Nm, \(M_{r}\) = 5 Nm, \(F\) = var; (**b**) \(M_{c}\) = 4 Nm, \(M_{r}\) = var, \(F\) = 2.5 kN.