## 3 Materials and Methodology
### Load Generation  
The gondola should be mounted in a strength cage using a system of C-beams and articulated joints ensuring the appropriate number of degrees of freedom. The gondola is suspended from the upper beam of the main endurance cage. The diagram of the gondola assembly system is shown in Figure 5. The basis for the assembly of the upper gondola are sets of C140 beams. In the case of the gondola loading system, C100, C120 and C140 beams were used in the configurations presented in Figures 5 and 6. All beams are made of S235 steel. Bolts in screw connections are made of 42 CRMo4 +QT steel (data 40 HM+QT), on which a fine thread M24x2 is made. Figure 5: Geometric model of the gondola with the most important assembly elements marked (screw connections omitted). The designed assembly system leaves an appropriate number of degrees of freedom (all rotations are allowed in several points while blocking the displacement of the upper part of the gondola and allowing the displacement of the rest of the gondola as a result of the axial load). This is done through the following movable connections (\(OX\)--displacement in the direction of the \(X\) axis, \(OY\)--displacement in the direction of the \(Y\) axis, \(OZ\)--displacement in the direction of the \(Z\) axis, \(rotX\)--rotation around the \(X\) axis, \(rotY\)--rotation around the \(Y\) axis, \(rotZ\)--rotation around the \(Z\) axis (definition of the axis in Figures 6a and 3a):  
* ball joint in the bolt connection between the upper beam and the M36x2 bolt--locked: \(OX\), \(OY\), \(OZ\); free: \(rotX\), \(rotY\), \(rotZ\);
* ball joint in the pin connection between the M36x2 bolt and the C-beam system--locked: \(OX\), \(OY\), \(OZ\); free: \(rotX\), \(rotY\), \(rotZ\);
* ball joint in the pin connection between the system of C-beams and the cylinder--locked: \(OX\), \(OY\), \(OZ\); free: \(rotX\), \(rotY\), \(rotZ\);
* simple bolt connection--locked: \(OX\), \(OY\), \(OZ\), \(rotX\), \(rotZ\); casual: \(rotY\). The methodology of loading cableway gondolas is based on the dynamic generation of tensile force. In the discussed case, where the tests will be performed in the hanging position of the gondola, this corresponds to a vertical change in the direction of the force. The transducer generating the force will be a double-acting pneumatic cylinder controlled by a 5/2 valve and quick-release valves. The method is commonly used in force systems, due to the speed of reaction and independence of the generated force from the occurring deformation of the structure. In the case of stepper and mechanical actuators, it is necessary to establish the stroke, which can change with the potential permanent deformation of the structure. In the presented  
Figure 6: Mounted gondola with marked coordinate system (**a**) and the view of the mounted pneumatic cylinder connected by an articulated connection with the C140 C-beam system for loading (**b**). case, i.e., pressure control, the forcing force will be repeatable due to the direct relationship between the generated pressure in the actuator and the force (the force is the product of the piston rod area and the pressure in the pneumatic system), i.e., the force in this solution depends from the amount of pressure. The pressure value signal supplied to the system in the DasyLab environment is converted into the actual value of the force with the simultaneous recording of its value in a continuous mode on the disk of the controlling computer. A pneumatic cylinder CQ 200 \(\times\) 50 mm by Airworks (presented in Figure 6), compliant with the ISO15552 standard, was selected to generate loads as part of the fatigue tests of the cableway gondola. According to the manufacturer's data [31], it can work at a working pressure of up to 10 bar, and at a pressure of 7 bar, it achieves a force of 2199 kg. Due to the fact that the relationship between the force and working pressure is linear, it was determined that the assumed load of 2140 kg (\(2\cdot(G+Q)\)) is obtained at a pressure of about 6.8 bar.