2.1.2 Influence of the tightening torque on the static behavior

To assess the influence of the tightening torque on the static behavior of the plates, a series of tests was performed applying the following three torques: 100, 250, and 350 N˜m. In all cases, plates with a moisture content of 1.8% were employed. The influence of the tightening torque on the static behavior of the plates is represented in Figure 3.

As can be appreciated, the curves have the same appearance in the three cases; all the curves show the inflection point that represents the contact point between the plate and the screw. Again, this inflection point occurs for a displacement of 4.4 mm.

On the other hand, the values of the force at the contact point decrease with the tightening torque: 71.4, 79.0, and 80.6 KN for 100, 250, and 350 N˜m, respectively. Since the plates have the same moisture content, the fact that the lower the tightening torque, the easier the contact, can be explained because the plate can slide

Figure 3. Influence of the tightening torque on the static behavior of the plate.

Optimization of Components of Superstructure of High-Speed Rail: The Spanish Experience DOI: http://dx.doi.org/10.5772/intechopen.80013

Figure 4. Influence of fatigue aging on the static performance of the plates.

more easily with respect to the part that transmits the force. Sliding becomes more difficult as this contact force increases (when the tightening torque is higher).
