This master's thesis deals with the influence of axisymmetric prestressing of a thin disc on its stress-strain properties. Each disc has a certain rotational speed at which it loses stability and starts to oscillate laterally, which is not desirable, especially in the circular saw industry. The aim of prestressing is to increase the stiffness of the disc, which in turn increases its natural frequencies and critical rotational speeds. Therefore, we wanted to find out whether the finite element method can be used to successfully simulate the process of prestressing. To validate the results, we selected a commercially available prestressed disc and measured its transverse stiffness and groove profile. We found that the simulation results of two differently simplified models agree well with the experimental measurements. The influence of the prestress force and the rolling radius on the stiffness and natural frequencies of the disc was analysed. We found that a commercially available disc was prestressed with a rolling force of 8.9 kN and rolled at an optimum radius of 100 mm. The critical modal shape of the disc was a shape with two nodal diameters, and the associated natural frequency increased by 8.66% after prestressing.
|
