A Coupling Analysis of Thermal Buckling and Vibration in Disc Brakes 2020-01-1606
Non-uniform high temperature gradient is generated on the surface of brake disc during braking. This temperature gradient induces thermal buckling, a deformation characterized by either a coning mode or potato chip mode. In a rotating machinery vibration occurs with a natural frequency at a certain rotational speed, leading to a change in the contact conditions at the frictional interface. It may cause a redistribution of temperature and thus the thermal buckling modes. Meanwhile some vibration modes in a brake system can also be excited by the deformation modes of thermal buckling in the rotor. The coupled and uncoupled problems of thermal buckling and vibration are analyzed using an ABAQUS benchmark vented brake model. It is known that different assumptions of temperature, either in the radial or axial direction, may lead to different solutions of thermal buckling. In this study, we assumed some representative temperature profiles in the radial direction, including linear, sinusoidal and exponential functions, meanwhile the circumferential distribution of temperature was maintained uniform. The effect of structural vibration on the thermal buckling modes, as well as the effect of buckling modes on vibration in this simplified situation, were both analyzed. Although it is concluded that vibration during braking does not significantly increase the chance of buckling for the ABAQUS benchmark model, the results are highly dependent on the chosen parameters including materials, dimensions, and rotational velocity, and the coupling can be strong in some conditions.
Joseph-shaahu Shaahu, Kingsford Koranteng, Yun-Bo Yi