Thermal-mechanical Coupling Analysis And Fatigue Damage Prediction On Continuous Braking Of Heavy Truck Brake

The brakes provide an important guarantee for the security and reliability of thevehicles, it is one of the most important safety components in the car. Drum brakes havebeen widely used in heavy-duty trucks and buses, because of it simple and compactstructure, low cost and good braking performance. Braking process is complex because itinvolves3D(three-dimensional) frictional contact and thermal coupling problem. Thispaper use the finite element simulation technology to analyze transient thermal-structuralcoupling of the whole braking process, and predict the service life of the brake drumwhose surface existed defects.This article select a heavy-duty truck’s drum brakes as the research object, thesimulation heat transfer parameters were calculated according to the heat transfer andtribology theory, and summarized the brake friction heat law. The3D finite element drumbrakes model was created by ABAQUS, and the whole braking process was simulatedusing the direct coupling method. It analyzed the friction plate and brake drum surfacecontact pressure distribution, and obtained the long slope transient temperature field andstress field change rule when the vehicle under different loads and different coolingmodes.By analyzing the brake coupling results, comparing the3D stress of the drum brake’sinner surface, it found that the axial stress and circumferential stress are the main reasonsfor the drum brake’s axial cracking on the inner surface. The friction surface of the drumbrake suffered double impact of moving heat source and convective heat transfer, so thenode temperature was "jagged" cyclical changes. Based on the basic principles of thefatigue crack growth, using Nsoft software to predicted the surface crack defects drumbrake’s service life in the long slope continued braking condition, it provided a referencefor the heavy-duty truck drum brake repairs and its structural improvements.