Tech Briefs

Thermo-Mechanical Coupled Analysis of an Automotive Disk Brake

In this example, we present a 3D transient dynamic analysis of an automotive disk brake. The model has frictional contact, large displacements and strong thermo-mechanical coupling. The sources of thermo-mechanical coupling are the conductive heat transfer between the rotor and pads which only occurs when there is contact, the heat generation due to friction, and the stresses caused by the non-uniform thermal expansion.

The brake geometry is shown in Figure 1 below. Note that a simplified model of the brake disk/rotor is used in this simulation where holes and slots are ignored.

Figure 1  Schematic of Brake

Unlike in most brake analyses, the rotor deceleration was not prescribed in this model. Instead, the rotor was given an initial angular velocity corresponding to a vehicle speed around 200 km/h, and was augmented with a concentrated mass at its center to account for the vehicle's inertia. A strong braking force was then applied to the brake pads and the rotor deceleration was predicted from the numerical simulation.

The temperature distribution throughout the simulation is shown in the animation above. Note that a non-uniform time scale was used in the animation. Initially, very small steps were taken due to the large angular velocity of the disk. The time steps gradually increased as the disk slowed down. Finally, much larger time steps were taken once the rotor stopped rotating (around t = 4.75 s) to simulate the final brake cooling.

This solution illustrates one of the many complex industrial problems involving frictional contact and thermo-mechanical coupling that can be solved using ADINA.

Disk brake, thermo-mechanical coupling, thermal structural coupling, friction, contact, brake simulation, transient dynamic analysis.