Accurate simulation of anti-lock braking systems (ABS) requires detailed models of several subsystems in different physical domains. The most important subsystems are the hydraulic brake system, the tire and the control algorithm. The creation of detailed models of each subsystem in a single modeling tool may be difficult if not impossible. To overcome this, co-simulation may be used to combine the strengths of different tools. In this article, co-simulation between Dymola and Abaqus is used to investigate the performance of an ABS algorithm with a highly detailed finite-element tire model. The brake system hydraulics along with the control algorithm are simulated in Dymola while the tire model, the wheel, the braking caliper and the contact with the road are simulated in Abaqus. While computationally more expensive than a traditional modeling approach when a semi-analytical tire model (such as the Magic Formula model) may be used to model the tire and tire road interaction, the approach described in this paper includes a fair amount of details when modeling of the tread, the tire plies, the wire reinforcements in the tire and the contact with the road. The necessary data is exchanged between the two applications using the co-simulation capabilities available in Abaqus and the .DLL option in Dymola. Sensors in Abaqus provide information about the mechanical state of the system such as forward translational velocity, angular velocity/acceleration and the free rolling effective radius. This information is communicated to Dymola at frequent simulation time intervals at runtime. Dymola uses this information as inputs and computes the brake caliper clamp force. This force is communicated in turn to Abaqus which determines the force on the brake rotor.

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Generating structured hexahedral finite element meshes on tread patterns is a challenging and laborious task due to the complex pattern geometry. However, creating good quality tetrahedral meshes on these geometries is relatively straightforward and can be fully automated. Despite the convenience and time saving, analysts have long avoided tetrahedral elements because of inadequate contact stress accuracy, which is critical for pattern wear prediction. Recent advances in contact formulation has vastly improved the accuracy of contact stresses predicted by tetrahedral meshes. This article presents a comparative study between the results predicted by tetrahedral and hexahedral meshes under slow rolling conditions. Comparisons are presented for footprint solution quantities such as contact stresses as well as global solution quantities such as residual aligning torque.