Dr. Jinghan Tang, Jaguar Land Rover, UNITED KINGDOM

Mr. Jibran Bamber, Jaguar Land Rover, UNITED KINGDOM

Due to the large warranty costs incurred, brake squeal and judder are two of the major brake Noise Vibration and Harshness (NVH) issues facing the automotive industry. Brake disc design is one of the main countermeasures for dealing with both problems. Balancing the disc design requirements for squeal and judder is a big challenge. Besides the widely used frequency shifted disc designs, mode split brake discs are an effective alternative for squeal suppression through the disruption of the discs standing wave. However, due to the geometric irregularity caused by the mode split disc pillar distribution, brake thermal judder can be introduced. In this paper, a brake disc design optimisation study was performed utilising multiple Computer Aided Engineering (CAE) methods, dynamometer and vehicle testing in order to produce a mode split disc that reduces both the squeal and thermal judder propensity.

Target squeal frequencies are identified using a Finite Element (FE) model that has been correlated with test results. Complex Eigenvalue Analysis (CEA) was performed to redesign several brake disc’s to split the complex modes contributing to the squeal frequencies. The likelihood of thermal judder for the redesigned brake discs was assessed by a FE Thermal Stability Analysis (TSA) and a full vehicle Multi-Body Simulation (MBS) transfer path analysis. In addition, the structural integrity of the discs were evaluated using FE thermal stress analysis. The disc designs were then verified through a combination of dynamometer and vehicle testing.

The brake disc pillars were shown to be an effective design parameter in the geometrical optimisation study. The pillar distribution, stiffness and mass were identified as contributors to the modal frequency, structural integrity and thermal stability of the discs. Thus, by using multiple virtual methods in conjunction with testing, a mode split brake disc can be designed to meet both squeal and thermal judder requirements.