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Brake squeal of the light vehicle disc brakes have been the subject of numerous studies in the last thirty years. Several analytical and numerical models as well as dynamometer and vehicle test procedures are widely used in the industry. The noise performance of many vehicles have been improved significantly over the last few years. On the other hand, the squeal noise of the heavy-duty vehicle drum brake has not been studied extensively. The noise performance of the heavy-duty drum brake has been lagging behind that of the light vehicle brakes. With the implementation of the revised FMVSS121 stopping distance requirement, higher friction materials are needed, which generally results in even more brake noises due to higher excitation. Public awareness of noise influence on the environment is forcing the heavy-duty vehicle brake industry to deliver better brake noise performance.

A new technique utilizing Nastran CWELD elements to model the shoe-lining interface is proposed for brake pad finite element modeling. The method of constructing the interface model, including the location of each CWELD element, is presented. The proposed interface model is used to investigate the effects of end-lift on pad modal parameters. Applications of the interface model on simplifying brake pad and rotor meshes are also illustrated.

A multi-dimensional constrained optimization method is presented to automatically adjust the elastic parameters of the friction material in order to minimize the discrepancy between finite element modal analysis and experimental modal testing. Application examples on semi-met, low-met and NAO materials show much improved results using the proposed method. Alternative material model that are not possible to use with the current commercially available ultrasonic measurement equipment, such as the orthotropic model, is also investigated.

A simple finite element model is presented as a rapid engineering tool for designing pad shape to reduce high frequency brake squeal. The mechanism, effect, and design methodology of pad shape on squeal are discussed. The proposed model and method are applied on fifteen different brakes to generate the alternative pad shape designs. Validation tests on dynamometer demonstrate very promising results for the proposed tool and method.

An analytical model based on finite element method and a modal coupling approach used for evaluating high frequency disc brake squeal is discussed. The model incorporates the pad-rotor mode locking effect, which is responsible for a good share of high frequency disc brake squeal problems. The application of the model in the optimization of pad shapes for several vehicle platforms are presented with good correlation to vehicle and dynamometer tests.