Modelling, analysis and experimental verification of air disc brake used in heavy duty vehicles

This paper proposes a reliable mathematical model that can be used for design stage of new air disc brake (ADB) development projects. All three phases of braking mechanism (brake apply, brake release and automatic adjustment) are modelled by Matlab Simulink in consideration of hysteresis and adjuster performance experiments. Firstly, mathematical relations of each friction interfaces of air disc brake components are derived and mathematical equations adapted to the Simulink model. To ensure the accuracy of ADB system model, hysteresis and adjuster performance experiments are conducted on a prototype disc brake mechanism supported by a test fixture. This prototype single piston disc brake mechanism is fitted to wheel size in 17.5″ used in heavy commercial vehicles. The predicted clamping force, mechanical ratio, brake efficiency and adjuster rate results are verified by using experimental data. The maximum deviation in hysteresis results is 3.08%. Besides, the maximum deviation in adjuster performance results is 7.15%. The numerically and experimentally obtained hysteresis and adjuster performance results show good agreement. The proposed model is modified in consideration of mechanism supported by a brake calliper for predicting actual performance of single piston brake mechanism on the brake level. The hysteresis and the adjuster performance analyses are conducted by using modified ADB model to calculate the hysteresis based brake efficiency and the adjuster rate. The brake efficiency of new single piston brake design provides similar efficiency as the twin piston disc brake used in heavy commercial vehicles.

Multi Scale Modelling of Friction Induced Vibrations at the Example of a Disc Brake System

Friction induced vibrations such as brake squealing, or juddering are still challenging topics in product engineering processes. So far, this topic was particularly relevant for the automobile industry because they were the main market for disc brake systems. However, since mobility habits change, disc brake system are more often to be found on bikes or e-scooters. In all of these systems, vibrations are excited in contacts on the micro scale but affect the user comfort and safety on the macro scale. Therefore, the aim of this cross-scale method is to analyze a system on a micro scale and to transfer the excitation mechanisms on a macro scale system. To address both scales, the current work presents a finite element model on the micro scale for the determination of the coefficient of friction, which is transferred to the macro scale and used in a multi-body simulation. Finally, a finite element modal analysis is conducted, which allowed us to evaluate the brake system behavior on base of an excitation.

Optimal Design of Brake Disc Structures for Brake Squeal Suppression

Aiming at the brake squeal problem of automobile disc brakes, an optimization design method of brake disc structure based on the weighted brake squeal tendency coefficient is proposed. This method is based on the brake squeal complex modal finite element model of a certain disc brake. Based on the validity of the model verified by the bench test, the single-sided disc surface height of the brake disc, the height of the radiating rib, the elastic modulus and the disc are selected. The four key structural parameters of the cap height are used as design variables. Taking the weighted braking squeal tendency coefficient proposed in this paper as the optimization target, the response surface method and the central composite test design are combined to construct a weighted braking squeal tendency coefficient response surface model, and use multi-island genetic algorithm to optimize the model. The results show that the optimization design method proposed in this paper can greatly improve the optimization efficiency while effectively reducing the screaming tendency of the disc brake in the full frequency band, so as to achieve the purpose of improving the NVH performance of the disc brake and improving the comfort of the car.

Airflow simulation when braking with a disc brake

With an increase in train motion speed, the issue of improving braking systems becomes more and more important, since braking systems have a direct impact on safety of traffic. At high travel speeds, the friction elements heat up strongly, so heat dissipation from the brake discs is essential. Therefore, an important task is to study the aerodynamics of brake discs. To achieve these goals, experimental measurements on a special test bench, or simulation in specialized software packages can be used. The article discusses methods for studying air flow when braking with a disc brake. The simulation methods, turbulence models and software packages used for simulation are considered. The influence of the internal geometry of the discs on ventilation and heat dissipation is considered. Also, the geometry of the disc is analysed using simulation in the specialized software. Based on the simulation results, a conclusion about the influence of the internal disc geometry on the air flow through it is drawn.

Thermal stress analysis of disc brake using analytical and numerical methods

This article presents study of the thermal stress development in brake disc and the associated life cycle of the disc. The thermal stress analysis of disc brake under the first brake application and the influences of thermal loads on stress development of the disc have been investigated. The temperature distribution was conducted as a function of disc thickness and braking time. The study was done on the disc brake of Sports Utility Vehicle with a model of DD6470C. Partial solution approach was used to solve analytical temperature distribution through the thickness. The model was done using representative areas of the disc exposed to high temperature whose distribution result was obtained as a function of disc thickness and braking time. The solutions of coupled thermal transient fields and stress fields were obtained based on thermal-structural coupled analysis. Based on the model developed for the study, the positions of high and low stress formations were investigated, and it has been observed that thermal stress and temperature gradient show similar behavior through the thickness of disc. Generally, high temperature and stress components were found on the rubbing surfaces of the disc.

Thermal Analysis of a Disc

The disk brakes are special mechanized parts in a vehicle attached with the tires to help reduce the velocity of the vehicle. As the brake pads caused friction with the disc brakes, there is a temperature rise. Due to this there are great chances of disc brake’s failure if temperature rises above some permissible limit. Solidworks and ANSYS are the design and analysis tools which are used to accomplish this project. The disc brake was designed using Solidworks and it was analysed in ANSYS workbench. The main aim of this project is to analyse two-disc brakes manufactured with different materials to compare their properties and select one with most benefits. Keywords: ANSYS, FEA, Disc brake, Thermal analysis, braking system, Radiation.