Lightweight friction brakes for a road vehicle with regenerative braking. Design analysis and experimental investigation of the potential for mass reduction of friction brakes on a passenger car with regenerative braking.
View/ Open
Thesis Shamsul SARIP after VIVA 01122011 _FINAL.pdf (4.218Mb)
Download
Publication date
2012-11-02Author
Sarip, S. BinSupervisor
Day, Andrew J.Olley, Peter
Qi, Hong Sheng
Keyword
BrakesFriction
Regenerative braking
Automotive
Modelling
Thermal
Finite element analysis
Lightweight
Hybrid electric drive
Rights
The University of Bradford theses are licenced under a Creative Commons Licence.
Institution
University of BradfordDepartment
School of Engineering, Design and TechnologyAwarded
2011
Metadata
Show full item recordAbstract
One of the benefits of electric vehicles (EVs) and hybrid vehicles (HVs) is their potential to recuperate braking energy. Regenerative braking (RB) will minimize duty levels on the brakes, giving advantages including extended brake rotor and friction material life and, more significantly, reduced brake mass and minimised brake pad wear. In this thesis, a mathematical analysis (MATLAB) has been used to analyse the accessibility of regenerative braking energy during a single-stop braking event. The results have indicated that a friction brake could be downsized while maintaining the same functional requirements of the vehicle braking in the standard brakes, including thermomechanical performance (heat transfer coefficient estimation, temperature distribution, cooling and stress deformation). This would allow lighter brakes to be designed and fitted with confidence in a normal passenger car alongside a hybrid electric drive. An approach has been established and a lightweight brake disc design analysed FEA and experimentally verified is presented in this research. Thermal performance was a key factor which was studied using the 3D model in FEA simulations. Ultimately, a design approach for lightweight brake discs suitable for use in any car-sized hybrid vehicle has been developed and tested. The results from experiments on a prototype lightweight brake disc were shown to illustrate the effects of RBS/friction combination in terms of weight reduction. The design requirement, including reducing the thickness, would affect the temperature distribution and increase stress at the critical area. Based on the relationship obtained between rotor weight, thickness and each performance requirement, criteria have been established for designing lightweight brake discs in a vehicle with regenerative braking.Type
ThesisQualification name
PhDCollections
Related items
Showing items related by title, author, creator and subject.
-
The Influence of Braking System Component Design Parameters on Pedal Force and Displacement Characteristics. Simulation of a passenger car brake system, focusing on the prediction of brake pedal force and displacement based on the system components and their design characteristics.Day, Andrew J.; Hussain, Khalid; Ho, Hon Ping (University of BradfordSchool of Engineering, Design and Technology, 2015-10-23)This thesis presents an investigation of braking system characteristics, brake system performance and brake system component design parameters that influence brake pedal force / displacement characteristics as ‘felt’ by the driver in a passenger car. It includes detailed studies of individual brake system component design parameters, operation, and the linear and nonlinear characteristics of internal components through experimental study and simulation modelling. The prediction of brake pedal ‘feel’ in brake system simulation has been achieved using the simulation modelling package AMESim. Each individual brake system component was modelled individually before combining them into the whole brake system in order to identify the parameters and the internal components characteristics that influence the brake pedal ‘feel’. The simulation predictions were validated by experimentally measured data and demonstrated the accuracy of simulation modelling. Axisymmetric Finite Element Analysis (using the ABAQUS software) was used to predict the behaviour of nonlinear elastomeric internal components such as the piston seal and the booster reaction disc which was then included in the AMESim simulation model. The seal model FEA highlighted the effects of master cylinder and caliper seal deformation on the brake pedal ‘feel’. The characteristics of the brake booster reaction disc were predicted by the FEA and AMESim simulation modelling and these results highlighted the importance of the nonlinear material characteristics, and their potential contribution to brake pedal ‘feel’ improvement. A full brake system simulation model was designed, prepared, and used to predict brake system performance and to design a system with better brake pedal ‘feel’. Each of the brake system component design parameters was validated to ensure that the braking system performance was accurately predicted. The critical parameter of brake booster air valve spring stiffness was identified to improve the brake ‘pedal ‘feel’. This research has contributed to the advancement of automotive engineering by providing a method for brake system engineers to design a braking system with improved pedal ‘feel’. The simulation model can be used in the future to provide an accurate prediction of brake system performance at the design stage thereby saving time and cost.
-
FE analysis of the effect of real brake contact areas on brake surface temperaturesZhao, Y.; Qi, Hong Sheng; Day, Andrew J. (2009-01-26)
-
Experimental investigations and finite element analyses of interface heat partition in a friction brake system. New modelling paradigm for describing friction brake systems to support studies of interface temperature, contact pressure, heat flux distribution and heat partition ratio by experiment and FE simulationQi, Hong Sheng; Wood, Alastair S.; Qui, Le (University of BradfordFaculty of Engineering and Informatics, 2018)Operating temperature range is one of the primary design considerations for developing effective disc brake system performance. Very high braking temperatures can introduce effects detrimental to performance such as brake fade, premature wear, brake fluid vaporization, bearing failure, thermal cracks, and thermally-excited vibration [2]. This project is concerned with investigating deficiencies and proposing improvements in brake system Finite Element (FE) models in order to provide high quality descriptions of thermal behaviour during braking events. The work focuses on brake disc/pad models and the degree of rotational freedom allowed for the pad. Conventional models [10] allow no motion/or free motion of the pad. The present work investigates the effect on disc/pad interface temperature and pressure distributions of limited relaxations of this rotational restriction. Models are proposed, developed and validated that facilitate different rotational degrees of freedom (DoF) of the pad. An important influencing factor in friction brake performance is the development of an interface tribo-layer (ITL). It is reasonable to assume that allowing limited rotational motion of the pad will impact the development of the ITL (e.g. due to different friction force distributions) and hence influence temperature. Here the ITL is modelled in the numerical simulations as a function of its thickness distribution and thermal conductivity. Different levels of ITL thermal conductivity are defined in this work and results show that conductivity significantly a1qwffects interface temperature and heat partition ratio. The work is based around a set of test-rig experiments and FE model developments and simulations. For the experimental work, a small-scale test rig is used to investigate the friction induced bending moment effect on the pad/disc temperature. Significant non-uniform wear is observed across the friction surface of the pad, and reasons for the different wear rates are proposed and analyzed together with their effect on surface temperature. Following on from experiment a suite of models is developed in order to evidence the importance of limited pad motion and ITL behaviours. A 2D coupled temperature-displacement FE model is used to quantify the influence of different pad rotational degrees of freedom and so provide evidence for proposing realistic pad boundary settings for 3D models. Normal and high interface thermal conductance is used in 2D models and results show that the ITL thermal conductivity is an important factor influencing the maximum temperature of contact surfaces and therefore brake performance. The interface heat partition ratio is calculated by using the heat flux results and it is confirmed that this value is neither constant nor uniform across the interface surfaces. Key conclusions from the work are (i) that ITL thermal conductivity is an important factor influencing the interface temperature/heat flux distribution and their maximum values, (ii) that allowed motion of the pad significantly affects the interface pressure distribution and subsequently the temperature distribution, (iii) that the transient heat partition in friction braking is clearly quite different to the conventional friction-pair steady heat partition (the heat partition ratio is not uniformly distributed along the interface) and (iv) that the thickness of the ITL increases through braking events, reducing the heat transfer to the disc, and so providing a possible explanation for increasing pad temperature observed over the life time of a brake pad.