Ali Belhocine

Simulation of fully coupled thermomechanical analysis of automotive brake discs

The vehicle braking system is considered to be one of the most fundamental safety-critical systems in modern vehicles, as its main purpose is to stop or decelerate the vehicle. The frictional heat generated during braking application can cause numerous negative effects on the brake assembly, such as brake fade, premature wear, thermal cracks and disc thickness variation. In the past, surface roughness and wear at the pad interface have rarely been considered in studies of the thermal analysis of a disc brake assembly using the finite element method. The ventilated pad-disc brake assembly is built by a three-dimensional model with a thermomechanical coupling boundary condition and multi-body model technique. The numerical simulation for the coupled transient thermal field and stress field is carried out sequentially with the thermal-structural coupled method, based on ANSYS software, to evaluate the stress fields of deformations, which are established in the disc with the pressure of the pads and in the conditions of tightening of the disc; thus, the contact pressure distributions field in the pads is obtained, which is another significant aspect in this research. The results obtained by the simulation are satisfactory compared with those of the specialized literature.

Thermal and structural analysis of disc brake assembly during single stop braking event

Abstract An automobile disc brake system is used to perform three basic functions, i.e. to reduce speed of a vehicle, to maintain its speed when travelling downhill and to completely stop the vehicle. During these braking events, the disc brake may suffer from structural and wear issues. It is quite sometimes that the disc brake components fail structurally and/or having severe wear on the pad. Thus, this paper aims to determine disc temperature and to examine stress concentration, structural deformation and contact pressure of brake disc and pads during single braking stop event by employing commercial finite-element software, ANSYS. The paper also highlights the effects of using a fixed calliper, different friction coefficients and different speeds of the disc on the stress concentration, structural deformation and contact pressure of brake disc and pads, respectively. The thermal-structural analysis is then used with coupling to determine the deformation and the Von Mises stress established in the disc, the contact pressure distribution in pads.

Thermomechanical analysis of vehicles gray iron brake discs

Purpose – The main purpose of this study is to analyse the thermomechanical behavior of the dry contact between the brake disc and pads during the braking phase.Design/methodology/approach – The simulation strategy is based on computer code ANSYS11. The modeling of transient temperature in the disc is actually used to identify the factor of geometric design of the disc to install the ventilation system in vehicles. The thermal‐structural analysis is then used coupling to determine the deformation and the Von Mises stress established in the disc, the contact pressure distribution in pads.Findings – The analysis results showed that temperature field and stress field in the process of braking phase were fully coupled.Originality/value – The results are satisfactory when compared with those of the specialized literature.

Thermomechanical Behaviour of Dry Contacts in Disc Brake Rotor with a Grey Cast Iron Composition

The objective of this study is to analyse the thermal behaviour of the full and ventilated brake discs of the vehicles using computing code ANSYS. The modelling of the temperature distribution in the disc brake is used to identify all the factors and the entering parameters concerned at the time of the braking operation such as the type of braking, the geometric design of the disc and the used material. The numerical simulation for the coupled transient thermal field and stress field is carried out by sequentially thermal-structural coupled method based on ANSYS to evaluate the stress and deformations on disc surface including the contact pressure on the pads. The results obtained by the simulation are satisfactory compared with those of the specialized literature.

Thermomechanical Coupling Analysis of a Disc Brake Rotor

The main purpose of this study is to analyze the thermomechanical behavior of the dry contact between the brake disc and pads during the braking phase. The simulation strategy is based on computer code ANSYS11. The modeling of transient temperature in the disc is actually used to identify the factor of geometric design of the disc to install the ventilation system in vehicles. The thermal-structural analysis is then used to determine the deformation established, the von Mises stresses in the disc, and the contact pressure distribution in pads. The results are satisfactorily compared with those found in the literature.

Similarity solution and Runge Kutta method to a thermal boundary layer model at the entrance region of a circular tube: The Lévêque Approximation

In the thermal entrance region, a thermal boundary layer develops and also reaches the circular tube center. The fully developed region is the zone in which the flow is both hydrodynamically and thermally developed. The heat flux will be higher near the inlet because the heat transfer coefficient is highest at the tube inlet where the thickness of the thermal boundary layer is zero and decreases gradually to the fully developed value. In this paper, the assumptions implicit in Leveques approximation are re-examined, and the analytical solution of the problem with additional boundary conditions, for the temperature field and the boundary layer thickness through the long tube is presented. By defining a similarity variable, the governing equations are reduced to a dimensionless equation with an analytic solution in the entrance region. This report gives justification for the similarity variable via scaling analysis, details the process of converting to a similarity form, and presents a similarity solution. The analytical solutions are then checked against numerical solution programming by Fortran code obtained via using Runge-Kutta fourth order (RK4) method. Finally, others important thermal results obtained from this analysis, such as; approximate Nusselt number in the thermal entrance region was discussed in detail.

A numerical parametric study of mechanical behavior of dry contacts slipping on the disc-pads interface

Abstract The aim of this contribution is to present a study based on the determination and the visualization of the structural deformations due to the contact of slipping between the disc and the pads. The results of the calculations of contact described in this work relate to displacements, Von Mises stress on the disc, and contact pressures of the inner and outer pad at various moments of simulation. One precedes then the influence of some parameters on the computation results such as rotation of the disk, the smoothness of the mesh, the material of the brake pads and the friction coefficient enter the disk and the pads, the number of revolutions and the material of the disk, the pads groove.

CFD MODELING AND COMPUTATION OF CONVECTIVE HEAT COEFFICIENT TRANSFER OF AUTOMOTIVE DISC BRAKE ROTORS

The braking network of an automobile is one of its most important control systems. For many years, disc brakes have been used for safe retardation of a vehicle. During braking, an enormous amount of heat is generated, and for effective braking, sufficient heat dissipation is essential. The thermal performance of a disc brake depends on characteristics of the airflow around the brake rotor; hence, aerodynamics is key in the region of brake components. Using ANSYS CFX software, we performed a computational fluid dynamics (CFD) analysis on a brake system to study the behavior of airflow distribution around disc brake components. We were interested in the determination of the heat-transfer coefficient on each surface of a ventilated disc rotor, varying with time in a transient state. Using CFD analysis, we imported surface film condition data into a corresponding finite-element method for disc temperature analysis.

Computational fluid dynamics (CFD) analysis and numerical aerodynamic investigations of automotive disc brake rotor

Abstract Braking system is one of the important control systems of an automotive. For many years, the disc brakes have been used in automobiles for safe retardation of the vehicles. During braking, enormous amount of heat will be generated and for effective braking sufficient heat dissipation is essential. The thermal performance of disc brake depends upon the characteristics of the airflow around the brake rotor and hence the aerodynamics is an important in the region of brake components. A computational fluid dynamics (CFD) analysis is carried out on the braking system as a case study to make out the behaviour of airflow distribution around the disc brake components using ANSYS CFX software. We are interested in the determination of the heat transfer coefficient (HTC) on each surface of a ventilated disc rotor varying with time in a transient state using CFD analysis, and then imported the surface film condition data into a corresponding FEM model for disc temperature analysis.

Stress analysis of automotive ventilated disc brake rotor and pads using finite element method

The complexity of the physical or technological systems to be developed or studied led to employing numerical methods based on the principle of an approach as possible nominal solution, but these require large computations requiring efficient computers. The computer code ANSYS also allows the determination and the visualization of the structural deformations due to the contact of slipping between the disc and the pads. The results of the calculations of contact described in this work relate to displacements, Von Mises stress on the disc, contact pressures of the inner and outer pad at various moments of simulation. One precedes then the influence of some parameters on the computation results such as rotation of the disc, the smoothness of the mesh, the material of the brake pads and the friction coefficient enter the disc and the pads, the number of revolutions and the material of the disc, the pads groove.