| 1. |
- Riva, Gabriele, et al.
(författare)
-
A Multi-Scale Simulation Approach to Investigate Local Contact Temperatures for Commercial Cu-Full and Cu-Free Brake Pads
- 2019
-
Ingår i: Lubricants. - Basel : MDPI. - 2075-4442. ; 7:9
-
Tidskriftsartikel (refereegranskat)abstract
- Copper from vehicles disc brakes is one main contributor of the total copper found in the environment. Therefore, the U.S. Environmental Protection Agency (EPA) and the automotive industries started the Copper-Free Brake Initiative. The pad friction material is essentially composed of a binder, fillers, reinforcing fibres and frictional additives. Copper and brass fibres are the most commonly used fibres in brake pads. There is a need to understand how the contact temperature distribution will change if copper-based fibres are changed to steel fibres. The aim of this work is, therefore, to investigate how this change could influence the local contact temperatures. This is done by developing a multi-scale simulation approach which combines cellular automaton, finite element analysis (FEA) and computational fluid dynamics (CFD) approaches with outputs from inertia brake dyno bench tests of Cu-full and Cu-free pads. FEA and thermal-CFD are used to set the pressure and the temperature boundary conditions of the cellular automaton. The outputs of dyno tests are used to calibrate FEA and CFD simulations. The results of the study show lower peaks in contact temperature and a more uniform temperature distribution for the Cu-free pad friction material.
|
|
| 2. |
- Riva, Gabriele, 1988-, et al.
(författare)
-
An FEA approach to simulate disc brake wear and airborne particle emissions
- 2019
-
Ingår i: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 138, s. 90-98
-
Tidskriftsartikel (refereegranskat)abstract
- Emissions from disc brake wear adversely affect the air quality in cities. Finite Element Analysis (FEA) approaches focussing on the macroscopic wear of pads and rotors can be found in the literature, but none of these take the wear and emission dependence of the local contact pressure and sliding speed into account. The aim of the present study is to further develop an FEA approach for simulation of macroscopic wear and airborne emission to include the dependences of local contact pressure and sliding speed by implementing wear and emission maps obtained by pin-on-disc tribometer tests. Results from a dyno bench test are compared with simulated results. The simulated rotor and pads wear, and airborne emissions are in line with the measured values.
|
|
| 3. |
- Riva, Gabriele, et al.
(författare)
-
Simulation of Contact Area and Pressure Dependence of Initial Surface Roughness for Cermet-Coated Discs Used in Disc Brakes
- 2019
-
Ingår i: Tribology in Industry. - : Faculty of Engineering, University of Kragujevac. - 0354-8996 .- 2217-7965.
-
Tidskriftsartikel (refereegranskat)abstract
- Friction, wear, and emission performance strongly depend on the contact pressure and area at the interface of the pad and disc. The contact situation at the pad-to-disc interface can be explained by the formation and destruction of mesoscopic sized contact plateaus on the pad surface. Experimental studies report that the initial surface roughness of cermet-coated discs strongly affects friction, wear and emission performance. This is explained by the formation of secondary plateaus on the disc surface. The aim of this work is to extend an existing cellular automaton approach to include the formation of secondary plateaus on the disc surface in order to explain experimental results reported in the literature. First, to investigate the validity of the novel simulation approach, a cermet-coated cast iron disc is tested against a low-met pad material with a pin-on-disc tribometer. The same conditions are used as input in a simulation. Then, the initial disc roughness influence on contact pressure and area of the same cermet-coated disc is compared with results reported in the literature. The topographies of the measured and simulated disc surfaces are qualitatively in line. An initial rougher disc surface results in a considerably lower contact area than does a smother surface.
|
|
