scholarly journals A pin-on-disc tribometer study of friction at low contact pressures and sliding speeds for a disc brake material combination

2019 ◽  
Vol 4 ◽  
pp. 100051 ◽  
Author(s):  
Jens Wahlström
Keyword(s):  
Disc Brake ◽  
Material Combination ◽  
Pin On Disc ◽  
Contact Pressures

scholarly journals Wear Induced Failure of Automotive Disc Brakes—A Case Study

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4214 ◽  
Author(s):  
Ali Mohammadnejad ◽  
Abbas Bahrami ◽  
Majid Goli ◽  
Hossein Dehbashi Nia ◽  
Peyman Taheri
Keyword(s):  
Wear Mechanisms ◽  
Optical Microscope ◽  
Outer Edge ◽  
Brake Disc ◽  
Disc Brake ◽  
Root Cause ◽  
Disc Brakes ◽  
Pin On Disc ◽  
Radial Cracks ◽  
Worn Surface

This paper investigated a failure in a ventilated disc brake in an automobile. The failed brake disc had been in service for approximately 10 years. The observed failure was in the form of radial cracks that appeared to have initiated at the outer edge of the disc brake. The cracks were rather straight with no branching. Optical microscope, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) were used to study the microstructure of the failed disc. Vickers microhardness test was also used to evaluate the hardness of the samples. Results showed that the root cause of crack formation, in this case, was related to the excessive wear in the brake disc. Different wear mechanisms, namely abrasive and adhesive wear, were recognized in the failed specimen. Moreover, the worn surface in some areas was covered with fine oxide particles. These particles appeared to have a significant contribution toward abrasion. To further understand the wear mechanisms, pin-on-disc experiments were also conducted on the samples. Results of the pin-on-disc experiments were compared and correlated to the results obtained from the failed brake disc.

scholarly journals Effective Thermo-Structural Analysis for Disc Brake System Simulation

2018 ◽  
Vol 68 (2) ◽  
pp. 125-130
Author(s):  
Pavel Kraus ◽  
Juraj Úradníček ◽  
Miloš Musil ◽  
Michal Bachratý
Keyword(s):  
Thermal Effects ◽  
Transient Analysis ◽  
Standard Procedure ◽  
Computing Time ◽  
Element Model ◽  
Brake System ◽  
Disc Brake ◽  
Disk Brake ◽  
Pin On Disc ◽  
Fully Coupled

AbstractThe evaluation of disk brake squeal is nowadays performed using Finite Element Model. In this standard procedure the thermal effects are omitted. The omission is done because of long computing time of fully coupled brake system thermo-structural transient analysis. This paper is presenting an effective uncoupled thermo-structural FEM procedure. This method is applied on a pin-on-disc system and its time effectiveness is compared to standard full coupled transient analysis.

A pin-on-disc tribometer study of disc brake contact pairs with respect to wear and airborne particle emissions

Wear ◽  
2017 ◽  
Vol 384-385 ◽  
pp. 124-130 ◽  
Author(s):  
Jens Wahlström ◽  
Yezhe Lyu ◽  
Vlastimil Matjeka ◽  
Anders Söderberg
Keyword(s):  
Disc Brake ◽  
Airborne Particle ◽  
Particle Emissions ◽  
Pin On Disc

scholarly journals Thermomechanical and Tribological Properties of SiC/Gr Reinforced Hybrid Aluminum Composite for Disc Brake Application

2021 ◽  
Vol 16 ◽  
pp. 179-186
Author(s):  
Dwi Rahmalina ◽  
Hendri Sukma ◽  
Amin Suhadi
Keyword(s):  
Environmental Factor ◽  
Disc Brake ◽  
Aluminium Matrix Composite ◽  
Aluminum Composite ◽  
Temperature Changes ◽  
Thermomechanical Characteristics ◽  
Average Temperature ◽  
Brake Application ◽  
Pin On Disc ◽  
Braking Distance

The disc brake motorcycle material has been developed by using aluminium matrix composite (AMC) reinforced with matrix particulate ceramic. The composite has many advantages: lightweight, high re-sistance to wear, and controllable strength by adjusting the reinforcement materials percentage. The main issue is the environmental factor that influences the surface properties of the disc. The research aims to study thermomechanical and tribology characteristics to determine the effect of the environmental factor on the composite's wear-out rate. The disc is made from matrix Al7Si6Mg9Zn composite matrix with 10% SiC and 10% graphite (v/v). The disc is produced by squeeze casting method and heated for 4 hours at 180 °C as artificial aging heat treatment. Thermomechanical characteristics are carried out by observing the temperature changes when a load is introduced to the disc. The pin-on-disc method is applied at three different speeds (60, 80, and 100 rpm) under the wet and dry surface on the disc for observing the tribo-logical properties. Thermomechanical characteristics of the disc are average braking time is 3.72 seconds, where the average braking distance is 515.8 cm at speed 40 km/hour with the average temperature of 46.12 °C. The wear-out rate results are steady, where the highest wear out rate for the dry surface is 0.725 mm3/N.m and 6.133 mm3/N.m for the wet surface at 100 rpm.

The use of charging effects in Al/Al2O3 metal matrix composite materials as contrast mechanism in the SEM

1990 ◽  
Vol 48 (4) ◽  
pp. 422-423
Author(s):  
Andreas M. Borchert
Keyword(s):  
Secondary Electron ◽  
Aluminum Matrix ◽  
Interfacial Structure ◽  
Resolving Power ◽  
Coated Sample ◽  
Material Combination ◽  
Uncoated Sample ◽  
Backscattered Electrons ◽  
Contrast Mechanism ◽  
Good Contrast

In Al/Al2O3 MMC's the metal/ceramic interfacial structure is of great concern because aluminum does not wet (i.e. bond) well to alumina. One proposed method to overcome this problem is to form a magnesium-rich spinel (MgAl2O4) as an additional phase between the aluminum matrix and the alumina particle. The spinel forms by diffusion of Mg from the matrix and improves the bonding. Typically the SEM would be the most suitable instrument to study the spinel, but this particular material combination (alumina/spinel) does not have sufficient secondary or backscattered electron contrast to allow for normal imaging. The purpose of this work was to develop a technique for examining the growth and morphology of this spinel at the Al/Al2O3 interface. Samples of an Al/Al2O3 MMC with a spinel at the particle interface were prepared according to standard metallographic procedures. Certain samples were sputter coated with a gold film of approximately 12 nm thickness; other samples were examined uncoated. Nonconductive, uncoated specimens charge under the incident electron beam if the accelerating voltage is below E1 or above E2 in Figure 1. In both of cases (below E1 and above E2) the number of electrons entering the sample is higher than the number of electrons leaving the sample. The resolving power of the SEM is usually degraded by this effect and therefore nonconductive specimens are coated with a layer of conductive material prior to observation. Figure 2 shows how this effect can create contrast between two materials due to its effect on the secondary electron detector bias voltage. Figure 3 shows that this contrast mechanism exists for the material combination alumina/spinel. The secondary electron image of a coated sample (3a) shows almost no contrast between alumina and spinel whereas the uncoated sample (3b) shows good contrast due to the different charging characteristics of the materials. The alumina charges stronger than the spinel and appears brighter in the image. The assumption that the effect is due to secondary electrons is supported by Figure 4. The micrograph in Figure 4a was obtained by backscattered electrons only and shows poor contrast whereas the micrograph in Figure 4b was obtained by secondary and backscattered electrons and shows good contrast. Figure 5 shows micrographs obtained at different operating voltages. The reduction in contrast at lower operating voltages is due to reduced charging.

Maximum Interlabial Pressures in Normal Speakers

1997 ◽  
Vol 40 (2) ◽  
pp. 400-404 ◽  
Author(s):  
Virginia A. Hinton ◽  
Winston M. C. Arokiasamy
Keyword(s):  
Speech Production ◽  
Contact Pressure ◽  
Direct Evidence ◽  
Unit Area ◽  
Jaw Movement ◽  
Contractile Forces ◽  
Contact Pressures ◽  
Muscle Contractile

It has been hypothesized that typical speech movements do not involve large muscular forces and that normal speakers use less than 20% of the maximum orofacial muscle contractile forces that are available (e.g., Amerman, 1993; Barlow & Abbs, 1984; Barlow & Netsell, 1986; DePaul & Brooks, 1993). However, no direct evidence for this hypothesis has been provided. This study investigated the percentage of maximum interlabial contact pressures (force per unit area) typically used during speech production. The primary conclusion of this study is that normal speakers typically use less than 20% of the available interlabial contact pressure, whether or not the jaw contributes to bilabial closure. Production of the phone [p] at conversational rate and intensity generated an average of 10.56% of maximum available interlabial pressure (MILP) when jaw movement was not restricted and 14.62% when jaw movement was eliminated.

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