Investigation of the heat distribution in dry friction systems during fade and recovery using fiber-optic sensing and infrared technology

The design of dry-running friction pairings and systems determines not only their installation space and costs, but also their reliability under critical load conditions, for example in emergencies, in the case of faults, and in the event of misuse. While knowledge of the contact pattern is highly important for the development of clutches and brakes, the contact-related measurement of the temperature of these systems has not yet been solved in a satisfactory manner. Despite its importance, the temperature distribution has only been measured in a few studies. Typically, temperature measurements of complete clutches and brakes are carried out using thermocouples only. In this study, a new innovative test setup is presented. This setup is able to measure the heat distribution of the lining and the steel disk of a brake with high spatial resolution by means of fiber optic sensing technology and thermography. As a novelty, it enables measurement of the heat distribution and allows to correlate it with the fade and recovery behavior. Contrary to the expectations, the contact pattern is heterogeneous in circumferential direction. Possible causes are discussed using simulation results. Along with surface analysis, the new setup contributes to the investigation of the causes of fade and recovery.

Development and Performance Evaluation of Eco-Friendly Crab Shell Powder Based Brake Pads for Automotive Applications

The present study deals with the effective usage of crab shell, which is a solid waste in the seafood industry. The crab shell was powdered and treated with chemicals to obtain the chemically treated crab shell powder. The crab shell was powdered and heated to the desired conditions to obtain thermally processed crab shell powder. These two powders so obtained were used with other ingredients in the development of brake pads. For comparison crab shell powder free brake pads were also developed. The developed brake pads were tested for various characteristics as per the industrial standards. Thermal stability was found using Thermogravimetric analysis. The fade and recovery behaviours were estimated for the developed brake pads using Chase test following IS2742 Part-4. The test results indicate that the thermally processed crab shell powder based brake pads showed better thermal stability with a char residue of 37%, while the chemically treated crab shell powder based brake pads had better fade and recovery characteristics with a fade rate of 1.71 % and recovery rate of 99.86 % due to its better heat dissipation and coarse structure. Scanning electron microscopy paved the way to study the worn characteristics of the Chase tested samples. An extensive evaluation method was used to rank the developed brake pads based on the Chase test performance; it also ranked chemically treated crab shell powder-based brake pads as the best performer.

Manufacturing Brake Pads by Using Hot Powder Preform Forging for Low Duty Applications

To develop a high density brake pad for low duty application, a P/M route based on ‘Hot Powder Preform Forging’ was developed, which is not possible by sintering route. The mechanical properties of these materials were characterized using ASTM standards. The limitations of the conventional technique i.e. Compacting and Sintering for the manufacture of brake pads were tried to remove by adopting this technology. It offers better opportunity for pore free materials with better bonding between metallic and non-metallic constituents. Fade and Recovery test were done by using a Krauss Tester. μfade, μrecoveryand μperformancelie within the range of friction materials used for low duty applications.