State of the art on challenges for friction material manufacturers - raw materials, regulations, environmental, and NVH aspects

Friction materials have played a crucial role in safe movement of automobiles and in protection of human life. Enormous cost has incurred in validation of new developed brake pad, a critical safety component, as it involves a lot of inhouse testing along with field testing in different terrains. Further, with an unexpected pandemic and wars, creeping raw material price increases which is a major issue even though researchers have tried to develop innovative materials, which can perform multitasks. Moreover, a paradigm shift towards hybrid and electric vehicles required adjustments in design strategies, related to new friction materials for brakes. The regenerative braking mechanism has taken a major role in electric vehicles (EVs). Therefore, the friction pad is rarely used, which leads to rust/corrosion issues. In addition, the exhaust particles now pale in comparison to non-exhaust emissions. It is a newly identified challenge faced by friction industry as the brake pad wear is one of main contributors of non-exhaust emissions. Also, with no engine noise to cover, the silent nature of EVs creates noise and vibration issues in brake pad even more apparent. Hence, this paper has focused critically on challenges for friction material manufacturers in terms of regulations and raw materials followed by environmental issues and shift towards EVs and NVH requirement. Further, it has discussed with some possible suggestions to reduce the same.