New Release of the SAE J3080 for Rotor Crack Test of Air Disc Brakes

Last month, SAE International published a new recommended practice for rotors fitted with air disc brake systems. The SAE J3080_201803 provides a laboratory test method for thermal cracks induced by repeating 500 brake drag applications to mimic mountain descent at a constant speed of 85 km/h (~52 mph). Cracks on the brake disc can compromise the structural integrity of the foundation brake. These failures can lead to significant brake maintenance and vehicle downtime, disrupting the fleet efficiency and on-time delivery. In order to provide an early assessment of this failure mode, the SAE Foundation Brake Committee for Commercial Vehicles, initiated in 2015 a joint effort with European participation. The task force included vehicle manufacturers as well as brake suppliers.

In order to accommodate different approaches to brake conditioning (burnishing or bedding), the SAE J3080_201803 incorporates two methods: Method A uses brake applications at 200 °C and 300 °C, in addition to performance sections of torque output versus pressure during the bedding; Method B uses a single bedding cycle at 150 °C. Both test methods harmonize test conditions for common brake sizes and axle ratings, control limits for test execution, and inspection criteria for cracks and test termination.

Link Engineering Company played a large role in the development process as well as in supporting and driving this creation. LINK is motivated to continue their support to better improve brake systems and is excited to see the impact that the new SAE J3080 will have on the industry.

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