GB/T 33835-2017Test method of impact strength for friction material (English PDF)

Foreword

This Standard was drafted as per the rules specified in GB/T 1.1-2009.

1 Scope

This Standard specifies the sample preparation and test methods for the impact strength test of friction material.

This Standard is applicable to the friction material with resin as the binder.

2 Test Conditions

2.1 The test equipment is the simple beam pendulum impact tester; its impact energy is divided into two levels, namely, Level-0.980 7 J and Level-3.922 8 J; the impact velocity is of 2.9m/s.

2.2 The size and interrelationships among pendulum, specimen and supporting seat shall conform to the provisions of Figure 1.

2.3 The consumption value of its own stored energy during the test shall be within 10% ~ 80% full scale of each level.

4 Test Procedures

4.1 Adjust the impact tester fulcrum distance L into 40.0mm±0.2mm.

4.2 Select the appropriate pendulum; the load shall meet the requirements of 2.3.

4.3 Calibrate the zero point on the dial plate of tester; place the pendulum on the pre-lifting hook position.

4.4 Use the Vernier caliper with precision of 0.01mm to measure the specimen width and thickness. Measure 3 points evenly distributed within 10mm range of the specimen middle part; then take the minimum value.

4.5 Place the specimen horizontally on the framework as per the provisions of 3.2; so that the pendulum blade can strike the entire thickness line; and align with the specimen centerline.

4.6 Smoothly release the lock hook; so that the pendulum falls freely; and the specimen is exerted impact load and is broken; read the consumed power from the dial plate. The specimen shall be broken within 10mm range in the middle; otherwise, such test results are rejected.

5 Calculation

The impact strength of specimen shall be calculated as per Formula (1). Where. aK - impact strength of specimen, in J/cm²;

AK - consumed impact energy of specimen, in J; b - specimen width, in cm; d - specimen thickness, in cm.

Take the arithmetic mean of the test results of 5 specimens as the report value; retain 3 digits after the decimal point. […]