It depends on type of reinforcement (short fiber, long fiber, fiber mat) but usually a large area of sample is required. Suitable options include, Rockwell B or Brinell
There are several methods to test the hardness of carbon fiber reinforced plastic (CFRP), and the best method depends on the specific application and requirements. Here are some of the most common methods:
1- Rockwell hardness test
2- Brinell hardness test
3- Vickers hardness test
4- Knoop hardness test
5- Shore hardness test
The choice of a specific method depends on the purpose of the test, the equipment available and the required accuracy of the results. It is also important to follow the appropriate testing standards and consult a material testing professional to obtain the best results.