8577
This study presents development of a test method for characterization of interlayer , mode-I fracture toughness of fused filament fabrication ( FFF ) materials using a modified double cantilever beam ( DCB ) test .
 fracture, fused filament fabrication, FFF, materials, cantilever beam
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 fracture, fused filament fabrication, FFF, materials, cantilever beam