scope:

This test method establishes a procedure for characterizing the toughness of the resin system materials used in making laminates for the fabrication of printed wiring boards. The single-edge-notch bending (SENB) geometry is used to determine the critical-stress-intensity factor, K_1c, and the energy per unit area of crack surface or critical strain energy release rate, G_1c, at fracture initiation. This method assumes linear elastic behavior of the cracked specimen, so there are corresponding restrictions on the linearity of the load-displacement diagram. Use of this test method for printed wiring board laminate materials or other composites may not yield comparative results.