| Abstract |
|
In dynamics, if for the determination of KID, the measurement of the force is possible, thanks to instrumented impacts, this is not the case for the measurement of COD (crack opening displacement). This measurement is enabled thanks to an optical method, which measures the COD and deflection directly on the specimen. This method is based on the electrical signal variation recording which is generated by photo-sensitive cells. Two laser beams cross the sample by 2 holes, which are drilled on both sides of the crack. During the shock, the sample'strain causes the movment of the spots on the cell. The signal's variation is proportional to the displacement. |