A method for evaluating the radial dimension of flaws from normal radiographs of large propellant grains

Composite solid propellant grains are radiographed to detect flaws such as voids, cracks and disbonds. It is necessary to determine the effective radial dimensions of these flaws in the propellant. The radial dimension of a flaw can be evaluated from the optical density variations in the radiography image. In the method presented, all the radiographic parameters affecting the sensitivity are amalgamated as a sensitivity factor which is determined experimentally for a particular radiographic set-up. The paper describes the method developed with respect to the radiography of a propellant grain of one metre diameter a 4 MeV linear accelerator