ON THE USE OF OPTO-ELECTRONIC COMPONENTS FOR THE REGISTRATION OF CRACK TIP BEHAVIOUR UNDER DYNAMICAL LOADING CONDITIONS K. Kussmaul, C. Zimmermann, T. Demler et D. Kraemer J. Phys. Colloques, 46 C5 (1985) C5-219-C5-225 DOI: 10.1051/jphyscol:1985528