caa a22 4500 469124180 CHVBK 20180323133146.0 cr unu---uuuuu 170328e19920101xx s 000 0 eng 10.1007/BF00034671 doi (NATIONALLICENCE)springer-10.1007/BF00034671 Subcritical crack propagation under cyclic stress impulse [Elektronische Daten] [A. Gomaa, A. Hamdy, Abdelsamie Moet] An equipment has been designed to observe subcritical crack propagation under cyclic impulse (impact) loads. The equipment design uses the concept of stress wave propagation in bars. A four point bend notched specimen is struck by an incident bar with a known stress wave. The test specimens were machined from PMMA sheet (Lucite®). The crack, initiated from the notch, was detected by a step wise increase of a graphitic grid imprinted on one side of the specimen. The data was analyzed using fracture mechanics theory and compared with that of conventional fatigue. Although the applied strain rate was quite high (≃1s−1), stable crack propagation was significant. It appears that the elastic energy stored in the specimen within the duration of each impulse is dissipated in craze formation at the tip of the advancing crack. Furthermore, the magnitude of stable crack propagation was larger under impulse loading than under sinusoidal fatigue. On the other hand, cracks were slower under impulse loading. Fractographic evidence attributes these phenomena to the nature of craze growth under each loading condition. Kluwer Academic Publishers, 1992 Gomaa A. Department of Mechanical Engineering, Alexandria University, Egypt aut Hamdy A. Department of Mechanical Engineering, Alexandria University, Egypt aut Moet Abdelsamie Department of Macromolecular Science, Case Western Reserve University, 44106, Cleveland, Ohio, USA aut International Journal of Fracture Kluwer Academic Publishers 53/2(1992-01-01), 187-199 0376-9429 53:2<187 1992 53 10704 https://doi.org/10.1007/BF00034671 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00034671 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Gomaa A. Department of Mechanical Engineering, Alexandria University, Egypt aut NATIONALLICENCE 700 1- Hamdy A. Department of Mechanical Engineering, Alexandria University, Egypt aut NATIONALLICENCE 700 1- Moet Abdelsamie Department of Macromolecular Science, Case Western Reserve University, 44106, Cleveland, Ohio, USA aut NATIONALLICENCE 773 0- International Journal of Fracture Kluwer Academic Publishers 53/2(1992-01-01), 187-199 0376-9429 53:2<187 1992 53 10704 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer