A Gerami - M.Sc. Student, Composite Research Centre, Malek Ashtar University of Technology, Tehran, Iran.
A Davar - Assistant Professor, Composite Research Centre, Malek Ashtar University of Technology, Tehran, Iran
J. E. Jam - Professor, Composite Research Centre, Malek Ashtar University of Technology, Tehran, Iran.
M.R Zamani - Ph.D. Student, Composite Research Centre, Malek Ashtar University of Technology, Tehran, Iran.

Nowadays composite grid-stiffened panels due to their high stiffness and strength to weight ratios and good stability are used in advanced applications such as aerospace industries. These structures may be exposed to damage due to impact loading in practical situations, e.g. handling, transportation and service. In the present study, impact response and damage in composite grid-stiffened cylindrical shells including hoop and helical ribs due to the low-velocity impact of a spherical impactor is investigated using ABAQUS/Explicit code. Validation of the results is achieved by comparing them to the numerical and experimental results available in the literature. The impact response of a composite grid-stiffened cylindrical shell with and without considering the damage effect is obtained and the correspondingcontact force histories as well as induced damage areas are compared. Also, the influence of the possible positions of impact on the shell surface (on the ribs, the rib intersections and the bays) on the impact response and damage are investigated.

Low-velocity impact, Grid-stiffened, Composite, Cylindrical shell, Impact damage