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The influence of cutout shape upon the buckling stability of multilayered rectangular epoxy plates reinforced by glass fiber, with different orientation angles is investigated. U-shaped cutouts are made on the long sides symmetrically. The investigated plates are simply supported on the loaded edges (i.e. short sides) and free on the unloaded edges. The plates without cutouts are examined theoretically to confirm experimental and Finite Element (FE) results. The FE and experimental results are found out for different U-shaped cutouts sizes. U-notch shape effects are examined depending on notch depth and notch root radius. According to results, the effect of notch depth is stronger than that of the notch root radius on buckling loads of plates. But, in some cases, although plates containing U-notch, no reduction is obtained in buckling loads. Obtained results with experimental, theoretical, and FE are in good agreement with each other.

a b s t r a c tThis study focuses on the ballistic performances of 1 and 2 mm-thick and 2 Â 1 mm-thick cold rolled sheet metal plates against 9 mm standard NATO projectile. The velocity of the projectile before and after perforation, the diameter of the front face deformation, the depth of the crater and the diameter of the hole were measured. The fracture surfaces of the plates near the ballistic limit were also microscopically analyzed. The highest ballistic limit was found in 2 mm-thick plate (332 m s À1 ) and the lowest in 1 mmthick plate (97 m s À1 ). While, the ballistic limit of 2 Â 1 mm-thick plate decreased to 306 m s À1 . Typical failure mechanism of the projectile was the flattening and mushrooming at relatively low velocities and the separation from the jacket at relatively high velocities. In accord with the ballistic limits, 2 mm-thick target plate exhibited the highest hardness value. Microscopic investigations showed the significant reductions in the grain size of the targets after the test.

Elastic–plastic stress analysis is carried out on steel fiber reinforced thermoplastic matrix laminated beams loaded by bending moment. The beam is composed of four orthotropic layers, perfectly bonded and symmetrically arranged with respect to the x-axis. The orientation angles are chosen as (90°/0°)s, (30°/30°)s, (45°/45°)s and (60°/60°)s. The composite material is assumed to be linearly hardening. x residual stress component is found to be highest at the upper and lower surfaces. However, when the applied bending moment is increased, the plastic region is further expanded towards middle plane from the upper and lower surfaces of the beam and so x residual stress component is found to be highest at the elastic and plastic boundaries. The plastic flow is obtained to be maximum at the upper and lower surfaces for (30°/30°)s orientation. The transverse displacement is obtained to be highest at the free end for (90°/0°)s orientation.