An experimental investigation on the failure of rectangular plate under wedge impact

In the present study, experimental results recorded from a series of tests are presented, which examine the dynamic response and failure of thin rectangular plates struck transversely at the centre by wedges. The rectangular plates are cut from mild steel plates with five different thicknesses of 1.0, 1.5, 2.0, 3.0 and 4.0 mm and two different sizes of 280×190 and 280×130 mm2, to make a ratio of thickness to the average value of length and width ranging from 4.26×10−3 to 17.02×10−3. The impact velocity ranges from 2.45 to 10.45 m/s, producing an impact energy varying from 76 to 2865 J. The length of the drop wedge is chosen as 40 and 120 mm. It has been observed that a through-thickness in-plane tearing (tensile) crack is initiated at two ends of a contact line which is directly under the tip of the wedge. The cracks propagate rapidly inwards along the contact line and finally join together. Once a through-thickness crack is formed along whole contact line, the crack opens further through two out-of-plane tearing (shear) cracks perpendicular to the contact line at each ends of the contact line for severe impact cases. It has been found that the critical impact energy required for the onset of failure varies significantly with the thickness of plates.