An experimental study into the dynamic plastic behaviour of wide beams and rectangular plates

An experimental programme was undertaken into the dynamic behaviour of wide beams and rectangular flat plates which were fully clamped and axially restrained at two ends. The initial energy of the uniformly distributed impulsive loads applied to the specimens was considerably greater than the corresponding static elastic strain energy capacities. Over 50 tests were conducted on mild steel and aluminium 6061-T6 specimens which had various L/H and L/B ratios. It appears that the permanent transverse deflections at the center of the beams and plates are essentially independent of the aspect ratios for L/B between 1 and 5. It is shown that an increase in strain-rate sensitivity of the material from which a wide beam or plate is made leads to smaller permanent deflections which agrees with earlier studies on beams. However, this effect is less important than the influence of geometry changes or finite-deflections when W0/H > 1 approximately. It is concluded that the predictions of rigidplastic theories for fully clamped beams give reasonable engineering estimates of the permanent transverse deflections provided the influence of geometry changes and material strain-rate sensitivity is retained when appropriate.