A test apparatus includes a vibratory body that shakes a device under testing (DUT), a pedestal dedicated to support the DUT and disposed on the vibratory body, and a clamping mechanism operative to selectively clamp the pedestal to the vibratory body and release the pedestal from the vibratory body. The vibratory body and the pedestal define a cavity in which the clamping mechanism is disposed. The clamping mechanism includes a clamp ring and at least one locking element carried by the clamp ring so as to be displaceable in a radial direction relative to the clamp ring, at least one tang facing the at least one locking element in the radial direction, and a piston slidable in an axial direction relative to the clamp ring between a first position at which the pedestal is free from vibratory body and a second position at which the locking element is compressed between the piston and the tang.