The utility model belongs to the technical field of system discrimination nondestructive test, a invariable energy excitation appearance of pendulum model is related to. Its pendulum energy hammer, circular -arc direction slide rail, two secondary shock trapping apparatus and transmission system who includes sucking disc formula base, constitutes by connecting rod and hammer block two parts, the circular -arc axis intermediate junction that leads the slide rail has pendulum energy hammer, is equipped with horizontal adjusting device on the A of its side, and its side B's central authorities open has the seam, should stitch both sides and be equipped with two secondary shock trapping apparatus in corresponding hammer block department, transmission system one end links to each other with sucking disc formula base, and the other end concreties with the cambered surface C of circular -arc direction slide rail, side B and cambered surface C surface are equipped with respectively along the radian of slide rail direction and the high value of vertical direction. The utility model discloses constitute very simply, can adapt to the on -the -spot continuous operation of laboratory and engineering, and easy operation is easily capable, overcome the random of manual excitation in the past and excitation energy nondeterminacy, have great practical value.