METHOD AND DEVICE FOR IMPACT TESTING Russian patent published in 2005 - IPC

FIELD: test equipment.

SUBSTANCE: longitudinal strain with preset characteristics is formed in wave-guide. Parameters of longitudinal strain as well as acceleration ahead and behind test object are registered. Transfer functions from impact source to test object are measured. Strain wave is formed in wave-guides with no mounted test object, which is substituted, by third wave-guide. Impact is realized by means of detachable pyrotechnical device. Movement of wave-guide and detached parts of pyrotechnical device provided with fixing knots are registered as well as maximal shifts of the devices are registered after pyrotechnical devices operates. Accelerations and deformations in wave-guide are registered in several points ahead and behind point of placing of test object. Force impulse is achieved at point of operation of pyrotechnical device is calculated from preset relation. Force impulse from impact source, amplitude and impact spectra which act on test object are derived. Received values are compared with values achieved before and if they don't coincide the impact is corrected by means of increase in mass of parts of board detaching from the wave-guide - for the purpose intermediate member is introduced between impact source and wave-guide. Test object is mounted by substituting third wave-guide and test object is subject to shock loading. By using accelerations and deformations registered at first and second wave-guides when test object was mounted, force pulse is calculated by pre-described relation which pulse acts on first and second wave-guides separately. Damping properties and impact strength of test object is judged from changes in force impulse and amplitude and impact spectra. Test board has device for shock loading, two wave-guides and test object mounted between device for shock loading test object. There are cups provided with flanges at edge parts of wave-guides at the sides adjacent to test object where accelerometers are mounted. Deformation pick-ups and photogrammetric marks are mounted at wave-guides and at outer sides of cups. Impact source has to be detaching pyrotechnical device that is covered with protection casing made in form of ballistic pendulum hung over at ropes and made in form of hollow cylinder provided with bottom. Photogrammetric marks are located at external surface of cylinder. There are lugs for mounting additional weights. Threaded hole for removable insertions is made in the bottom. Wave-guides go through centers of cylindrical discs onto which accelerometers are mounted. Axes of sensitivity of accelerometers are parallel and perpendicular to axes of wave-guides. Deformation pick-ups are disposed in the middle between discs. Discs are rigidly tightened with wave-guides at edge parts of which wave-guides there is thread for mounting removal insertion to provide standard detaching of pyrotechnical device.

EFFECT: improved reliability of results of measurement. 6 cl, 7 dwg