Bond failure detection in laminated structures using vibration response

Abstract

Abstract BONDING FLAWS IN A HONEYCOMB-CORE LAMINATED STRUCTURE OR THE LIKE ARE DETERMINED BY COMPARING PHASE OF THE PANEL''S VIBRATIONAL RESPONSE TO VIBRATION-INDUCING PERIODIC FORCES APPLIED TO THE STRUCTURE AT SUBSTANTIALLY THE SAME LOCATION BY A DRIVING TRANSDUCER AND IN MANY CASES BY SIMULTANEOUSLY MEASURING THE AMPLITUDE OF SUCH VIBRATION RESPONSE. TO COMPARE PHASE, THE ELECTRICAL OUTPUT WAVE FROM A VIBRATION-DETECTING TRANSDUCER IS COMPARED WITH AN ELECTRICAL REFERENCE SIGNAL, PHASE-RELATED TO THE ENERGIZING WAVE FOR A VIBRATION-INDUCING TRANSDUCER. WITH THE LATTER TRANSDUCER OF A TYPE WHICH VIBRATES THE PANEL AT TWICE THE TRANSDUCER''S ENERGIZATION FREQUENCY THE PANEL VIBRATION RESPONSE SIGNAL, HOWEVER WEAK, IS DETECTED BY FREQUENCY SEPARATION FROM EXTRANEOUS ENERGY INDUCED IN THE DETECTION CIRCUIT DUE TO THE RELATIVELY LARGE FLOW OF THE POWER ENERGIZING THE VIBRATION-INDUCING TRNSDUCER IN THE IMMEDIATE PROXIMITY TO THE DETECTION TRANSDUCER. PERIODIC INTERRUPTION OF TRANSDUCER ENERGIZATION ADDS FREQUENCY COMPONANTS TO THE PANEL VIBRATION STIMULUS AND THEREBY EXPANDS THE CAPABILITY OF A GIVEN SYSTEM TO PROVIDE MEANINGFUL TESTS OF PANELS OF WIDELY DIFFERENT MATERIALS AND CONSTRUCTION.

Inventors

• 👤 Wayne E Woodmansee
• 👤 Loyd W George

Bibliographic Details