2017 Volume 71 Issue 1 Pages 248-255
In this study, using electromagnetic pulse method, effective input condition for evaluating initial defects of post-installed adhesive anchor bolt which are difficult to be detected by visual inspection is discussed. First, using acryl specimen of which material is homogeneous, turns of exciting coil, applied voltage and electric capacity of pulse current generator were changed for clarifying how the magnetic properties such as magnitude and rise up of magnetic flux density affect the vibration properties of the bolts which simulate defects. Next, using concrete specimen as composite material, effective measurement position and optimum input condition were found for detecting incomplete filling of adhesive in the anchor hole due to vacant portion which are difficult to find by visible inspection. Finally, focusing on the wave energy and frequency response of received signal, it was found that there’s a possibility of detecting the defects effectively using the input conditions that the magnitude of magnetic flux density is large at the head of bolt, and the rise up velocity of magnetic flux density is large.
