| 摘要 |
PURPOSE:To reliably and rapidly detect a gap part of a low-concentration member, by a method wherein a mechanical vibration is applied to a plate body whereto a low-concentration member is firmly adhered, and from an electric signal thereof a power spectrum of a frequency is found to compute and process it. CONSTITUTION:A mechanical vibration is applied from a vibrating part 5 to an object to be measured in which a space between an iron plate and a plastic plate is filled with urethane foam. The vibration is converted into an electric signal by a vibration detecting part 1, and a signal indicating a power spectrum of a frequency is outputted by a frequency analyzing part 3 to store it in a computer control part 4. If a gap part is present in a low-concentration member, a power spectrum thereof is such that, as indicated in a diagram, a resonnance frequency 25 showing a maximum level moves to a low frequency side. The control part 4 computes integral values A1 and A2 and finds a ratio between them, and compares it with a reference value to decide the presence of a gap. This permits the reliable and rapid detection of a gap part. |
