| 摘要 |
PURPOSE:To enable a wide-band acoustic emission AE signal to be detected by arranging cylindrical ceramic piezoelectric bodies which have different heights and which are polarized in height direction concentrically within a synthetic matrix. CONSTITUTION:A plurality of cylindrical ceramic piezoelectric bodies 3 are arranged within a synthetic resin matrix 4 so that directions of their heights are nearly in parallel and at the same time a crystalline axis of a piezoelectric body crystalline particle of the piezoelectric bodies 3 is orientated in height direction, thus constituting a polarized synthetic resin - ceramic compound piezoelectric element 1. Therefore, a potential difference is generated on both end faces of the element 1 for a vertical vibration mode only within an AE wave which is propagated in height direction, thus enabling only the vertical vibration mode to be detected, resonance points to appear by the number of types of height of the piezoelectric bodies 3, a detection frequency of the AE wave to be wide, a leading time to be reduced for improving responsiveness and detection sensitivity. Also, since the piezoelectric bodies 3 are arranged in concentric shape, omnidirectionality is achieved and a nearly constant detection sensitivity is obtained regardless of propagation direction of the AE wave. |
