Method for non-destructively testing construction elements

• US 4,383,446 A
• Filed: 03/27/1981
• Issued: 05/17/1983
• Est. Priority Date: 04/02/1980
• Status: Expired due to Fees

• Current Assignee: Eckhard Roeder
• Original Assignee: Eckhard Roeder
• Inventors: Flake, Wolfgang, Roeder, Eckhard
• Primary Examiner(s): Kreitman, Stephen A.
• Application Number:
  US06/248,601
• Time in Patent Office: 781 Days
• Field of Search: 73/579, 73/620, 73/624, 73/629, 73/1 DV
• US Class Current: 73/579
• CPC Class Codes: G01N 2291/02827 Elastic parameters, strength or force
• CPC Class Codes: G01N 2291/0289 Internal structure, e.g. defects, grain size, texture
• CPC Class Codes: G01N 29/12 by measuring frequency or resonance of acoustic waves measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00
• CPC Class Codes: G01N 29/4454 Signal recognition, e.g. specific values or portions, signal events, signatures
• CPC Class Codes: G01N 3/32 by applying repeated or pulsating forces

Abstract

A method of non-destructively testing construction elements accessible from only one side by measuring their resonant oscillations to detect flaws in them without scanning. A test piece (1) is excited with a narrow band ultrasonic oscillation whose frequency is varied; the amplitudes of the resonant oscillations are measured and plotted in an xy coordinate system against the frequency of the exciting ultrasonic oscillations.

Claims

1. Method for non-destructively testing construction elements by measuring their resonant oscillations, comprising:

exciting a test piece (1) with a narrow band ultrasonic oscillation, varying the oscillation frequency, measuring the amplitudes of resonant oscillations in the test piece, and plotting said resonant amplitudes in an xy coordinate system against the frequency of the exciting ultrasonic oscillations, wherein resonant amplitude deviations are directly measured by a constant voltage decoupling of the measured amplitudes of the resonant oscillations, and amplitude envelopes are formed.

2. Method according to claim 1, wherein the frequency of the exciting ultrasonic oscillation is varied in stages, and limit values for the amplitudes of the resonant oscillations of the construction element are set for each stage for purposes of fully automatic evaluation.