ISO 16837:2019 pdf download.Non-destructive testing — Acoustic emission testing — Test method for damage qualification of reinforced concrete beams
1 Scope
This document specifies a test for damage qualification of reinforced concrete beams in services as bridges, docks and buildings.
2 Normative reference
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 12716, Non-destructive testing — Acoustic emission inspection — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 12716 and the following apply.
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3.1 AE activity
occurrence of AE hits or counts under stressed conditions in concrete
3.2 Kaiser effect
little AE activity (3.1) observed until the maximum load of the previous stage is surpassed when stresses are applied, removed and then reapplied to a material or a structure
3.3 Felicity ratio
ratio of the load at which emissions start to the previous maximum load when stresses are applied,removed and then reapplied to a material or a structure
Note 1 to entry: This shows the ratio of the degree of conformity of the Kaiser effect (3.2).
The internal noise of the amplifier shall be inherently low and less than 20 µV (26 dB AE for 0 dB AE = 1 µV) as the peak voltage converted by input voltage. The amplifier shall be also robust enough against the environmental conditions and be protected properly. The frequency range shall be determined prior to the measurement, taking into account the performance of AE sensor and the amplifiers. A suggested range in concrete is from around 10 kHz to 100 kHz, because such higher frequency components as over 1 MHz readily attenuate in concrete. For signal analysis, AE parameters of AE count or AE hit shall be detected and processed. The measurement system shall be able to obtain time information along with AE data. In addition, such external parameters as load, strain and so forth are preferably recorded in the system, which can be equipped with enough memory to record the data measured. It is preferable that all the data recorded be analyzed digitally by computer.
5 Environmental noises
In advance of the AE measurement, the noise level shall be estimated. Then, counteract against external noises, wind, rain, sunshine and so forth shall be conducted to decrease the noise level as low as possible. In the case that the noises have similar frequency contents, amplitudes to AE signals or sources of the noises are unknown, characteristics of the noises shall be estimated prior to the measurement. Based on this result, separation of AE signals from the noises shall be achieved. In this respect, the use of filters is applicable after determining the proper frequency range. Normally, to eliminate mechanical noises due to vibrations, traffics and so forth, a high-pass filter over several kHz is useful. Elimination of electrical noises is made by a low-pass filter over around 100 kHz.
ISO 16837:2019 pdf download
