Noorsuhada Md Nor

An investigation on acoustic wave velocity of reinforced concrete beam in-plane source

This paper is presented an investigation on acoustic wave velocity of reinforced concrete beam in-plane source based on AE waveform analysis. Pencil Lead Fracture (PLF) was used to generate sudden release of stress at selected source location. Three threshold levels were considered for determining wave velocity in RC beam. It can be concluded that the wave velocity was dependent to the threshold levels, high threshold level would prolong the TOA of the wave and the velocity would be reduced; which the wave travels in the RC beam at velocities in the range 2410 m/s to 4000 m/s. The wave velocity also decreased as the distance from individual sensor to synchronize sensors increased.

An observation of noise intervention into acoustic emission signal on concrete structure

This paper is presented the observation of noise intervention into acoustic emission (AE) signal on reinforced concrete beam based on data recorded in the AEWin software at different pre-set thresholds manually. Two kinds of sources were selected; namely in-plane source and out-plane source. The correlation between threshold levels and number of hits has been observed. It can be concluded that for both AE sources in-plane and out of plane at the lower threshold level, huge hits were produced which including unwanted hits as well as noise. At high threshold level only required data / hits were recorded by AE signals, where the data presented owing to sudden release of stress from pencil lead fracture at selected source location. Thus, it produced lower correlation between threshold levels and a total number of hits recorded as the coefficient of determination for both sources is around 0.8 only and the graph produced is not linear.

Relationship between acoustic emission signal strength and damage evaluation of reinforced concrete structure: Case studies

Relationship between acoustic emission (AE) signal strength and damage evaluation has been reviewed. Several case studies have been referred to get information on that relationship. The notion or any opinion relates to the case study also had been discussed. Reviews of AE signal strength relate to damage evaluation of reinforced concrete structure and other materials are significantly useful for newly researchers.

Active Fatigue Crack Detection and Classification of Reinforced Concrete Beams Using Acoustic Emission

Active crack due to fatigue loading in reinforced concrete beams is a crucial phenomenon and need to be classified. Twelve beams were tested under three point loading with various fatigue loading in conjunction with acoustic emission monitoring. A total of six phases of fatigue maximum loading were performed on the reinforced concrete beams with frequency of 1 Hz, sinusoidal wave and 5,000 cycles for each phase. Two indices of qualitative analysis of acoustic emission signal such as RA value and average frequency were determined to classify the crack of the reinforced concrete beams subjected to the fatigue loading. The relationship of these two indices showed promising results corresponding to the development of active crack in the reinforced concrete beams as the maximum fatigue load increased.

Intensity Analysis Method for Measurement the Damage Severity of Concrete Structure by Utilizing the Acoustic Emission Technique

Evaluation methods such as acoustic emission (AE) are required for assessing the deterioration on concrete structures. This paper gives a brief on the evaluations of the acoustic emission to the health monitoring of reinforced concrete structure beam. Small scale size beam have been used for this investigation and the AE signal processing are the main principal data in this work for assessing by using the statistical technique, which is known as intensity analysis method (IA). This technique is capable to quantify and evaluate the damage severity on concrete structures. Eventually, by using the AE signal strength data, the results indicates are greater instruments in determining the damage mechanism level on concretes structure.

Structural health monitoring through acoustic emission

Abstract Acoustic emission (AE) is one of the structural health monitoring (SHM) techniques to monitor the performance and integrity of the structure when subjected to fatigue loading. AE offers reliable technique for SHM as it can be used to detect and locate damage that may occur in the reinforced concrete (RC) structure. In this chapter, the general application of AE, AE monitoring, and AE analysis based on intensity analysis has been reviewed. A case study relates to the use of AE technique in damage assessment of RC beam under fatigue loading with the aids of AE was investigated and performed in laboratory. A third point loading fatigue test was carried out based on increasing maximum fatigue loading. The classification of fatigue crack for each phase of loading was identified using the intensity of AE signal. It is found that the AE can be used to evaluate the beam condition for SHM as a whole.

The Effects of TiO2 in the Performance of Mortar

Titanium dioxide (TiO2) is a material that contains photocatalysic which acts as self-cleansing agents on a material surface. In the application of TiO2 in the civil engineering construction, it can be mixed with the fresh mortar known as TiO2 mortar. Hence, a study on the characteristic strength of the TiO2 mortar needs to be carried out. Moreover, the optimum dosage levels of the TiO2 in the mortar can be determined. The characteristics of the TiO2 were identified based on the compressive strength and flexural strength at 3, 7, 21 and 28 days. A total of five sets of specimens with different dosage levels were prepared and compared with the control specimen.

Analysis of failure mechanisms in fatigue test of reinforced concrete beam utilizing acoustic emission

The acoustic emission technique is used for monitoring the fatigue failure mechanisms in reinforced concrete beam under three point bending. The analysis was conducted by using the bathtub curve method plotted from acoustic emission data. In this study, the fatigue behavior was divided into three stages. The first stage is involved with the decreasing failure rate, known as early life failure or burn-in phase, the second stage is characterized by constant failure rate and the third stage is called the burn-out phase which is an increase of failure rate. The three parameters used in analyzing is the fatigue behavior for each stage of failure which are severity, signal strength and the cumulative signal strength. From severity analysis, the range of each stage of failure had been determined while from signal strength analysis, the initiation of distribution of crack had been detected through the fluctuation of signal strength. Cumulative signal strength parameter provides a clearer view of the initiation and distribution of crack.

An Investigation of an Acoustic Wave Velocity in a Reinforced Concrete Beam from Out-of Plane and in Plane Sources

© 2013 Md Nor et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. An Investigation of an Acoustic Wave Velocity in a Reinforced Concrete Beam from Out-of Plane and in Plane Sources

B-Value Analysis of AE Signal Subjected to Stepwise Loading

Acoustic emission is an effective damage assessment method in a structure subjected to mechanical loading. Calculation of log-linear slope of the frequency-magnitude distribution of acoustic emission (known as b-value) has been carried out. It is found that the b-valuefor the log frequency-magnitude graph has a good correlation for beam imposed of stepwise loading.It also can be seen that the b-value is decreased as the load increased.