抄録
Exterior tile cladding can suffer debonding or adhesive failures as it ages. Failures that lead to cladding tiles falling from the building are highly dangerous for people passing beneath, and consequently it is vital to be able to identify debonding defects at an early stage to prevent tiles falling. This study was performed to develop high-precision apparatus for the efficient debonding detection of debonding. This paper presents the results of investigations into detection methods using impact acoustics.
Initially, eight exterior-tile wall specimens were prepared with artificially debonded areas. The type of tiles, bonding materials, debonding interface and debonding depth were different for each sample. Percussion tests were carried out by three professional testers, and diagnostic tests were also performed using two types of existing debonding detecting apparatuses. The professional testers had an error rate of up to 40% in differentiating between bonded and debonded areas, while the error rate using the detecting apparatuses was up to 20 percent. These results reveal the effectiveness of using debonding detecting apparatus, but also the need for clear criteria for the apparatus, as well as the need to improve accuracy of the apparatus for objective and accurate diagnosis of debonding,
Next, a prototype apparatus which has a highly efficient impact mechanism with a solenoid actuator and a microphone was manufactured. The apparatus was then used to examine suitable analysis methods, using impact acoustics, for detecting debonding and effective method for predicting depth of the debonding. As a result, relative maximum amplitude derived from impact sound waveform detected debonding areas correctly. In addition, the interval between the first and the second peaks of the recorded impact sound waveform showed the possibility of predicting debonding depth properly.
Further research will be continued in order to establish more effective and accurate parameters and their criteria.
