• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.392-395
• /
• 2004

When a concrete member is damaged by fire accident, it can lose its strength. And the degradation rate of losing its strength affected by many environmental conditions. But there is few research for equation for strength evaluation of fire-damaged concrete. Besides, it is impossible to destruct structural member from the building for the evaluation. So, I will suggest a new equation for strength evaluation of fire-damaged RC beam using non-destructive test. For this purpose, the researchers are exploring the performance of non-destructive testing methods using Ultrasonic test, Schmidt Hammer test and Coring test against fire damaged concrete specimen.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.65-68
• /
• 2006

This study is aimed to investigate the strength variation of fire-damaged reinforced concrete column with polypropylene by non-destructive test. It is studied to infer the recovery degree of residual strength of fire-damaged concrete. For measuring the surface hardness of RC columns, Schmidt hammer test is used. Testing is performed four-times: before fire test, directly after fire test, after 30 days and after 4 months.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2002.05a
• /
• pp.191-194
• /
• 2002

The tensile properties of materials can be obtained just in accordance with conventional tensile testing methods which are described in several standards. However, the standard testing methods cannot be applicable due to the destructive testing procedure and specimen size requirement for some cases including on-service facility materials. Therefore, simple, non-destructive and advanced indentation technique was proposed. This test measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation and fracture. In this paper, the research trend of non-destructive evaluation of tensile properties using advanced indentation system and its application fields are reviewed and discussed.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2015.05a
• /
• pp.78-79
• /
• 2015

For estimating compressive strength of concrete, non-destructive test has conducted generally. It used experimental equation to calculate compressive strength from construction. This study investigated experiment to apply non-destructive test, based on fresh property, compressive strength and ultrasonic pulse velocity of high performance concrete. And it conducted to compare various proposed equation.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.11a
• /
• pp.5-6
• /
• 2014

For estimating compressive strength of concrete, non-destructive test has conducted generally. It used experimental equation to calculate compressive strength from construction. This study investigated experiment to apply non-destructive test, based on fresh property, compressive strength and ultrasonic pulse velocity of high performance concrete. And it conducted to compare various proposed equation.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2006.05a
• /
• pp.155-158
• /
• 2006

Deduction of compressive strength in concrete members is very important to decide stability of structures. In this study, we compare the compressive strength of concrete between nondestructive test done to the building which was to be demolished at residential reconstruction site and destructive test of core specimen from the site. The result is more reliable because ore can compare the measurement of nondestructive tell with the result from destructive test using drilled cores. Compressive strength of each material was calculated with the result of rebound number test. In addition, we performed ultrasonic test for another result of compressive strength. And we made a comparative study of compressive strength of concrete drawn from both nondestructive and destructive tests.

• Journal of Auto-vehicle Safety Association
• /
• v.13 no.2
• /
• pp.50-56
• /
• 2021

The purpose of this study is to investigate vulnerable parts of tower crane structures by analyzing extensive non-destructive test data. Approximately ten percent of domestically registered tower cranes were inspected by using magnetic particle inspection. The testing was carried out as advised in KS B 0213. The non-destructive results was analyzed with respect to jib types, age and crane size. As a result, the number of crack occurrences were the largest in mast parts, followed by main jib part. Moreover, it was found that turntables were important parts deserved to be noticed at the perspective of safe maintenance.

• Geomechanics and Engineering
• /
• v.25 no.4
• /
• pp.317-330
• /
• 2021

This paper reports the results of advanced data analysis involving artificial neural networks for the prediction of the unconfined compressive strength of granite using only two non-destructive test indexes. A data-independent site-independent unbiased database comprising 182 datasets from non-destructive tests reported in the literature was compiled and used to train and develop artificial neural networks for the prediction of the unconfined compressive strength of granite. The results show that the optimum artificial network developed in this research predicts the unconfined compressive strength of weak to very strong granites (20.3-198.15 MPa) with less than ±20% deviation from the experimental data for 70% of the specimen and significantly outperforms a number of available models available in the literature. The results also raise interesting questions with regards to the suitability of the Pearson correlation coefficient in assessing the prediction accuracy of models.

• Electronics and Telecommunications Trends
• /
• v.33 no.3
• /
• pp.59-69
• /
• 2018

Terahertz (THz) imaging and spectroscopy have been developed as non-destructive testing methods for various industrial applications. However, they have not been widely adopted in real applications owing to a high system price and the large size of conventional THz time-domain spectroscopy systems, which are based on ultrashort optical pulse lasers. Recently, various types of compact THz emitters and detectors have become available. As a result, THz non-destructive test (NDT) systems have become viable solutions. Herein, we briefly review the recent advances in THz NDT techniques adopting continuous-wave THz systems, including our recent results of a THz-based waterproof test system and an electrical connection inspection system for car manufacturing.

• Journal of Welding and Joining
• /
• v.17 no.6
• /
• pp.100-107
• /
• 1999

In this paper, we deal with the speckle noise reduction and parameter estimation of ultrasonic NDT(non-destructive test) signals obtained during weld inspection of piping. The overall approach consists of three major steps, namely, speckle noise analysis, proposition of wavelet domain AR(autoregressive) model and flaw detection by proposed model parameter. The data are first processed whereby signals obtained using vertical and angle beam transducer. Correlation properties of speckle noise are then analyzed using multiresolution analysis in wavelet domain. The parameter estimation curve obtained using the proposed model is classified a flaw in weld region where is contaminated by severe speckle noise and also clear flaw signal is obtained through CA-CFAR threshold estimator that is a nonlinear post-processing method for removing the noise from reconstructed ultrasonic signal.