Simple Non-destructive Test Research Articles

Development of a machine learning model for on-site evaluation of concrete compressive strength by SonReb

Coring or destructive testing is typically the default choice for the evaluation of concrete compressive strength in reinforced concrete (RC) structures. However, it can be impractical and/or not representative of all areas of interest in a structure. While various non-destructive test (NDT) methods can be correlated to concrete strength, the accuracy of any single NDT used for this purpose is generally low. The SonReb method, which combines ultrasonic pulse velocity readings and rebound number, has been shown to have improved accuracy over single test methods. However, empirical SonReb equations, calibrated to specific datasets using regression analysis, cannot necessarily be applied to concrete from other sources without introducing significant errors. This study presents a practical machine learning (ML) model for on-site concrete strength prediction. A large database was created from available literature along with new experimental test data. Three different ML models based on an adaptive neuro-fuzzy inference system (ANFIS) were developed along with a graphical user interface application to facilitate its use in the field. In addition to the ML models, linear and non-linear regression analyses were also conducted and compared with existing equations in the literature. The accuracy of each model was subsequently validated against core samples extracted from a reinforced concrete slab. The results show that the proposed ML model and non-linear regression provided the most reliable predictions of concrete strength of the validation specimen with a mean absolute error of less than 10 % compared with twelve core samples. The findings suggest that ML can be a potential tool to evaluate the in-place compressive strength of RC structures in combination with simple NDT methods.

Reliability Analysis and Life Prediction of Aging LNG Unloading Arms Based on Non-Destructive Test Data

Unloading arms (ULAs) among seaport infrastructures are susceptible to deterioration posed by the effects of harsh marine environmental conditions. During infrastructure’s service life, the deterioration of structural integrity may increase the risk of failure of infrastructure, and should be taken into account during structural reliability assessment. In this study, a simple non-destructive test (NDT) was employed to examine the structural deterioration of ULAs which were installed over 30 years ago. Then, these aging ULAs were modeled by the finite-element program, using non-destructive test data to update the thickness dimensions of structural members. Next, a reliability assessment was conducted based on the stress distribution of the main structural components under external loads, which are calculated by their relation to wind speed. Moreover, the time-dependent reliability index curve was also built by considering the deterioration function to predict the failure probability of the particular components during the remaining lifetime. The study revealed that the present condition of the ULA system was satisfactory for current loading conditions. A reliability index predicted with deteriorations factors may be a rational and appropriate approach for the assessment of aging structures needed for efficient infrastructure management.

Estimating the Concrete Compressive Strength by Using the Concrete Ultrasonic Pulse Velocity and Moduli of Elasticity

Developing a non-destructive method which delivers fast, accurate and non-invasive results regarding the concrete compressive strength, is an important issue, currently investigated by many researchers all over the world. Different methodologies, like using the simple non-destructive testing (NDT) or the fusion of different techniques approach, were taken into consideration in order to find the optimal, most suitable method. The purpose of this paper is to present a new approach in this direction. The methodology consists in predicting the concrete compressive strength through ultrasonic testing, for non-destructive determination of the dynamic and static moduli of elasticity. One important, basic assumption of the proposed methodology considers values provided by technical literature for concrete dynamic Poisson’s coefficient. The air-dry density was experimentally determined on concrete cores. The dynamic modulus of elasticity was also experimentally determined by using the ultrasonic pulse velocity (UPV) method on concrete cores. Further on, the static modulus of elasticity and the concrete compressive strength can be mathematically calculated, by using the previously mentioned parameters. The experimental procedures were performed on concrete specimens, namely concrete cores extracted from the raft foundation of a multistorey building; initially they were subjected to the specific NDT, namely ultrasonic testing, and the validation of the results and the proposed methodology derives from the destructive testing of the specimens. The destructive testing is generally recognized as the most trustable method. The precision of the proposed method, established with respect to the destructive testing, revealed a high level of confidence, exceeding 90% (as mean value). It was noticed that even the cores with compressive strength outside of mean range interval (minimum and maximum values) presented high rate of precision, not influencing the overall result. The high rate of accuracy makes this method a suitable research background for further investigations, in order to establish a reliable NDT methodology which could substitute the very invasive and less convenient, destructive method.

脱塩器内部品のリスクベースメンテナンス方法にもとづく最適な保全周期設定の研究

Maintenance planning of stationary equipment in the petroleum plant is based on information of maintenance inspection history, daily routine inspection history and operation monitoring trend recording, and level evaluation of likelihood of damage and degrees of influence of damage when damage occurs is performed using failure mode and effects analysis (FMEA) worksheet. Risk controls such as avoidance and removal, reduction, dispersion and tolerance are taken in accordance with the degrees of influence. While Electro-Dynamic Desalter (EDD) which is important to corrosion reduction of the atmospheric distillation unit is a pressure vessel, EDD is treated as electrical equipment since the internal structure in which 124 or more electrode plates are set has a function of agglomerating and removing fine water droplets which are impurities in crude oil by applied voltage 20-40kV.References concerning risk-based maintenance (RBM) for a large number of running EDD all over the world cannot be found. Damaged parts of EDD internals both in and outside Japan were sampled, and analysis in the viewpoint of failure physics, remaining life evaluation technology for non-metallic materials by a simple non-destructive testing method and knowledge of setting optimum maintenance period are obtained. The details are therefore described in this paper.

Dielectric Properties and Compositional Analysis of Banana (Musa sapientum Linn) and Relationship to Ripening

Abstract. The compositions of bananas (Musa sapientum Linn) of various ages after flowering, from young bananas to mature unripe and ripe bananas, were analyzed and their dielectric properties were investigated by using two dielectric plates in a parallel model. Mathematical analysis of the measurement system was proposed and verified for reliability and accuracy. The dielectric properties were measured using a precision impedance analyzer in the frequency range of 100 Hz to 1 MHz. Average relative permittivities of about 20 to 40 and 13 to 23 were obtained for fresh and dried bananas, respectively. The results clearly indicate that the high moisture content and the ripening stage affect the relative permittivity with a p-value from ANOVA of less than 0.0005. The increase in relative permittivity after ripening and the carbohydrate content were found to have a linear relationship with an R2 value of 0.958. Continuous measurement of mature unripe bananas at different ripening stages showed that the relative permittivity was rather constant with a value of about 30, and it increased rapidly after the bananas ripened fully. The high increase in the relative permittivity correlated with the increase in carbohydrate content during ripening in combination with the high moisture content of fresh ripe bananas. The results and measurement techniques developed from this study could be used as a simple nondestructive test for indication of banana ripeness and the changes in carbohydrate content during ripening, and it is expected that similar techniques could be beneficial for further applications with other kinds of crops.

Thermocatalytic decomposition of dimethyl methylphosphonate (DMMP) in a multi-tubular, flow-through catalytic membrane reactor

The potential for the use of chemical weapons has increased in recent times. The successful use of a flow-through catalytic membrane reactor (FTCMR) as a protection system against a chemical warfare agent (CWA) was recently reported by this group. This FTCMR, employing a single catalytically active mesoporous membrane, was applied for the destruction of dimethyl methylphosphonate (DMMP), which is known as a chemical precursor (and used to simulate its characteristics) for Sarin (GB), a toxic CWA. In this paper, results are reported of efforts to scale-up this lab-scale FTCMR towards practical individual protection (IP) and collective protection (CP) applications. A multi-tubular FTCMR (MFTCMR) has been developed and tested towards the destruction of DMMP. The MFTCMR has been shown quite effective, providing extended protection periods against this CWA simulant. A key part of the research effort focused on improving the preparation of the catalytically active membranes to prepare membrane bundles with reproducible transport characteristics and reactivity. A key challenge for the large-scale production of such devices, furthermore, remains the development of a simple non-destructive test that assures that the produced parts are appropriate for the proposed application and that they continue to remain active during their shelf-life prior to their use. As part of this effort a simple propane-in-air light-off test was studied, which was shown capable to track the reactivity and performance of the MFTCMR.

Effects of calcined perlite powder as a SCM on the strength and permeability of concrete

The use of Supplementary Cementitious Materials (SCMs) has been developed to reduce the environmental pollution and the consumption of precious natural resources in the concrete industries. Furthermore, use of these materials usually reduces the cost and enhances the durability of concrete. Perlite, as a natural glassy volcanic rock, is easily accessible in the most parts of the world; besides, previous studies have demonstrated that Calcined Perlite Powder (CPP) could be used as an effective SCM. However, few studies have investigated the impact of it on different properties of concrete. In this study, the influence of partial replacement of Ordinary Portland Cement (OPC) with CPP on the compressive strength and concrete resistance to chloride ions ingress is investigated. For this purpose, eight different concretes by two w/b ratios and three levels of OPC replacement were cast, cured, and tested at 7, 28 and 91days. Results reveal that although replacement of OPC with CPP insignificantly decreases the compressive strength of concrete, the permeability is highly improved. Besides, it was known that surface resistivity as a simple non-destructive test, even in concretes containing CPP, could reliably predict the rapid chloride permeability and the migration coefficient of concrete.

Improved assessment of fibre content and orientation with inductive method in SFRC

The inductive method is a robust and simple non-destructive test to assess the content and the distribution of steel fibres in FRC. Despite the advantages in comparison with other methods, further studies are still needed to define the accuracy, the theoretical basis and the equations for the conversion of the inductance into fibre content and distribution. In fact, although the test provides an indirect estimation of the fibre distribution, currently no equation exists for the assessment of the orientation number, which is a valuable parameter for the design of structures. The objective of the present paper is to address this issue. Initially, the theoretical basis for the calculation of the fibre content is provided. Then, alternative equations are deducted for the fibre contribution and for the orientation number. Different experimental programs and finite element numerical simulations are conducted to evaluate the accuracy of the method and to validate the proposals. The results indicate that the equations currently used may lead to errors of up to 24 %. Instead, the formulation proposed here shows errors far below 2.6 %, allowing the prediction of the orientation number in all directions with a high accuracy. This opens up a new field of application for the test and represents an advance towards the characterization and the quality control of SFRC.

G170021 反発硬度計を用いた化学装置用プラスチックの特性および劣化評価

In order to efficiently manage chemical equipment made of organic materials, it is necessary to develop simple non-destructive testing method for organic materials. Evaluation of defect detection was investigated of amine-based epoxy resin, using the same resin and Carbon Fiber Reinforced Plastic. In this study, using a Rebound Type hardness tester. Prepared by the plate thickness 2mm, 4 mm epoxy resin test specimen, 6 mm, was performed by using a hardness measurement rebound. Plate thickness 2 mm CFRP, were measured in the same manner as prepared in 4ply, 5ply, 6ply, also a carbon fiber mat. Difference between the HL hardness could be confirmed by the difference of the plate thickness. This indicates that the defect can be used to detect organic material using a hardness tester rebound is possible.

콘크리트의 탄성계수 및 감쇠비 결정에 대한 충격공진시험 적용

콘크리트의 탄성계수 결정을 위해 다양한 시험기법이 사용되고 있다. 충격공진시험(IR: impact resonance test)은 비파괴시험으로서 간편한 시험장치와 단순한 시험방법이며 반복성이 뛰어나다. 또한 충격공진시험은 탄성계수 뿐만 아니라 감쇠비 결정이 가능하다. 이 연구에서는 콘트리트 시편에 대한 충격공진시험의 다양한 영향요소(시편거치 방법, 충격하중원의 특성, 신호획득 속도 등)를 평가하고 최적의 시험조건을 제시하였다. 이 연구에서 적용한 모든 시험조건 범위에서 충격공진시험에서 측정된 결과의 변동량은 공진주파수 결정에 있어서 ±0.3%, 감쇠비 결정에 있어서 ±10.0%로 나타났다. 충격공진시험에서 결정된 탄성계수와 정적시험에서 결정된 탄성계수를 변형률 크기를 고려하여 비교하면 비교적 서로 잘 일치함을 확인하였다.

RELATIONSHIP BETWEEN ULTRASONIC PULSE VELOCITY AND STANDARD CONCRETE CUBE CRUSHING STRENGTH

In Jordan as well as in most countries, many concrete structures are becoming old. The question of whether they are safe to be utilized by people or is it feasible to spend money to rehabilitate them, requires conducting a quality survey to assess the integrity of all critical structural items without undermining the safety of the structures. Moreover the nondestructive testing is beneficial for the quality control of new constructions. One of the most effective and least expensive techniques is using Ultrasonic Pulse Velocity (UPV), utilizing Pulse ultrasonic nondestructive indicator tester (Pundit) - a simple non-destructive testing device – that is used to assess the integrity of the structures without causing any damage. Thus the aim of this study is to give forth a mathematical relationship that relates UPV with standard concrete cube crushing strength ( cu f ) in a step to reinforce the credibility of nondestructive compressive strength investigations on concrete containing local materials. To accomplish this task, 135 standard concrete cubes of 150 mm dimensions were prepared using various concrete mixes in order to cover all types of concrete locally produced. The UPV and the relevant crushing strength for each cube were documented. Regression analysis was carried out to study the correlation among observed data. Finally a mathematical relationship between Pundit readings and the corresponding cube compressive strengths was derived.

Detection of Hermetic Defects in HTS Wire

There are important applications of HTS in which the wire comes into direct contact with liquid coolants. If the coolant penetrates into the wire filaments through small leakage paths then a catastrophic failure may result upon warming of the wire as the liquid rapidly expands into a gas. It is therefore desirable to have a simple nondestructive test for hermeticity of long lengths of tapes. A number of tests for detecting hermetic defects with an emphasis on their feasibility within a manufacturing context are considered. The most promising technique is a colormetric test using ammonia as a tracer gas. We correlate results from colormetric tests with pressurized liquid nitrogen testing.

Sea defences: Geophysical and NDT investigation techniques

Geophysical survey techniques provide a cost effective and direct method for locating anomalous features and zones of weakness within sea defences and man-made structures located at the sea-land interface. Combined with simple non-destructive testing (NDT) techniques the presence of cavities, zones of weakness and salt water ingression may be detected. This paper reviews available techniques and illustrates the application of several techniques to particular structural situations such as the detection of voids and material changes beneath sea defences and promenades and the monitoring of zones of weakness in a stone pier. With the recent advances in electronics, improved instrumentation is becoming available which, with the developments in computer based interpretation software, is leading to several geophysical techniques being far more applicable to site investigation prior to the construction of new structures and the long term monitoring of existing structures for possible in-situ defects.

A simple pull-out test for in situ determination of early strength of concrete

The aim of the work reported was to develop a simple non-destructive testing method for monitoring strength development between 5 MPa and 15 MPa for form stripping in industrialized building. Existing test methods are briefy reviewed and requirements for the test summarized. A simple pull-out test has been developed using wood-screws, which can be inserted in critical areas of the element during casting. In a laboratory investigation the deflect of different variables on the pull-out load-standard cube strength relationship was examined. These included cement content, water/cement ratio, slump, mode of compaction and accelerated heat curing. Evaluation of test results indicates low dependence of the proposed method on mix proportions, and suggests reasonable repeatability. Further tests are proposed to refine the method for various field applications.