Full surface inspection methods regarding reinforcement corrosion of concrete structures

For reinforced concrete structures a localisation of all significant critical areas can only be done by a full surface inspection. The economic advantages are obvious: uncritical areas have not to be repaired expensively 1 . The first step of the assessment should always be a visual inspection 2 . The range of deterioration causes can be limited and the degree of deterioration may be estimated roughly. The inspection program can be adjusted to the requirements. By means of a full surface potential mapping areas with a high risk for chloride induced reinforcement corrosion can be localised, although no deteriorations are visually detectable at the concrete surface. In combination with concrete cover depth and resistivity measurements areas with corrosion promoting exposure conditions can be localised even if the reinforcement is not yet depassivated. The following publication gives an overview about the essential full surface investigation methods to localise critical areas regarding corrosion of steel in concrete. The selection of methods is based on the inspection procedure given in 2 .     

Case Studies

In this paper, some quite different survey tasks are described, and it can be seen that corrosion surveys will follow a certain scheme of data acquisition (first NDT measurements, than detailed testing on suspect areas), but the individual scope of on‐site measurements may have a vast variety according to the local circumstances, and the interpretation always has to refer to a wider set of information than the data readings only.     

Study of ultrasonic phased array inspection imaging technology for NDT

A research about the ultrasonic phased array imaging principle from A-scan signal to B-scan image for non-destructive testing （NDT） was conducted in this paper, the ultrasonic phased array inspection imaging system used in industrial field was developed and the experiment was performed on the steel testing block by the system with 64 elements, 5 MHz phased array transducer. Experimental results show that the flaws could be accurately detected and the flaws size could be estimated from the B-scan images, and the B-scan images could clearly show the location of the flaws, but the quality of B-scan images needs to be enhanced by digital signal processing and controlling dynamic focusing for improving the image resolution.     

浅谈检化验系统设计在管理体系认证中的延伸及应用

介绍了主要基于管理模式、仪器自动化、智能化及信息化等方面的检化验系统设计思路.阐述了检化验设计在质量管理、环境管理、职业健康安全管理体系认证的重要性.有针对性地提出了工艺设计的原则,与建筑、结构、通风、给排水、电气等专业的接口关系,从本质上提高设计质量,降低设计及后期使用的风险.紧跟行业发展步伐,不断优化设计理念,对接...     

浅谈检化验系统设计在管理体系认证中的延伸及应用

介绍了主要基于管理模式、仪器自动化、智能化及信息化等方面的检化验系统设计思路。阐述了检化验设计在质量管理、环境管理、职业健康安全管理体系认证的重要性。有针对性地提出了工艺设计的原则，与建筑、结构、通风、给排水、电气等专业的接口关系，从本质上提高设计质量，降低设计及后期使用的风险。紧跟行业发展步伐，不断优化设计理念，对接管理体系认证审核及相关需求，延伸设计服务的影响力。     

Local detailed inspection methods regarding reinforcement corrosion of concrete structures

Full surface surveys which are likely to include e.g. a deterioration and potential mapping as well as a cover depth survey, should be the base to identify critical areas which are suspect to be suffering from reinforcement corrosion 1 . Localised assessment in these areas should give further information about the type and extent of deterioration. It should include the determination of the chloride profile beyond the cover depth, the depth of carbonation and a direct visual assessment of the steel reinforcement by breaking away the cover concrete at selected locations. Further valuable information may be collected by determining the water content of the concrete or performing corrosion rate measurements. Within this publication the essential methods for local detailed inspections are discussed regarding the application and interpretation of the results. An overview of the survey procedure is given in ref. 2 .     

NDT techniques for railroad wheel and gauge corner inspection

The development of non-destructive techniques (NDT) techniques for the in-service inspection of railroad wheels and gauge corners was the main activity of the NDT division VIII. 4 at BAM over the last 2 years. For such different components, two different inspection techniques were fundamentally chosen in order to fulfil the end-user requirements. Firstly the inspection of the wheels—rim and disk—should be carried out without dismantling the wheels and using ultrasonic techniques. On the other hand, the inspection of the railroad track surface at a train speed of about 70 km/h should be guaranteed using eddy current techniques. The above-mentioned tasks were a challenge for the lab staff. The accessibility for the wheel inspection was limited due to several impassable barriers such as sand tubes, etc. Eddy current application focused mainly on the detection of head check defects occurring at the gauge corner of the rail. Investigations carried out also showed, that other types of surface defects (e.g. Belgrospis, wheel burns, short-pitch corrugations, etc.) could easily be detected. Some aspects of the inspection system as well as an overview of test results are presented in the current contribution.     

Use of gamma rays in the inspection of steel wire ropes in suspension bridges

Regularity visual inspections are performed on steel wire ropes of suspension bridges. However, because the steel wire ropes were coated with plastic materials, inspectors could not visually detect the deterioration conditions of the ropes. In this paper, radiation tests and electromagnetic testing were compared. The gamma rays used in the radiation tests were employed to develop two assessment techniques, namely the exposure time formula and sensitivity assessment of steel wire ropes. Actual tests showed that such techniques can be adopted to evaluate the defects of steel wire ropes and help engineers improve the safety of suspension bridges.     

Laser ultrasonic testing for near-surface defects inspection of 316L stainless steel fabricated by laser powder bed fusion

The laser powder bed fusion (L-PBF) method of additive manufacturing (AM) is increasingly used in various industrial manufacturing fields due to its high material utilization and design freedom of parts. However, the parts produced by L-PBF usually contain such defects as crack and porosity because of the technological characteristics of L-PBF, which affect the quality of the product. Laser ultrasonic testing (LUT) is a potential technology for on-line testing of the L-PBF process. It is a non-contact and non-destructive approach based on signals from abundant waveforms with a wide frequency-band. In this study, a method of LUT for on-line inspection of L-PBF process was proposed, and a system of LUT was established approaching the actual environment of on-line detection to evaluate the method applicability for defects detection of L-PBF parts. The detection results of near-surface defects in L-PBF 316L stainless steel parts show that the crack-type defects with a sub-millimeter level within 0.5 mm depth can be identified, and accordingly, the positions and dimensions information can be acquired. The results were verified by X-ray computed tomography, which indicates that the present method exhibits great potential for on-line inspection of AM processes.     

Modeling tools for ultrasonic inspection of welds

Developments in quantitative ultrasonic nondestructive testing (NDT) of welds require simulation tools for cost-effective research and engineering works. The present paper reviews the specific developments in modeling of weld inspection at the French Atomic Energy Commission (CEA), made in keeping with the general pattern of CEA in simulation studies of ultrasonic examination. Two models have been developed for several years at CEA for this purpose. One is dedicated to the computation of the ultrasonic field radiated by arbitrary transducers into pieces (possibly anisotropic and heterogeneous) under examination. We specifically discuss how the metallurgical structure and associated elastic properties of welds is taken into account. The other simulates a testing experiment. It accounts for the interaction of the beam with defects (within a piece made of isotropic material) and specimen boundaries and simulates the transducer scan over the piece for synthesizing images comparable with measurements. We specifically discuss the influence of the possible complex geometry of the back-wall of a weld. Examples of application are given. They demonstrate the usefulness of such modeling tools in ultrasonic NDT of welds to study and optimize testing configurations, and to help NDT experts to interpret actual data.     

Application of infrared thermography to the non-destructive testing of concrete and masonry bridges

Within recent years there has been an increase in the use of NDT methods to detect defects and anomalies in various civil engineering structures. Infrared thermography, which has been successfully used in the USA in civil engineering applications, is being increasingly applied in the UK as an NDT technique. For example, the technique is now included in the Building Regulations for the assessment of thermal insulation for all new non-domestic buildings from April 2002.One of the perceived limitations of infrared thermography is that in temperate climates it is too cold to use this technique since there is rarely the extreme solar exposure that has enabled the successful use of thermography to detect render debonding and concrete spalling utilising solar heating. However, with the advancements in modern technology it is now possible to detect smaller changes in temperature (down to 0.08 °C). This paper shows that even with the low ambient temperatures experienced in Europe it is possible to use infrared thermography to identify correctly known areas of delamination in a concrete bridge structure and also to investigate the internal structure of a masonry bridge.     

The monitoring of bridges for scour by sonar and sedimetri

Scour is one of the major causes for bridge failure. This problem represents a heavy burden for the Italian railroads in terms of operating disruption and expense for the restoration of the damaged bridges. Scour failures tend to occur suddenly and without prior warning or sign of distress to the structure. The nature of the failure is often the complete collapse of the entire part of a bridge.Furthermore the pits of erosion tend to fill as soon as the flood begins to decrease, therefore following inspections and measures, in periods of dry weather, cannot furnish indications on the maximum depth reached by erosion during the event of flood.Until recently, there has been little awareness among bridge engineers of the danger of scour, compared to the effort concentrated on structural assessment. Examination into scour on existing structures has been very limited and of doubtful effectiveness. This is reflected in the total absence or at most a passing mention of scour in most bridge inspection and assessment documents.In order to resolve these problems of scour, or to limit the effects, the Italian Railways (F.S.) has provided, up until the recent past, a series of preventive interventions consisting in the consolidation and protection of the bridge foundations. These interventions are expensive and cannot be carried out for all bridges.In recent years the consolidation works have been defined only in the cases of real necessity or where the risk of erosion is high, opting for monitoring systems in other cases. These systems, on the other hand, are able to monitor the levels of scour during a flood and therefore the danger level. Owing to the need to have systems to measure continuously the Italian Railways (F.S.) have installed two experimental monitoring systems on the River Po.The following paper intends to outline the first results of this experiment, which began in 1995: in particular, the bed movement near the pier foundation during a flood.     

离线式带钢双面翻转检查站方案设计及实践

针对某酸轧机组检查站穿带困难、检查效率低、产生废品多、故障率高的问题,开发了一种离线式带钢双面检查站.该检查站新增了带钢翻转装置,将在入口分切剪处完成定尺剪切的带钢试样由两侧压板夹紧,中间可升降皮带机落下,翻转装置将带钢试样张紧,并翻转90°或者180°,实现带钢的双面检查.皮带机两侧布置有可升降、可横移的活动操作平台...     

温室移动机器人运动控制器设计与实现

用运动控制器实现了移动机器人在非结构化、未知环境中的自主导航和定位。运动控制器由PIC单片机、运动控制模块、电机驱动模块、红外传感器模块、通讯模块以及相应的控制软件组成。利用两层前向BP神经网络实现多传器的信息融合。运动控制器在温室移动机器人上进行多次试验。试验结果表明，运动控制器和控制算法是可行的，并具：工程应用的前景。     

Integration of reconfigurable inspection with stream of variations methodology

This paper describes an advanced closed loop quality control methodology for reconfigurable manufacturing systems. The methodology enables rapid root-cause diagnostics for faster ramp-up of reconfigurable systems through integration of the Reconfigurable Inspection Machine (RIM) and the Stream of Variations (SoV) methodology. The RIM enables reconfigurable, rapid, and accurate inspection using non-contact sensors while the SoV methodology is used to quickly analyze the measurements and identify the root-cause of the errors produced during machining.The feasibility of the industrial concept was experimentally validated. A machining error was introduced during machining of an engine head. Measurement information collected by the RIM was processed and used to locate the root-cause of the error using the SoV methodology.     

空间自由曲面精度检验的精定位方法

在空间自由曲面精度检验的自定位方法的基础上,提出了无定位基准的空间自由曲面精定位的基本思路,按工件坐标系的重合可通过几何元素的重合来达到的策略,导出了精定位的算法,并用C语言予以实现。     

护卫传感器在拱顶储罐罐底声发射检测中的应用

大型储罐声发射在线检测越来越得到石化行业的认可,然而对于不同类型的储罐,罐底声发射信号采集方法基本相同,并未考虑储罐的结构差异。提出采用护卫传感器对拱顶储罐底板的腐蚀声发射信号进行采集的方法。通过在罐壁上布置两组传感器,其中一组接收来自罐顶液滴撞击液面产生的声发射信号,即护卫传感器,另一组接收来自罐底的声发射信号,并应用特定的方法有效地滤除拱顶滴液产生的干扰声信号。现场试验结果表明,该方法能有效滤除拱顶储罐罐顶滴液产生的干扰噪声,为后续的数据分析与处理提供了可靠的原始数据。