The Largest Open Access Portal of Nondestructive Testing (NDT)

For owners of structures reinforcement corrosion is difficult to manage as the industry does not provide clear guidelines on the implications of reliability at concept design and they lack objective tools to give information on the actual corrosion state of the embedded steel during the structures life. With better information at concept owners could determine the quality level to target and instigate appropriate maintenance measures. With better information through the structures life they could take remedial actions well before damage appears and their spending on repairs would be reduced. The paper discusses the application of risk assessment to serviceability design and tools that can be used to assess deterioration during each part of a structures life. Reference is made to risk assessment on actual projects and the use of embeddable half cells, corrosion rate probes and corrosion activation monitors.

Non-Destructive Testing (NDT) is finding increasing applications in numerous industries. This paper focuses, first, on the use of NDT in selected industries and its critical nature in the safe operation of plant machinery and structures. Secondly, an overview of the education and training in South Africa is discussed. The qualification offered at the Vaal University of Technology (VUT) and its impact on the NDT profession in South Africa is reflected upon. Thirdly, the reward of an NDT career is contrasted with the perceived low profile of NDT amongst practicing engineers in South Africa. Lastly, an argument for the urgent need of a legislative framework for the regulation and recognition of NDT qualifications and certification in South Africa is advanced. It is emphasized that this is a necessary measure to have accountability and a code of ethics entrenched in this growing profession.

This paper describes an evaluation of promising, mobile non-destructive inspection (NDI) methods for the in-service inspection of composite aerospace structures. The evaluation makes use of carbon fibre reinforced specimens representative for primary composite structures in current and next generation aircraft and helicopters. The specimens comprise solid laminates and sandwich structures with/without stiffeners, and include relevant damage types such as impact damage, interply delaminations and disbonds. A range of promising, mobile NDI methods are evaluated including visual inspection, vibration analysis, ultrasonic inspection (including different phased array methods), shearography and thermography inspection. An important aspect of the evaluation is the capability of the NDI methods for the detection, sizing and depth estimation of the defects present in the specimens. Further evaluation parameters are the portability of equipment, field of view, couplant requirements, speed of inspection, level of training required and the cost of equipment. The paper gives an overview of the advantages and limitations of the different NDI methods, and concludes with general guidelines for the in-service inspection of composite aerospace structures.