scholarly journals Risk Based Inspection of Jackets Submitted to Through-Wall Cracks

Author(s):  
Franck Schoefs ◽  
Mustapha Rguig

The actual challenge for the requalification of existing offshore structures through a rational process of reassessment leads to state the importance of Risk Based Inspection methodology. This paper points out the inspection results modelling and their contribution to decision aid tools. The study of the impact of through cracks on structural integrity of jacket platforms is still a challenge. The detection of large cracks is first addressed. In order to minimize inspections and maintenance costs, all the available data from inspection results, such as probability of detection and probability of false alarm, must be addressed, as well as the probability of crack presence. This can be achieved by the use of the decision theory. These capabilities of Non Destructive Testing give a first input for the risk study. A cost function is suggested to introduce this modelling into a risk analysis and is devoted to help rank the NDT tools. The case of large through-wall cracks is specifically addressed.

2014 ◽  
Vol 70 (3) ◽  
Author(s):  
Nasarudin Ahmad ◽  
Ruzairi Abdul Rahim ◽  
Herlina Abdul Rahim ◽  
Mohd Hafiz Fazlul Rahiman

Although the technique of using ultrasound has reached maturity by given the extent of the development of sensors, but the use of the various areas still can be explore. Many types of ultrasonic sensors are still at conventional in use especially for measurement equipment in the industry. With the advancement of signal processing techniques, high-speed computing, and the latest techniques in image formation based Non-destructive testing (NDT) methods, the usage of ultrasound in concrete NDT testing is very extensive because the technique is very simple and should not damage the concrete structure to be investigated. Many of the parameters need to be tested using ultrasound techniques to concrete can be realized. Starting with the initial process for of concrete mixing until the concrete matured to the age of century old. Various tests are available to test a variety of non-destructive of concrete completely, in which there is no damage to the concrete, through those where the concrete surface is damaged a bit, to partially destructive testing, such as core tests and insertion and pull-off test, which surface to be repaired after the test. Testing parameter features that can be evaluated using non-destructive testing and destructive testing of some rather large and include basic parameters such as density, elastic modulus and strength and surface hardness and surface absorption, and reinforcement location, size and distance from the surface. In some cases it is also possible to check the quality of the workmanship and structural integrity of the ability to detect voids, cracks and delamination. A review of NDT using ultrasound on concrete are presented in this paper to highlight the important aspect to consider when one to consider the application and development of ultrasound testing on concrete by considering ultrasound signal capturing, processing and presenting.


2019 ◽  
Vol 277 ◽  
pp. 03019
Author(s):  
Bo Song ◽  
Jian Li ◽  
Man sheng Wang

The knock detection method is one of the non-destructive testing methods for assembly prefabricated components. The knocker is used to knock on the concrete prefabricated components to be tested. The internal conditions of the tested components can be judged by analyzing the time-domain and frequency-domain diagrams of the knocker. In this paper, the impact of the change of the knock point on the detection is studied by using the knock detection experiment. It is found that the location of the knock point has a great influence on the detection. With the change of the position of the knock point, the peak frequency in the spectrum obtained by the detection changes correspondingly. According to the frequency information corresponding to the peak value in the spectrum, the depth of the void to the knock surface can be calculated.


Sadhana ◽  
1995 ◽  
Vol 20 (1) ◽  
pp. 5-38 ◽  
Author(s):  
Baldev Raj ◽  
T Jayakumar ◽  
B P C Rao

Author(s):  
X. E. Gros

Non-destructive testing (NDT) is a useful tool to assess the structural integrity of components in order to maintain quality and safety standards. A low-cost electromagnetic technique based on eddy currents induced into a material appeared promising for the inspection of composite materials. Experiments were carried out in order to assess the potential of eddy currents in detecting delamination in rubber tyres. Infrared thermography was used to verify inspection results achieved with eddy currents. Non-destructive examination results are presented in this paper; these confirm that eddy current testing is an economically viable alternative for the inspection of steel reinforced truck tyres.


Author(s):  
Romain Ecault ◽  
Ana Reguero Simon ◽  
Célian Cherrier ◽  
Paweł H. Malinowski ◽  
Tomasz Wandowski ◽  
...  

AbstractThis chapter highlights two advances towards a higher maturity of versatile extended non-destructive testing (ENDT) procedures. Full-scale demonstration tests are presented in realistic user application cases that involve typical production or repair scenarios. Subsequently, the investigations used to assess the probability of detection (POD) are detailed for the respective ENDT processes and application-relevant scenarios in a realistic environment. Although some results indicated that some additional in-depth investigations would be even more enlightening, these demonstrations still clearly showed that developments and progress described in the previous chapters have enabled some of the technologies to achieve a maturity that is sufficient to proceed towards industrial implementation. Some ENDT techniques revealed the presence of contaminants on real structural parts with unknown contaminant amounts. For the first time, POD results obtained for ENDT investigations are presented. Some ENDT procedures permitted POD results to be obtained for several scenarios, while others showed technologically relevant POD only for certain scenarios. For two ENDT techniques, determining the POD helped to enhance the respective testing and evaluation procedures. In most of the cases, it was possible to estimate a preliminary quantification of POD by giving the POD90/95. For some techniques, this value was below the lowest contamination degree.


After prolonged usage of materials, the formation of cracks and corrosion initiates due to stress, loading condition, the environment of operation, etc. and this affects the structural integrity of structures. Periodic inspection of structures is usually planned, especially in industries where the impact of failure could be devastating, such as oil and gas pipelines, storage tanks, vessels, and airplanes, etc. which are just a few amongst others. This inspection is often aimed at detecting cracks and corrosion of internal and external components using several forms of non-destructive testing mechanism usually performed by a specialist at a high rate. To reduce the cost of inspection as well as downtime due to inspections and maintenance, deployments of mobile robots with fault tracking and identification purpose are steadily increasing. This paper, therefore, details the implementation of an image processing technique using MATLAB to identify defects of structural elements.


2016 ◽  
Vol 879 ◽  
pp. 1841-1846 ◽  
Author(s):  
Peter Starke ◽  
Hao Ran Wu ◽  
Christian Boller

The comprehensive characterization of the change in metallic materials’ microstructure due to an applied load is of prime importance for the understanding of basic fatigue mechanisms or more general damage evolution processes. If those mechanisms and processes are to be understood to a much greater extent, advanced fatigue life calculation methods being far away from linear damage accumulation models, have to be realized providing more than “classic fatigue data” only. Among others the PHYBAL (physically based fatigue life calculation) method including current enhancements and a thereon-based development named SteBLife (step-bar fatigue life approach) have been developed over the last 10 years. These methods allow the efforts in experimentation to be reduced by more than 90 % and therefore offer the possibility to take further fatigue relevant parameters into account. This therefore allows a variety of S,N-curves dependent on those fatigue relevant parameters to be generated with those methods easily establishing a multidimensional dataset. To just name a few examples of those parameters such as the influence of temperature, loading conditions, geometry as well as thermal and mechanical ageing processes on the fatigue behavior can now be calculated in accordance to a process being straightforward leading to an important step with regard to improving the efficiency of assessing structural components. Consequently, safety factors can be defined more in accordance to structural needs, being of highest interest with respect to the increasing number of ageing infrastructure such as highways, bridges or others. A lot of this ageing infrastructure has a strong need to be managed with respect to its structural integrity and the engineering community therefore tries the residual life of this infrastructure to be determined as appropriate as possible. In that context non-destructive testing parameters are increasingly considered to characterize a metallic material’s microstructure allowing more precise information to be obtained regarding the actual damage condition and the integrity of a component. The paper will address the high capability of non-destructive testing techniques for the evaluation of damage evolution processes also with respect to mechanism based fatigue as well as residual life calculations according to PHYBAL and SteBLife.


Sign in / Sign up

Export Citation Format

Share Document