Crack detection is one of the important tasks for industrial materials and products from the standpoint of safety. The assessment of the crack geometry would be a crucial parameter for quality control of products. The crack width and length could be rather easily identified by inspecting the actual surface picture. However, the depth of small crack would be difficult to estimate non-destructive...

The experimental determination of fracture mechanical properties of interface cracks is a substantial task for the design for reliability of electronic packages. As interface cracks are dominated by a mode mix between tension and shear mode (crack driving modes I and II) a mixed mode bending method was developed to adjust the ratio of the two modes (mode mixity). For a correct extraction of an ...

OBJECTIVE Epidemiological studies present oral crack use as a potential independent risk factor for hepatitis C virus (HCV) status, yet actual HCV transmission pathways via crack use have not been evidenced. To this end, this exploratory study sought to detect HCV on crack-use paraphernalia used by street crack users. METHODS Crack-use paraphernalia within 60 min of use was collected from 51 ...

In this paper the conjugate gradient (CG) method is employed for identifying the parameters of crack in a functionally graded beam from natural frequency measurement. The crack is modeled as a massless rotational spring with sectional flexibility. By using the Euler-Bernoulli beam theory on two separate beams respectively and applying the compatibility requirements of the crack, the characteris...

In this paper a new approach is taken to identify a crack in a simply supported plate undergoing free vibration. The approach uses a Markov-Chain MonteCarlo implementation of Bayes’ Rule to identify the presence of a crack and, more importantly, to estimate crack parameters; the process also provides confidence intervals for those parameters. To generate the required time series, a semi-analyti...

A basic assumption often made in risk/reliability based inspection planning is that a Bayesian approach can be used. This implies that probabilities of failure can be updated in a consistent way when new information (from inspections and repairs) becomes available. The Bayesian approach and a no-crack detection assumption implies that the inspection time intervals usually become longer and long...

Gearbox maintenance is not an easy task and conventional diagnostic techniques do not always provide suitable indication about failures. In this paper, tooth crack failures have been experimentally investigated. The mechanical system is composed of a two-stage gearbox with spur gears. Two depths of gear cracks are treated. Cyclostationnarity analysis of order 2 has been conducted to some experi...

The optimal material processing in steel industry is difficult because of the multi-constituent and multiphase character of the commercial steels, variety of the possible processing paths, and plant specific equipment characteristics. This paper shows implementation of the genetic programming approach for crack presence modeling after rolling. The data (110 samples covering 7 different steel gr...

Increased traffic speeds and axle loads on modern railways enhance rail track degradation. To eliminate track failure due to rail defects, a condition monitoring system requires methods for the early detection of defects which grow in service. Acoustic emission (AE) monitoring is the only non-destructive technique which might be applied online to study the defect growth under traffic loading. H...