Material flaws

The main goal of ultrasonic grain noise suppression in material flaw detection is to improve the perceptual possibilities of the operator to observe defect echoes. The suppression is defined as perceptually ideal when a received signal (or image) which contains echoes buried in noise is filtered to yield nonzero values only at the positions of the defect echoes. 

A common known method to get eddy-current informations about material flaws is the measurement of real- and imaginary part of the complex impedance of a coil in absolute circuit. The measurement, shown in this paper, are done with an impedance analyzer (HP4192A). The device measures the serial inductance L, and the serial resistance Rs of the complex impedance with an auto-balance bridge measurement circuit [5]. 

The second signal (Signal 2 = Hat) comes from the measurement of duration of the first period of the oscillation voltage. The period is changing in the near of a material flaw. 

Hanke, R. B5bel, F. Determination of material flaw size by intensity evaluation of polychromatic X-ray transmission. NDT-I-E International, Vol. 25(2), 1992, pp. 87-93. 

Distinctions need to be drawn between simple material flaws and service-threatening defects. Rejection of components that are merely flawed can be economically unjustifiable. Distinguishing between flaws and defects generally requires the judgment of an experienced inspector. 

Detecting Material Flaws Flaws in welded metal parts of airplanes can be identified by placing the isotope iridium-192 on one side of the weld and photographic film on the other side to detect gamma rays that pass through. How does the gamma ray emission affect the atomic number and mass number of the iridium ... 

Zubehor) supplies Materialermudung/ Werkstoffermudung material fatigue Materialfehler defect in material, flaw in material... 

Human error Design errors including incorrect dimensioning, neglected dynamic effects, unrecognised stability problems Construction errors such as material flaws and incorrect assembly... 

Human errors—design error, material flaw, construction error, misuse, lack of maintenance. 

The failure of any engineering structure is cause for concern, for a single incident can indicate a material flaw or design error that renders myriad apparent structural successes irrelevant. In... 

In composite materials, flaws, bonding faults and internal defects have all been examined using liquid crystal thermography, [177-184]. Surface and subsurface flaws have been detected, including regions of unstable plastic flow in aluminum alloys (Lueder lines) [185], faults in welded metals [186], and cracks, voids and leaks in pressure vessels [187-188]. Potential fracture sites have been determined in metals... 

Failure mode I Fractured spring. Its causes are misalignment, corrosion, material flaws, and stress concentration due to tooling marks. 

Most adhesives are polymer-based materials and exhibit viscoelastic behavior. Some adhesives are elastomer materials and also exhibit full or partial rubberlike properties. The word elastic refers to the ability of a material to return to its original dimensions when unloaded, and the term mer refers to the polymeric molecular makeup in the word elastomer. In cases where brittle material behavior prevails, and especially, when inherent material flaws such as cracks, voids, and disbonds exist in such materials, the use of the methods of fracture mechanics are called for. For continuum behavior, however, the use of damage models is considered appropriate in order to be able to model the progression of distributed and non-catastrophic failures and/or irreversible changes in material s microstructure, which are sometimes described as elastic Hmit, yield, plastic flow, stress whitening, and strain hardening. Many adhesive materials are composite materials due to the presence of secondary phases such as fillers and carriers. Consequently, accurate analysis and modeling of such composite adhesives require the use of the methods of composite materials. 

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