&lt;title&gt;Feasibility of optical interference-based NDE methods to inspect helicopter rotor blades&lt;/title&gt;

Findeis, D.; Gryzagoridis, J.

doi:10.1117/12.385035

Cited by 4 publications

(4 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are numbers of failure types which may appear in composites relating both to manufacturing and operating stages. The typical failures, which affect structural integrity and residual strength of the composites, include debonding, delaminating, foreign object inclusions and a kind of damage called as Barely Visible Impact Damage [5][6][7].…”

Section: Specimensmentioning

confidence: 99%

IR Thermography Nondestructive Testing Methods of Composite Materials Used in Aerospace Applications

Świderski¹

2015

Proceedings of the 2015 Asia International Conference on Quantitative InfraRed Thermography

View full text Add to dashboard Cite

In case of composite materials we have to deal with the presence of both high mechanical resistance parameters and low specific gravity. Hence in recent years their use rapidly grows in structures for which these characteristics are of paramount importance. There are mainly aerospace structures. Typical defects of composite materials are: delaminating, lack of adhesion, cracks, concentrations and deformations. These defects can come into being both in manufacturing processes and during exploitation. With the development of technology for producing composite materials the requirements are growing for assessment of their quality. For this purpose nondestructive testing (NDT) is used. NDT procedures using IR thermography can be divided into passive and active. For the diagnosis of defects in composite materials of aerospace applications the active IR thermography methods are used in many cases. The paper presents examples of selected results of defects detection and description of used methods.

show abstract

Section: Specimensmentioning

confidence: 99%

IR Thermography Nondestructive Testing Methods of Composite Materials Used in Aerospace Applications

Świderski¹

2015

Proceedings of the 2015 Asia International Conference on Quantitative InfraRed Thermography

View full text Add to dashboard Cite

show abstract

“…This section contains samples of some of the work undertaken in the past using ESPI as a non destructive testing technique. ( Findeis and Gryzagoridis (2), (3), (4), (5), (6) ). The purpose is an attempt to show the versatility of the technique, as a simple diagnostic or flaw identifying tool used in the testing of a variety of engineering components made from various materials.…”

Section: Defect Detectionmentioning

confidence: 99%

Residual stress determination and defect detection using electronic speckle pattern interferometry

Gryzagoridis¹,

Findeis²,

Tait³

2005

insight

View full text Add to dashboard Cite

The paper deals with the methodology of determining residual stresses using Electronic Speckle Pattern Interferometry (ESPI). ESPI can be used as a truly non-destructive testing technique in that it is a laser based, optical, full field, non contacting method which reveals surface displacements to an accuracy of approximately 300 nanometres when a Helium Neon laser is used. In a simple experiment, a fixed-ends rectangular aluminium plate was subjected to uniform loading and the out of plane surface displacement field was obtained through ESPI. Subsequently a comparison of these measurements was made with measurements obtained after the plate was subjected to shot peening. The above method aimed to identify the extent of residual stresses that were imposed on the rectangular plate after the shot peening process which is known to induce such stress. Bearing in mind that ESPI produces a full field surface displacement map through a characteristic interference fringe pattern, any anomaly displayed on the fringe pattern could be interpreted as a flaw or defect on or beneath the surface under observation. The authors have included in this paper typical examples where the ESPI applied in a prototype device constructed by the authors, has identified defects in various engineering components made from a variety of materials.

show abstract

“…Over the last 10 years these two techniques have enjoyed much research in the Department of Mechanical Engineering at the University of Cape Town, and the application of these optical interference techniques and their ability to detect the above-mentioned flaws have been published in numerous papers 2,3 . Both techniques have the ability to detect the displacement of an object in response to an applied stress.…”

Section: Introductionmentioning

confidence: 99%

<title>Vibration isolation techniques suitable for portable electronic speckle pattern interferometry</title>

2002

Self Cite

View full text Add to dashboard Cite

Electronic Speckle Pattern Interferometry (ESPI) and Digital Shearography are optical interference techniques, suitable for non-destructive inspection procedures. Due to the stringent vibration isolation conditions required for ESPI, the technique is mainly suited for laboratory based inspection procedures, which cannot be said for Digital Shearography. On the other hand, the interference patterns obtained using ESPI exhibit better fringe definition and contrast than those obtained using Digital Shearography. The image quality of Digital Shearography can be improved by introducing phase stepping and unwrapping techniques, but these methods add a level of complexity to the inspection system and reduce the image refresh rate of the overall process.As part of a project to produce a low cost portable ESPI system suitable for industrial applications, this paper investigates various methods of minimizing the impact of environmental vibration on the ESPI technique. This can be achieved by effectively 'freezing' the object movement during the image acquisition process. The methods employed include using a high-powered infra-red laser, which is continuously pulsed using an electronic signal generator as well as a mechanical chopper. The effect of using a variable shutter speed camera in conjunction with custom written software acquisition routines is also studied.The techniques employed are described and are applied to selected samples. The initial results are presented and analysed. Conclusions are drawn and their impact on the feasibility of a portable ESPI system discussed.

show abstract

<title>Feasibility of optical interference-based NDE methods to inspect helicopter rotor blades</title>

Cited by 4 publications

References 2 publications

IR Thermography Nondestructive Testing Methods of Composite Materials Used in Aerospace Applications

IR Thermography Nondestructive Testing Methods of Composite Materials Used in Aerospace Applications

Residual stress determination and defect detection using electronic speckle pattern interferometry

<title>Vibration isolation techniques suitable for portable electronic speckle pattern interferometry</title>

Contact Info

Product

Resources

About