Nondestructive evaluation of aircraft composites using reflective terahertz time domain spectroscopy

Stoik, Christopher D.; Bohn, Manfred A.; Blackshire, James L.

doi:10.1016/j.ndteint.2009.09.005

Cited by 115 publications

(57 citation statements)

References 14 publications

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“…Such materials also include multilayer composite materials, which are opaque for visible and infrared light. Moreover, the analysis using THz radiation allows to determine thicknesses of internal layers and to define hidden defects and non-uniformities inside those materials [1][2][3]. It is worth noticing that THz radiation provides a non-destructive, non-ionizing, and contactless method for material evaluation.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, materials exhibiting much better properties for the examination in the THz range are glass fiber-reinforced composites. These and many other materials are being investigated with THz radiation even though there are still problems with the transmission through the material and in addition with scattering in the internal structure [3,10].…”

Section: Introductionmentioning

confidence: 99%

“…Up to now, the UHMWPE composites have not been intensely studied in the THz range [12,13]. The non-destructive evaluation of composite materials [1][2][3][14][15][16] was mostly carried out by the use of THz time-domain spectroscopy (TDS). Nevertheless, there are many other techniques based, for example, on FMCW radar [17], CW imaging using quantum cascade lasers [18], a gas laser [9], or a Gunn diode [19].…”

Section: Introductionmentioning

confidence: 99%

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Precise Determination of Thicknesses of Multilayer Polyethylene Composite Materials by Terahertz Time-Domain Spectroscopy

Pałka

Krimi

Ospald

et al. 2015

J Infrared Milli Terahz Waves

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The multilayer structure of an ultra-high molecular weight polyethylene (UHMWPE) composite material was investigated in the terahertz (THz) spectral range by means of time-domain spectroscopy (TDS) technique. Such structures consist of many alternating layers of fibers, each being perpendicular to the other and each having a thickness of about 50 μm. Refractive indices of two composite samples and of a sample composed of four single layers (plies) having the same fiber orientation were determined for two orthogonal orientations of the electric field in a transmission TDS system. The birefringence of a single layer was measured, and the origin of this phenomenon is discussed. Using the TDS system in reflection, the formation of many pulses shifted in time was observed originating from reflections from interfaces of successive layers caused by the periodic modulation of the refractive index along the propagation of the THz radiation. This phenomenon is theoretically described and simulated by means of a transfer matrix method (TMM). A time-domain fitting procedure was used to determine thicknesses of all layers of the composite material. The reconstructed waveform based on the optimized thicknesses shows very good agreement with the measured waveform, with typical differences between measurements and simulations J Infrared Milli Terahz Waves (2015) between 3 and 7 μm (depending on the sample). As a result, we were able to determine the thicknesses of all layers of two multilayer (~200 plies) structures by means of the reflection TDS technology with high accuracy.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Precise Determination of Thicknesses of Multilayer Polyethylene Composite Materials by Terahertz Time-Domain Spectroscopy

Pałka

Krimi

Ospald

et al. 2015

J Infrared Milli Terahz Waves

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“…Despite many advantages over conventional materials, composites may have defects such as voids, delaminations, matrix and fibers cracks, punctures, mechanical damages or heat damages (Stoik et al 2010). All these imperfections are associated with the production processes and degradation, which result from their maintenance in harsh and demanding environments.…”

mentioning

confidence: 99%

“…Carbon fiber composites reflect very well the THz radiation and almost nothing penetrates to their internal structure (Redo-Sanchez et al 2006). However, glass fiber reinforced composites, for which numerous examinations are carried out due to their universality of applications (Stoik et al 2010;Rutz et al 2006) have better parameters for the examination in the THz range, despite the problems with transmission and scattering of the radiation.…”

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confidence: 99%

Detailed non-destructive evaluation of UHMWPE composites in the terahertz range

Pałka

Miedzińska

2013

Opt Quant Electron

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We report on the terahertz analysis of an internal structure of an ultra-high molecular weight polyethylene (UHMWPE) composite material, which is based on the HB10-tape from Dyneema . This type of composite is very hard and resistant and therefore it is often used to manufacture personal armors such as bulletproof vests and helmets. The multilayer structure of the UHMWPE composite was investigated by means of a raster scanning time domain spectroscopy technique in a reflection configuration. The mechanism of the formation of many shifted in time THz pulses (reflected from the internal layers of the sample) originates from the periodic modulation of the refractive index along the propagation of the radiation. This modulation is connected with alternate layers of fibers, each having different direction (perpendicular to each other). As a result we obtained the detailed three dimensional profile of the 3.3-mm thick sample with all 74 layers clearly visible. Thicknesses of all layers, having around 45 µm each, were determined. Moreover, it is also possible to identify internal defects i.e. delaminations in the internal structure of this composite material.

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Nondestructive Testing of Polymers and Polymer–Matrix Composites

Brunner

Hack

Neuenschwander

2015

Encyclopedia of Polymer Science and Technology

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Because of their unique properties, polymers and polymer–matrix composites pose both challenges and opportunities for nondestructive testing. The increasing use of these materials creates a demand for nondestructive verification of various properties or specifications, determination of structural integrity, or prediction of service‐life. On the other hand, development of new nondestructive test methods, improved sensitivity, or faster data acquisition and analysis may allow for nondestructive testing applications that hitherto did not seem feasible or economical. This article provides a brief overview of established methods and emerging applications in nondestructive testing of polymers and polymer–matrix composites.

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Nondestructive evaluation of aircraft composites using reflective terahertz time domain spectroscopy

Cited by 115 publications

References 14 publications

Precise Determination of Thicknesses of Multilayer Polyethylene Composite Materials by Terahertz Time-Domain Spectroscopy

Precise Determination of Thicknesses of Multilayer Polyethylene Composite Materials by Terahertz Time-Domain Spectroscopy

Detailed non-destructive evaluation of UHMWPE composites in the terahertz range

Nondestructive Testing of Polymers and Polymer–Matrix Composites

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