Electronic speckle pattern interferometry

B. Sharp, Electronic speckle pattern interferometry (ESPI), an engineering approach ,... 

Fig. 20, A is approximately 8 pm for ZnSe but under 0.04 pm for CVD diamond. Recent results have been reported using electronic speckle pattern interferometry (ESPI) [56] using a CO2 laser of power up to I kW on a CVD diamond and a ZnSe windows of 25 mm aperture and AR coated on both sides. The ZnSe window starts to deform at moderately low power levels (50 W). In the CVD diamond window discernible distortions start at powers over 700 W. These...

The mechanism of stress transfer from the plastic matrix to the wood particles and vice versa was investigated by Sretenovic et al. [68]. They measured the strain distribution around the particle using electronic speckle pattern interferometry (ESPI). They also conducted an analytical analysis and finite element modelling of strain and stress distribution in the wood plastic composite. 

Hack E and Broennimann R, Electronic speckle pattern interferometry deformation measurement on lightweight structures under thermal load . Optics Lasers Eng., 1999, 31(3), 213-22. 

The digital phase-stepping technique can also be used with electronic speckle pattern interferometry. Indus case each speckle is treated as an individual interference pattern, the hght from the object having a particular ampli-mde and phase. If the optical path difference at each such point with respect to the reference beam is meastrred by the phase-stepping technique before and after the strrface moves, the change gives a direct measure of the strrface displacement at that point. 

Reinforced thermoplastic matrix pipes may be subjected to different types of loading conditions as well as different environmental conditions. However, they may suffer damage due to unexpected working conditions (low velocity impact, such as stones, tools, etc). This paper describes a methodology based upon fracture mechanics to evaluate possible pipe damages. It reports a set of tests made to characterize materials and pipes. Fracture Mechanics tests were made in samples subjected to low velocity impact. The study of damage evolution was done by using the ESPI (Electronic Speckle Pattern Interferometry) technique in order to determine the delamination area. 

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