• Journal of the Korean Society for Precision Engineering
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• v.3 no.3
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• pp.22-29
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• 1986

In Korea, all the photoelastic materials are imported from foreign countries. The cost of these materials are expensive and problems in importing have been restrained research and development in this field. To reduce these problems, the domestic EPOXY RESIN which is made of bisphenol type epoxy resin have been investigated in this study to find to find a photoelastic characterics by tensile test and to measure photoelastic sensitivity coefficient and transition temperature and the optimum using condition was also investigated.

• Journal of Ocean Engineering and Technology
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• v.4 no.1
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• pp.110-119
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• 1990

This study is concerned about the stress concentration factor measurement by photoelastic method, for the case of two circular holes arrangement in 3mm semi-infinite plate under tensile load, the ratio of those two circular holes diameter, the ratio of distance apart from circular holes to breadth and the two holes arrangement angle with loading direction were varied. Besides, the measured stress concentration by photoelastic method around one circular hole was compared with that by strain-gage method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.11 s.170
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• pp.1904-1911
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• 1999

The most effective material in the shape memory alloy(SMA) is the TiNi alloy, because its shape recovery characteristics are very excellent. We molded the composite material with shape memory function. The fiber of it is $Ti_{50}-Ni_{50}$ shape memory alloy and matrix of it is epoxy resin(Araldite B41, Hardner HT903. Ciba Geigy), its adhesive and optical sensitivity are very excellent. It was assured that the composite material could be used as model material of photoelastic experiment for intelligent materials or structures. In this research, the composite material with shape memory function is used as model material of photoelastic experiment. Photoelastic experimental hybrid method is developed in this research, it is assured that it is useful on the obtaining stress intensity factor and the separation of stress components from only isochromatic data. The measuring method of stress intensity factor of intelligent material by photoelastic experiment is introduced. In the mode I state, we can know that stress intensity factors are decreased more than 50% of stress intensity factor of room temperature when temperature of fiber is greater than 4$0^{\circ}C$, prestrain greater than 5% and fiber volume ratio greater than 0.42% and that stress intensity factors are decreased by 100% when fiber volume ratio is greater than 0.84%, prestrain greater than 5% and temperature greater than 60 $^{\circ}C$.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.2
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• pp.83-89
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• 1994

It is important for an ultrasonic testing to know the sound pressure field and the directivity of ultrasonic waves propagating in a solid. The directivity of ultrasonic wave is closely related to the sensitivity, the scanning pitch, the arrangement of angle probe, and the defect kind in ultrasonic testing. This paper describes on the directivity measurement of ultrasonic wave using ultrasonic wave visualization method. The directivity of the shear wave emitted from the angle probes were constant during propagation. The difference of directivity was existed between 2MHz and 4MHz angle probes. The centers of directivity were located backward from the incident poing and inside of the angle probe and were not changed during the wave propagation.