The Problem: To Measure Static Deformations

The K100/HOL optical head using the HoloFringe300 interferometry program allows identification in real-time of the deformations of a test structure subject to a static load. The deformations show up as cosine fringes. These fringes appear as dark bands on the object that connects points of common deformation. The system can also display phase-image fringes. These fringes are the wrapped phase of the cosine fringe function, and relate directly to the object deformation. A robust phase-unwrap program converts the wrapped phase fringes to numerical data for comparison with finite element analyses models.

2a	2b
2c	2d

Figure 2. Deformation Analysis of a Wine Goblet. Fig. 2a shows the real-time fringes of the goblet's deformation due to a rod placed inside it and leaning on the rim. Fig. 2b shows the same deformation displayed in real-time as wrapped phase fringes. Note the fringes have an asymmetrical saw-tooth form. Fig. 2c shows the unwrapped phase fringes, or fringe locus function. Fig. 2d shows the goblet deformation as a 3D plot. (Full-size images)