Proceedings Article | 13 June 2005
Proc. SPIE. 5856, Optical Measurement Systems for Industrial Inspection IV
KEYWORDS: Interferometry, Analytical research, Moire patterns, Numerical analysis, Finite element methods, Data modeling, Semiconductor lasers, Diffraction gratings, Laser energy, 3D modeling
Current design, analysis and control engineering applications require effective experimental methodologies and tools
for determination of displacement and strain fields as well as material characterization. One of the most important
problem in engineering objects is proper design and quality of joints between elements in the form of welds, glued
and riveted joints and many others. Specificly the fatigue and fracture mechanics problems in joints are difficult
to analyze numerically, therefore they need experimental support. In the paper we present the results of static, dynamic
and fatigue experiments performed by grating (moire) interferometry systems. These full-field optical extensometers
provide information about in-plane displacement field (u,v) and strain fields (εx, εy, γxy) in the region of a joint subjected
to various modes of loads. It is shown that proper design of full-field extensometer (insensitivity to vibration, good
quality of interferogram, automatic analysis of long series of interferograms) allows to use it efficiently directly at
conventional loading machine in workshop environment and for long term fatigue tests.
In the paper we present results of studies of: conventional laser welds (static, fatigue tests), friction stir weld (static tests),
riveted joint (static, fatigue tests). The methodology of determination of local material constants in different zones
of a joint (inc. Poisson ratio, Young’s modulus) is given. The future trends in hybrid experimental-numerical analysis
of joints in conventional and novel material are discussed.
