Home Bio-sketch
Research Teaching Books
& Publications Patents Grants and Contracts Laboratories Students & Scholars LinksProfessor Yang joined Oakland University in October. His research interests and competencies lie in the areas of modern optical measuring techniques and their applications in Automobile, Aerospace and High-Tech industries, with a focus on digital, automatic, quantitative 3D and whole field measurement of contour, deformation/displacement, strain/stress, vibration, mechanical properties and so on.
Because of his significant contributions and specific achievements in optical metrology and nondestructive testing, Dr. Yang was awarded the Fellow of SPIE - The International Society of Optics and Phonics in 2008. At the moment, 7 PhD students and a number of Master students are pursuing their PhD and Master degrees in Dr. Yang's group.
The first version of SHEARWIN software from laboratory of Photoelasticity, Holography and Shearography, University of Kassel, Germany, - a user guided software which has been used in the industries for automatic, quantitative measurement of digital holography and digital shearography, was developed under Dr. Yang's guidance, while he was working in University of Kassel from 1991 to 1998. Also Dr. Yang developed portable digital shearographic sensors for Non-destructive testing (NDT), strain/stress measurement and vibration analysis during that time. Because of his outstanding achievements in these areas, Dr. Yang received "Der erste Preis der VDI Nordhessen in 1998" (1st prize of the Association of German Engineers in 1998 for the best work in the field of technology/science in the North Hessen province.).(VDI-Preis)
During his work at Ettemeyer AG, Germany, Dr. Yang developed and improved as project leader with his team a novel 3D-DSPI (Digital Speckle Pattern Interferomertry) sensor: MicroStar, in which a contour and deformation measurement using DSPI was integrated first time into a single sensor, thus, the statement that DSPI can measure strain/stress only on objects with a plane surface has become history. MicroStar has received a wide acceptance in automobile and aerospace industries.
As an R&D scientist at JDS-uniphase, Ottawa, Canada, - the leading company of optical components in telecommunication, Dr. Yang built Holography laboratory there and developed an universal holographic microscope for measuring contour, deformation/displacement etc. of microelements like MEMS (MicroElectroMechanical Systems).
His current research interests cover following areas:
This research is based on the very sensitive DSPI (also called TV-holography) technique that is able to deliver fast, complete three-dimensional information about the component behavior at thousands of measuring points in the field of view. The research has been focusing on whole field determination of strain/stress on 3D object, on a complicated or an indirectly observable surface (e.g. inner surface of a container). The techniques like DSPI for contour measurement, for 3D deformation, strain/stress measurement and new concepts based on optical fiber or Endoscope technique etc. have been or will be the research topics.
A user-guided software to perform automatic and quantitative measurement is a basic concept to transfer new optical measuring techniques into industries. The research in this areas covers developments both in hardware to perform automatically measurement and in software using C++ language to evaluate quantitatively any interferograms, e.g. by using phase shift technique.
The demand to reduce the overall noise level on any machine requires detailed knowledge about the vibration behavior of the different components. Using traditional point measuring techniques like vibrometers, the analysis of machine vibrations is especially laborious, because the large areas require many measuring points. Holography or DSPI is a non-contact measuring technique and provides full field information that is a big advantage in comparison to the traditional techniques. The research in this area has been focusing on non-contact, whole field vibration analysis using DSPI on any objects with a harmonic or transient exciting, for determination of nature frequencies, vibration amplitude, and vibration phase as well as experimental determination of damping coefficient etc.
In recent years, the use of composite material in the automobile and aerospace industries has become increasingly widespread. Thus effective techniques for non-destructive testing (NDT), especially for on-line inspection of the composite materials, have become more and more important. Various inspection methods such as holography, shearography, moire technique, ultrasonic, acoustical emissions etc. have been applied for NDT of the composite materials in recent years. Among these methods, shearography appears to be more practical. It is simple in optical set-up due to its "self-referencing" system and insensitive against rigid-body motions. It measures directly the strain information and obtains thus directly the information of strain concentration in the defect positions. Prof. Yang is working closely (in same laboratory) with Prof. Y.Y. Hung - the inventor of shearography. The research in this area is to expand the further applications in industries using digital shearography.
MicroElectroMechanicalSystems (MEMS) are devices fabricated via techniques such as micro photolithographyto create miniature actuators and sensors and are being applied increasingly in automobile, aerospace and high-Tech industries. The objective of the proposed research is to develop a digital microinterferometer to measure 3D-displacements of MEMS and microelements. This new technique will allow measuring MEMS down to 30 microns in size, which corresponds to the smallest parts of most current MEMS. The measured results will be evaluated quantitatively and automatically and thus, a strain/stress analysis will be possible. Furthermore, the spatial resolution, the displacement sensitivity and the measurement accuracy of this technique will be discussed. The outcome of the project, therefore, will impact significantly on the fast growing industries of miniaturization and on emerging research areas in MEMS and microelements.
Besides above areas, Prof. Yang's research interests cover also laser triangulation, moire technique, projected and reflected fringe techniques, design validation and optimization as well as design of Instrumentation etc.