List of Awardees and Research Papers
1. Pritee Sharma, Indian Institute of Technology, Mumbai.
6th East West Center International Graduate Student Conference, Honolulu, Hawaii, Feb 15-17, 2007.
2. Ashish K Mishra, Indian Institute of Technology, Kanpur.
Population Association of America Annual Conference, New York, NY, March 29-31, 2007.
3. T.V. Sekhar, International Institute of Population Sciences, Mumbai.
Summer workshop “Communicating with Policy Makers About Population and Health”
East-West Center, Hawaii, May 29- June 28, 2007.
4. Viiay Sarode, Mulund College of Commerce, Mumbai.
Population Association of America Annual Conference, New York, NY, March 29-31, 2007 (Member supported Award).
5. Sarmishtha Palit Sagar, National Metallurgical Laboratory, Jamshedpur.
“Non-linear ultrasonic to assess localized plastic deformation during high cycle fatigue”
Sarmishtha Palit Sagar, Avijit Metya, Narayan Parida, Rabindra Nath Ghosh
National Metallurgical Laboratory, Materials Science & Technology Division,
Jamshedpur, Jharkhand, India
Non-linear ultrasonic (NLU) is coming up as a potential non-destructive technique for materials damage and degradation study especially for fatigue damage assessment. When a purely sinusoidal acoustic wave propagates through a degraded material, it distorts and generates harmonics of the fundamental waveform because of the nonlinearity of the propagation medium. A quantitative measure of the wave distortion is the ‘acoustic’ nonlinearity parameter. This nonlinearity parameter is proportional to the ratio of the amplitude of the 2nd harmonic to the square of the amplitude of the fundamental of the transmitted ultrasonic signal. In the present work our aim is to apply the NLU to detect the location of maximum localized plastic deformation occurred during fatigue which could be useful for fatigue damage assessment of industrial components to avoid catastrophic failure. We have chosen polycrystalline copper for high cycle fatigue (HCF) study as the microstructure of the polycrystalline copper has been well established during fatigue. In this work we have applied both conventional ultrasonic and NLU techniques to evaluate the fatigue hardening and softening in polycrystalline copper during HCF. For conventional ultrasonic, longitudinal velocity and attenuation coefficients have been determined. It has been observed that the position of maximum localized plastic deformation can not be detected by longitudinal velocity and attenuation coefficients, where as the NLU parameter detects the same at the stage of only 30% of damage corresponds to the total fatigue life of the material. The result of NLU has also been correlated with the hardness during fatigue. This work reveals the potential of NLU to assess the localized plastic deformation during high cycle fatigue much earlier to the failure.”
34th Annual Review of Progress in Quantitative Nondestructive Evaluation, July 22-July 27, 2007 at Colorado School of Mines, Golden, Colorado.