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Full-Text Articles in Biomedical Engineering and Bioengineering
Recording Of Elevated Temperature Fatigue Crack Growth Data By Dcpd System, N. Ramachandran, N. Arakere, Tarun Goswami
Recording Of Elevated Temperature Fatigue Crack Growth Data By Dcpd System, N. Ramachandran, N. Arakere, Tarun Goswami
Biomedical, Industrial & Human Factors Engineering Faculty Publications
The growth of "long" fatigue cracks, in α-β titanium alloy forging, subjected to cyclic stresses, is studied in this paper. The fatigue crack growth rate (FCGR) data were recorded at room temperature, 350, 450, 550 and 650°F using the Direct Current Potential Difference (DCPD) technique. The DCPD method, used in this investigation, was found to record and correlate the potential difference in terms of crack growth rate (da/dN) and Mode I stress intensity factor range satisfactorily. Various factors related to error minimization and calibration equations for compact tension specimens have been elaborated. Also discussed were the means to enhance the …
Dwell Fatigue I : Damage Mechanisms, Tarun Goswami
Dwell Fatigue I : Damage Mechanisms, Tarun Goswami
Biomedical, Industrial & Human Factors Engineering Faculty Publications
The mechanisms controlling deformation and failure under high temperature creep-fatigue conditions of materials are examined in this paper. The materials studied are solder alloys, copper alloys, low alloy steels, stainless steels, titanium alloys, and Ni-based alloys. The deformation and failure mechanisms were different (fatigue, creep, oxidation and their interactions) depending upon test and material parameters employed. Deformation mechanisms, such as cavity formation, grain boundary damage, intergranular (IG) and transgranular (TG) damage, oxidation, internal damage, dislocation cell concentration, and oxide mechanisms are very important in order to gain more knowledge of fatigue behavior of materials. The observed mechanisms can be categorized …
Applicability Of Modified Diercks Equation With Nrim Data, Tarun Goswami
Applicability Of Modified Diercks Equation With Nrim Data, Tarun Goswami
Biomedical, Industrial & Human Factors Engineering Faculty Publications
The applicability of the modified Diercks equation (MDE) was assessed with elevated temperature low cycle fatigue (ETLCF) data generated by the National Research Institute for Metals (NRIM) for lCr-Mo-V, 1.25Cr-Mo, 2.25Cr-Mo and 9Cr-lMo steels respectively. The modified Diercks equation was assessed with data generated with symmetrical, slow-fast and hold-time waveforms for low alloy steels. The following characteristics were observed: Symmetrical waveforms: Five strain rates were used with these waveforms where predicted life was by a factor of ± x2 for 77%, 87%, 82% and 92% of data points for lCr-Mo-V, 1.25Cr-Mo, 2.25Cr-Mo and 9CrlMo steels respectively. Slow-fast waveforms: Diercks equation …
Creep-Fatigue Life Prediction - A Ductility Model, Tarun Goswami
Creep-Fatigue Life Prediction - A Ductility Model, Tarun Goswami
Biomedical, Industrial & Human Factors Engineering Faculty Publications
Creep-fatigue life prediction methods are briefly reviewed. Phenomenological methods of life prediction are very popular, since they use several test and metallographic parameters in model formulation. They also require numerous test parameters determined from specialized tests. Requirements of phenomenological methods have been summarized. Ductility measurement and modeling aspects have been reviewed. A new model has been developed with the assumption that with increasing fatigue cycles the ductility gradually decreases and the specimen fails as a result of exhaustion of ductility. This has been achieved in terms of dynamic viscosity (product of stress and cycle time), equated with material toughness, which …