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Full-Text Articles in Engineering
Waveform-Based Selection Of Acoustic Emission Events Generated By Damage In Composite Materials, Emmanuel Maillet, Gregory Morscher
Waveform-Based Selection Of Acoustic Emission Events Generated By Damage In Composite Materials, Emmanuel Maillet, Gregory Morscher
Dr. Gregory N. Morscher
Acoustic emission (AE) has been shown to be a promising health monitoring technique for composite materials as it allows real-time location and identification of damage. When attempting to relate the recorded acoustic emission to a material׳s mechanical behavior, the relevance of results relies on an accurate selection of AE originating from material damage. Indeed, during mechanical tests most of the recorded AE is generated outside of the volume of interest and without proper filtering these AE signals can significantly affect the analysis. To date, there exists no common procedure for the selection of AE signals and therefore results can hardly …
Short Crack Growth Model In A Particulate Composite Using Nonlinear Elastic Fracture Mechanics, Ying Zhang, Tsuchin Chu, Ajay Mahajan
Short Crack Growth Model In A Particulate Composite Using Nonlinear Elastic Fracture Mechanics, Ying Zhang, Tsuchin Chu, Ajay Mahajan
Dr. Ajay Mahajan
The fracture mechanics model for a long crack does not work very well with short-crack propagation when the initial crack length is less than 5.1 mm (0.2 inch). In order to investigate the short crack effect, a series of tests of particulate composite specimens with long and short cracks were performed and the results recorded on a video tape. This test data was analyzed to determine the fracture parameters. Two initial crack lengths, 2.5 mm (0.1 inches) and 7.6 mm (0.3 inches) were used in the crack propagation tests. Based on the principle of linear elastic fracture mechanics (LEFM), the …
Determination Of Optimal Experimental Parameters For Transient Thermography Imaging Using Finite-Element Models, Tsuchin Chu, Ajay Mahajan, A. Digrgorio, S. Russell
Determination Of Optimal Experimental Parameters For Transient Thermography Imaging Using Finite-Element Models, Tsuchin Chu, Ajay Mahajan, A. Digrgorio, S. Russell
Dr. Ajay Mahajan
A study was conducted to determine the optimal inspection parameters such as range and time for finding defects in carbon/epoxy composite panels using IR thermography imaging. The present paper presents an innovative method for automatically selecting these parameters for evaluating composites based on a series of finite-element models. Such finite-element models of composite panels with flaws at different depth locations were constructed a priori and analysed to estimate the optimal operating parameters. The optimal inspection range and time were identified in the contour plots obtained from the appropriate finite-element analysis results. A graphite–epoxy composite panel with phantom defects at various …
In Situ Infrared Study Of The Role Of Peg In Stabilizing Silica-Supported Amines For Co2 Capture, Jak Tanthana, Steven Chuang
In Situ Infrared Study Of The Role Of Peg In Stabilizing Silica-Supported Amines For Co2 Capture, Jak Tanthana, Steven Chuang
Steven S.C. Chuang
The CO(2) capture capacity, adsorption mechanism, and degradation characteristics of two sorbents, silica-supported tetraethylenepentamine (TEPA/SiO(2)) and polyethylene-glycol-modified TEPA/SiO(2) (PEG/TEPA/SiO(2)), are studied by diffuse reflectance infrared Fourier transform spectroscopy and mass spectrometry. The CO(2) capture capacities of TEPA/SiO(2) and PEG/TEPA/SiO(2) are determined to be 2087 and 1110 micromol CO(2) g(-1) sorbent, respectively. Both sorbents adsorb CO(2) as hydrogen-bonding species, NH(2)--O, and carbamate/carboxylate species. The CO(2) adsorption half-time increases with the number of CO(2) capture cycles. Infrared results suggest that the increased adsorption half-time is a result of diffusion limitation, caused by accumulation of TEPA and PEG species on the surface of …