Helen Hongniao Chen¹, Ray Kai Leung Su¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.15, No.3, pp. 91-102, 2010, DOI:10.3970/icces.2010.015.091

Abstract In this study, Electronic Speckle Pattern Interferometry (ESPI) technique was used to measure the surface displacement and strain fields around cracks in concrete beams. ESPI has high accuracy and can determine full-field deformations of concrete. However, tiny rigid-body movements of beam specimens can spoil the ESPI measurement and cause virtual deformations and false strains. Based on the theory of geometrical optics, this paper proposes a method to eliminate the false strains caused by rigid-body motion. The correction procedure was validated experimentally. Furthermore, the crack evolution in a pre-notched beam is presented. The critical minimum crack width of a microcrack is… More >

Hsien-Chie Cheng¹, Yu-Chen Hsu², Wen-Hwa Chen²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.2, pp. 73-74, 2009, DOI:10.3970/icces.2009.012.073

Abstract Due to the limitation of fabrication technologies nowadays, initial defects in carbon nanotubes (CNTs) are inevitably perceived particularly during the manufacturing process or chemical treatment. The investigation of the effects of initial defects existing in CNTs on their mechanical properties and fracture behaviors becomes essential for their potentiality in engineering applications.
In this study, the defect effects, including number in percentage, type, and location, are explored using the molecular dynamics (MD) simulation with Tersoff Brenner potential. Results show that the mechanical properties, such as the elastic modulus, failure strength and strain, are strongly affected by the defects. Moreover, the distribution… More >

Hsien-Chie Cheng¹, Yu-Chen Hsu², Wen-Hwa Chen²

CMC-Computers, Materials & Continua, Vol.11, No.2, pp. 127-146, 2009, DOI:10.3970/cmc.2009.011.127

Abstract Due to the limitation of fabrication technologies nowadays, structural or atomistic defects are often perceived in carbon nanotubes (CNTs) during the manufacturing process. The main goal of the study aims at providing a systematic investigation of the effects of atomistic defects on the nanomechanical properties and fracture behaviors of single-walled CNTs (SWCNTs) using molecular dynamics (MD) simulation. Furthermore, the correlation between local stress distribution and fracture evolution is studied. Key parameters and factors under investigation include the number, type (namely the vacancy and Stone-Wales defects), location and distribution of defects. Results show that the nanomechanical properties of the CNTs, such… More >