Jong-Jae Lee, Jong-Woong Park, Young-Soo Park, Hyung-Jo Jung

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.3, pp. 92-92, 2009, DOI:10.3970/icces.2009.012.092

Abstract Measuring the displacement of a flexible bridge is difficult particularly on a long span bridge. In this study, real-time displacement measurement of a long span bridge was carried out using digital image processing techniques which require a target recognition algorithm, projection of the captured image, and calculation of the actual displacement using target geometry and the number of pixels moved. To measure the displacement of a bridge from a distant location which can be regarded as a fixed reference point, a novel image processing method has been devised. By measuring the same target with two independent cameras placed in a… More >

A.K Lazopoulos¹, K.A. Lazopoulos¹, G. Palassopoulos²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.3, pp. 89-91, 2009, DOI:10.3970/icces.2009.012.089

Abstract Simple models for the upper faryngeal obstruction, describing the sleep apnea syndrome are proposed. Stability is discussed, of two and three individualized elements, with and without elastic connections, interacting with the steady flow. Considering the flow as the controlling parameter, critical steady state flows are located and their post-critical behavior is discussed for various models. It is pointed out that the non-linear constitutive elastic laws are necessary contrary to the linear ones introduced by Fodil [1998]. Finally the three element model will be presented and studied with non-linear constitutive relations and side connections. Applications of the theory will be performed… More >

Jan D. Achenbach¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.3, pp. 87-88, 2009, DOI:10.3970/icces.2009.012.087

Abstract A significant limitation of NDE became apparent in the sixties with the advent of fracture mechanics as a major consideration for the determination of structural safety. Fracture mechanics requires quantitative information that has to be obtained from non-destructive testing procedures. The 1970's mark the start of research and development to achieve quantitative capability, and adding the Q to NDE. Since that time significant advances have been made of the methods of quantitative non-destructive evaluation that are the basis of the diagnostics part of structural health management, including sensor development, new techniques such as laser-based ultrasonics, acoustic and x-ray imaging, thermal… More >

Christina Völlmecke¹, M. Ahmer Wadee²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.3, pp. 85-86, 2009, DOI:10.3970/icces.2009.012.085

Abstract A geometrically nonlinear plate model has been developed analytically in order to investigate the buckling behaviour of laminated composite panels containing a centrally located delaminated patch. The panels examined are rectangular and under uniaxial compression. Trigonometric out-of-plane displacement functions are employed in the Rayleigh--Ritz procedure where minimum energy principles are applied to solve for the mechanical behaviour of the plates. The in-plane deformations are determined via von K\'arm\'an's compatibility equation by applying restrained edges at the boundary of the delaminated region. Different delamination configurations are investigated with the critical buckling loads and eigenvectors being determined using linear analysis and the… More >

Weiming Tao¹, Xingwang Yang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.3, pp. 83-84, 2009, DOI:10.3970/icces.2009.012.083

Abstract Laser controlled separation of brittle materials like glass is a promising non-conven\discretionary {-}{}{}tional cutting method. It is an application of the crack propagation driven by thermal stresses induced by laser irradiation. In order to induce and control a crack propagating accurately along predetermined asymmetric trajectory in a brittle plate, an iterative method for effective laser scanning path was presented, and the effect of control parameters on the convergence was investigated. The iterative formulation for laser scanning path was based on PID control theory, which was composed of deviation of the crack from predetermined trajectory and its integral and differential. To… More >

C.M. Lan¹, H. Li¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.3, pp. 75-82, 2009, DOI:10.3970/icces.2009.012.075

Abstract Stay cables are some of the most critical structural components of a bridge. However, stay cables readily suffer from corrosion damage and stress corrosion damage. Thus, health monitoring of stay cables is important for ensuring the integrity and safety of a bridge. Glass Fibre Reinforced Polymer Optical Fibre Bragg Grating (GFRP-OFBG) cable, a kind of fibre Bragg grating optical sensing technology-based smart stay cables, is proposed in this study. The fabrication procedure of the smart stay cable was developed and the self-sensing property of the smart stay cable was calibrated. The application of the smart stay cables on the Tianjin… 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 >

Deyi Zhang¹, Yuequan Bao, Feng Zhou, Hui Li

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.2, pp. 65-72, 2009, DOI:10.3970/icces.2009.012.065

Abstract Modal identification is essential in structural health monitoring (SHM) because that the modal parameters are often used for model updating and damage detection. However, in practical situations, the variation of environmental conditions (e.g. temperature, temperature gradients, humidity, etc.) will impede the reliability of modal identification. In this paper, firstly, the relation of frequency change and variation of environment temperature of space structure is investigated. Then, a structural state assessment method by combing autoregressive moving average (ARMA) and PCA is proposed. The acceleration data from China National Aquatics Center is employed as an example. The results show that variation of frequencies… More >

Yong Huang¹, Hui Li¹, Jinping Ou^1,2

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.2, pp. 53-64, 2009, DOI:10.3970/icces.2009.012.053

Abstract A new damage identification method based on Fractal theory and wavelet packet transform is presented in the paper. The damage identification method utilize frequency-based domain message, time-based domain message and space based domain message effectively. NeXT method were first employed to reduce loading effect of random vibration measured from structures and then the vibration sinal were decomposed into the certain level wavelet packet components. For every time array of wavelet packet component then need to calculate the mean FD values as the ultimated FD values to reduce noise effect. The location of damage in the beam can be determined by… More >

Min Ki Kim¹, Seung Jo Kim²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.2, pp. 52-52, 2009, DOI:10.3970/icces.2009.012.052

Abstract A new concept of hybrid iterative-multifrontal linear solution method is presented for large scale structural analysis problems. Multifrontal solution method is the best direct solution method ever known, so it is adequate for Domain decompostion types of iterative solvers. Multifrontal solver is served as an internal subdomain solver for domain decomposition iterative solver for achieving high performance of domain decomposition iterative solver. Lagrange multiplier is introduced to enforce the continuity of interface between subdomains. And corner DOF is introduced to avoid singularities of subdomains. Hybrid solution method is expected to show good parallel performance for extremely large size structural analysis. More >