Gouravaraju Saipraneeth¹, Ranjan Ganguli²

Structural Durability & Health Monitoring, Vol.7, No.1&2, pp. 23-64, 2011, DOI:10.3970/sdhm.2011.007.023

Abstract In this paper, the effect of damage on mode shape related parameters of a beam is investigated. The damage is represented by a localized reduction in beam stiffness. The damage location and amount is varied using a finite element model of the beam to obtain the mode shapes. A beam which is simply supported at both ends is used for the numerical results. The periodic nature of the beam is exploited to obtain spatial Fourier coefficients of the mode shapes. As the damage location and size are varied, it is found that the Fourier coefficients More >

P.C. Chen^∗,†, C.W. Colwell^†, D.D. D’Lima^†,‡

Molecular & Cellular Biomechanics, Vol.8, No.2, pp. 135-148, 2011, DOI:10.3970/mcb.2011.008.135

Abstract A nonlinear viscoelastic finite element model of ultra-high molecular weight polyethylene (UHMWPE) was developed in this study. Eight cylindrical specimens were machined from ram extruded UHMWPE bar stock (GUR 1020) and tested under constant compression at 7% strain for 100 sec. The stress strain data during the initial ramp up to 7% strain was utilized to model the "instantaneous" stress-strain response using a Mooney-Rivlin material model. The viscoelastic behavior was modeled using the time-dependent relaxation in stress seen after the initial maximum stress was achieved using a stored energy formulation. A cylindrical model of similar… More >

Jiawei Xiang¹, Toshiro Matsumoto², Yanxue Wang³, Zhansi Jiang⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.81, No.3&4, pp. 269-294, 2011, DOI:10.3970/cmes.2011.081.269

Abstract Damages occurred in a structure will lead to changes in modal parameters (natural frequencies and modal shapes). The relationship between modal parameters and damage parameters (locations and depths) is very complicated. Single detection method using natural frequencies or modal shapes can not obtain robust damage detection results from the inevitably noise-contaminated modal parameters. To eliminate the complexity, a hybrid approach using both of wavelets on the interval (interval wavelets) method and wavelet finite element model-based method is proposed to detect damage locations and depths. To avoid the boundary distortion phenomenon, Interval wavelets are employed to… More >

B.Cheng¹, R.K.L. Su¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.15, No.3, pp. 75-84, 2010, DOI:10.3970/icces.2010.015.075

Abstract Deep reinforced concrete (RC) coupling beams with low shear span ratios and conventionally reinforced shear stirrups tend to fail in a brittle way with limited ductility and deformability under reversed cyclic loading. Experimental studies have shown that bolting restrained steel plate (BRSP) to existing deep RC coupling beams can enhance the deformability and energy dissipation while maintaining the flexural stiffness, improving the beams' performance during an earthquake. In this study, a nonlinear finite element package ATENA was used to simulate the overall behavior of three previously tested BRSP retrofitted coupling beams. This paper presents the More >

X.-H. Chen¹, Y.-W. Mai²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.14, No.2, pp. 43-50, 2010, DOI:10.3970/icces.2010.014.043

Abstract A general elastoplastic fracture mechanics theory is proposed for applying the Essential-Work-of-Fracture (EWF) Method to quasi-static and impact toughness characterization. Advanced finite element modeling is developed to simulate the EWF Method using the crack-tip opening angle criterion (CTOA) and the constitutive relation of the material under consideration. For Poly(ethylene-terephlate) (PET) films, the load-displacement curves are calculated for the whole crack propagation process of deeply double-edge notched tensile specimens (DENT) with different ligament lengths so as to determine the total work, the essential work and the non-essential work of fracture. The effects of specimen gauge length More >

Xituan Shang^*, Michael R. T. Yen^1,†, M. Waleed Gaber^‡

Molecular & Cellular Biomechanics, Vol.7, No.2, pp. 93-104, 2010, DOI:10.3970/mcb.2010.007.093

Abstract The objective of this research is to conduct mechanical property studies of skin from two individual but potentially connected aspects. One is to determine the mechanical properties of the skin experimentally by biaxial tests, and the other is to use the finite element method to model the skin properties. Dynamic biaxial tests were performed on 16 pieces of abdominal skin specimen from rats. Typical biaxial stress-strain responses show that skin possesses anisotropy, nonlinearity and hysteresis. To describe the stress-strain relationship in forms of strain energy function, the material constants of each specimen were obtained and More >

Chyanbin Hwu^1,2, Mengchun Yu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.67, No.2, pp. 151-174, 2010, DOI:10.3970/cmes.2010.067.151

Abstract A comprehensive finite element model incorporating the features of comprehensive wing model and finite element method is developed in this paper. This new model extends the applicability of comprehensive wing model from uniform composite wings to tapered composite wings. It preserves the simplicity of one-dimensional finite element but performs like three-dimensional finite element for wing structural analysis. To verify its accuracy and show its efficiency, this model which is applicable to the general dynamic analysis is reduced to two simple cases: static analysis and free vibration analysis. Based upon the reduction results for static and More >

Soojin Cho¹, Jin-Hak Yi², Chung-Bang Yun¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.4, pp. 151-152, 2009, DOI:10.3970/icces.2009.012.151

Abstract The bridges are exposed to severe operational and environmental loadings, such as traffic, wind, and earthquake during their life time. Continuous exposure to such severe loadings may lead to structural damage requiring costly repair/retrofit and even may result in an unexpected disaster, which emphasizes the importance of assessing the current condition of bridges. From the last decade, FE model updating techniques based on the bridge dynamic characteristics are emerged to evaluate the current condition of bridges quantitatively. Most of the model updating techniques basically utilize an optimization process with an objective function built up by… More >

J. Noorzaei¹, K.H. Bayagoob², A.A. Abdulrazeg¹, M.S. Jaafar^1,1, T.A. Mohammed¹

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.1, pp. 43-60, 2009, DOI:10.3970/cmes.2009.047.043

Abstract This paper focuses on the development, verification and application of a three-dimensional finite element code for coupled thermal and structural analysis of roller compacted concrete dams. The Kinta RCC gravity dam, which is the first roller compacted concrete dam in Malaysia, has been taken for the purpose of verification of the finite element code. The actual climatic conditions and thermal properties of the materials were considered in the analysis. The structural stress analysis was performed using the elasto-plastic stress analysis. The Mohr yield criterion which is widely used for concrete plasticity modeling was adopted in More >

Xiaohua Hu¹, Gordana A. Cingara¹, David S. Wilkinson¹, Mukesh Jain², PeidongWu², Raja K. Mishra³

CMC-Computers, Materials & Continua, Vol.14, No.2, pp. 99-124, 2009, DOI:10.3970/cmc.2009.014.099

Abstract This work aims to understand the texture distribution in the localized necking band formed during uni-axial tension of AA5754 using an edge-constrained, plane strain post-necking FE model. The model domain is a long cross section of the band. Initial grain structure is mapped into the mesh from EBSD data using a modified Voroni-cell interpolation and considering pre-straining prior to localized necking. The material points in grains are assumed to exhibit isotropic elastoplastic behavior but have a relative strength in terms of Taylor factors which are updated by a Taylor-Bishop-Hill model. The predicted textures and gradients More >