J. Sladek, V. Sladek, M. Wonsche, Ch. Zhang

The International Conference on Computational & Experimental Engineering and Sciences, Vol.18, No.3, pp. 79-80, 2011, DOI:10.3970/icces.2011.018.079

Abstract It is well known that the coupling nature of piezoelectric materials has led to their wide applications. Interface failure is one of the most dominant failure mechanisms in laminated piezoelectric elements and structures. A meshless method based on the local Petrov-Galerkin approach is proposed, to solve the interface crack problem between two dissimilar piezoelectric solids. Permeable and impermeable electrical boundary conditions are considered on the crack faces. Stationary governing equations for electrical fields and the elastodynamic equations with an inertial term for two-dimensional (2-D) mechanical fields are considered. Nodal points are spread on the analyzed domain, and each node is… More >

Hiromichi Nagao^1,2,*, Shin-ichi Ito^1,2, Tadashi Kasuya³, Junya Inoue^4,3

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.2, pp. 127-127, 2019, DOI:10.32604/icces.2019.05384

Abstract Data assimilation (DA) is a computational technique to integrate numerical simulation models and observational/experimental data based on Bayesian statistics. DA is accepted as an essential methodology for the modern weather forecasting, and is applied to various fields of science including structural materials science. We propose a DA methodology to evaluate unobservable parameters involved in multi-phase-field models with the aim of accurately predicting the observed grain growth, such as in metals and alloys. This approach integrates models and a set of observational image data of grain structures. Since the set of image data is not a time series, directly applying conventional… More >

Taku Nonomura

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.4, pp. 73-74, 2019, DOI:10.32604/icces.2019.05266

Abstract In this presentation, a family of Kalman filter dynamic mode decomposition, which consists of algorithms of the linear Kalman filter DMD method which identify the linear system and the extended Kalman filter DMD method which simultaneously identify the system and estimates state variable, is introduced. Then, the application of the extended Kalman filter DMD to data assimilation is discussed. More >

P.D. Shah¹, C.L. Tan¹, X. Wang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.2, pp. 75-80, 2007, DOI:10.3970/icces.2007.001.075

Abstract The path-independent mutual- or M-integral for the computation of the T-stress for interface cracks lying between dissimilar anisotropic, linear elastic solids is developed in this paper. For the numerical stress analysis, the Boundary Element Method (BEM) is employed and special crack-tip elements with the proper oscillatory traction singularity are used. The successful implementation of the scheme for evaluating the T-stress of an interface crack between anisotropic bi-materials with BEM is demonstrated by numerical examples. More >

Zakia Khelifi^1,2, Mohammed Amine Allal², Nabil Abou-bekr², Saïd Taïbi¹, Benoît Duchemin^1*

Journal of Renewable Materials, Vol.6, No.3, pp. 336-346, 2018, DOI:10.7569/JRM.2018.634102

Abstract The in-soil biodegradation of Stipa tenacissima (alfa) leaves was examined. Non-linear mechanical testing was performed at various biodegradation stages. Tensile strength, loading and unloading Young's moduli and dissipation energy decreased with the burial time, whereas plasticity increased. Field-emission scanning electron microscopy (FE-SEM) showed that the fracture cracks propagated in the longitudinal direction in the raw material, resulting in a fracture mode consisting of a mixture of middle lamella delamination and fiber pull-out. In contrast, the cracks were perpendicular to the stem axis in the biodegraded material, demonstrating an important strength loss of the load-bearing fibers. This strength loss was correlated… More >

Mohamed Ammar¹, Ramzi Khiari^2,3,4*, Mohamed Naceur Belgacem^3,4*, Elimame Elaloui¹

Journal of Renewable Materials, Vol.5, No.2, pp. 116-123, 2017, DOI:10.7569/JRM.2016.634136

Abstract The present study investigated the preparation of biomatrices from Stipa tenacissima L. and its valorization for fiberboard application. Resins were produced by extracting lignin from the Stipa tenacissima L. black liquor by soda process and combining it with glyoxal as crosslinking agent to produce lignin-glyoxal-resin (LGR). The matrix was characterized by several methods, such as FTIR and ATG/ATD, and then mixed with date palm rachis as reinforcing fibers in different proportions of 30 and 50% (w/w with respect to the matrix) to produce biodegradable composite materials. Then, their thermal and mechanical properties were determined, using differential scanning calorimetry (DSC) and… More >

S. S. Pulla¹, Y. C. Lu²

CMC-Computers, Materials & Continua, Vol.29, No.3, pp. 263-278, 2012, DOI:10.3970/cmc.2012.029.263

Abstract The nanoindentation technique is used to quantify the interfaces between dissimilar materials. The interfaces can be generally referred as to the transition regions in polymers due to environmental aging, or the regions between fibers and polymer matrix in composites, or other similar situations. It is proposed to use a nanoindenter equipped with small spherical tip to cross-indent the interfaces of dissimilar materials. The nanoindentation tests were carried out through 3-dimensional finite element simulations with varying properties of the two dissimilar materials, including various combinations of modulus (E₁/E₂), yield strength (σ_y1/σ_y2), hardening index (n₁/n₂), and the interface sizes (R/T). The mechanical… More >

P.D. Shah¹, C.L. Tan^1,2, X. Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.13, No.3, pp. 185-198, 2006, DOI:10.3970/cmes.2006.013.185

Abstract In this paper, the path independent mutual or M-integral for the computation of the T-stress for interface cracks between dissimilar anisotropic, linear elastic solids, is developed. The required auxiliary field solution is derived from the solution of the problem of an anisotropic composite wedge subjected to a point force at its apex. The Boundary Element Method (BEM) is employed for the numerical stress analysis in which special crack-tip elements with the proper oscillatory traction singularity are used. The successful implementation of the procedure for evaluating the T-stress in a bi-material interface crack and its application are demonstrated by numerical examples. More >

W. Attaporn¹, H. Koguchi²

CMES-Computer Modeling in Engineering & Sciences, Vol.39, No.3, pp. 237-262, 2009, DOI:10.3970/cmes.2009.039.237

Abstract In the present study, a stress singularity field along free edges meeting at a corner in a three-dimensional joint structure is investigated. The order of stress singularity is determined using an eigen analysis based on a finite element method. Intensities of stress singularity not only at the corner but also along the free edge of interface are determined directly without any post-processing by a new FEM formulation referred to as a three-dimensional enriched FEM. Result in the present analysis is also compared with that in another numerical method. It was slightly larger than the intensity of stress singularity, which was… More >

Chyanbin Hwu¹, T.L. Kuo, Y.C. Chen

CMC-Computers, Materials & Continua, Vol.11, No.3, pp. 165-184, 2009, DOI:10.3970/cmc.2009.011.165

Abstract In this paper the near tip solutions for interface corners written in terms of the stress intensity factors are presented in a unified expression. This single expression is applicable for any kinds of interface corners including corners and cracks in homogeneous materials as well as interface corners and interface cracks lying between two dissimilar materials, in which the materials can be any kinds of linear elastic anisotropic materials or piezoelectric materials. Through this unified expression of near tip solutions, the singular orders of stresses and their associated stress/electric intensity factors for different kinds of interface problems can be determined through… More >