Shuai Chen¹, Yinwei Ma², Zhongshu Wang², Zongmei Xu³, Song Zhang¹, Jianle Li¹, Hao Xu¹, Zhanjun Wu^1,*

Structural Durability & Health Monitoring, Vol.18, No.2, pp. 125-141, 2024, DOI:10.32604/sdhm.2024.042594

Abstract The safety and integrity requirements of aerospace composite structures necessitate real-time health monitoring throughout their service life. To this end, distributed optical fiber sensors utilizing back Rayleigh scattering have been extensively deployed in structural health monitoring due to their advantages, such as lightweight and ease of embedding. However, identifying the precise location of damage from the optical fiber signals remains a critical challenge. In this paper, a novel approach which namely Modified Sliding Window Principal Component Analysis (MSWPCA) was proposed to facilitate automatic damage identification and localization via distributed optical fiber sensors. The proposed method is able to extract signal… More > Graphic Abstract

Mingjing Li^1,*, Leiting Dong¹, Satya N. Atluri²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.27, No.4, pp. 1-2, 2023, DOI:10.32604/icces.2023.09689

Abstract The Fragile Points Method (FPM) is a discontinuous meshless method based on the Galerkin weak form [1]. In the FPM, the problem domain is discretized by spatial points and subdomains, and the displacement trial function of each subdomain is derived based on the points within the support domain. For this reason, the FPM doesn’t suffer from the mesh distortion and is suitable to model complex structural deformations. Furthermore, similar to the discontinuous Galerkin finite element method, the displacement trial functions used in the FPM is piece-wise continuous, and the numerical flux is introduced across each interior interface to guarantee the… More >

Nadom K. Mutlib^1,*, Muna N. Ismael¹, Shahrizan Baharom²

Structural Durability & Health Monitoring, Vol.15, No.3, pp. 227-246, 2021, DOI:10.32604/sdhm.2021.010725

Abstract Structural health monitoring employs different tools and techniques to provide a prediction for damages that occur in various structures. Damages such as debond and cracks in concrete-filled steel tube column (CFST) are serious defects that threaten the integrity of the structural members. Ultrasonic waves monitoring applied to the CFST column is necessary to detect damages and quantify their size. However, without appropriate signal processing tools, the results of the monitoring process could not be crucial. In this research, a monitoring process based on a Multiphysics numerical simulation study was carried out. Two signal processing tools: short time Fourier transform (STFT)… More >

Jihong Hu, Mingqing Sun^*, Wei Huang, Yingjun Wang

CMES-Computer Modeling in Engineering & Sciences, Vol.127, No.1, pp. 191-207, 2021, DOI:10.32604/cmes.2021.015365

Abstract Strain hardening cement-based composites (SHCC) beam externally bonded with glass fiber-reinforced polymer (FRP) plate was examined under three-point flexural test. The effects of the type of substrate used (plain cement mortar vs. SHCC), the use or not of a FRP plate to strengthen the SHCC beam, and the thickness of the FRP plate on the flexural performances were studied. Results show that the ultimate load of SHCC beams strengthened with FRP plate has improved greatly in comparison with plain SHCC beams. The deformation capacity of beams makes little change with an increase in the thickness of FRP plates. The formation… More >

Xizhi Wu^1,2, Xueyou Huang³, Xianjun Li^1,*, Yiqiang Wu¹

Journal of Renewable Materials, Vol.7, No.12, pp. 1295-1307, 2019, DOI:10.32604/jrm.2019.07839

Abstract This study presents a new structure made up of bamboo scrimber and carbon fiber reinforced polymer (CFRP) to address the low stiffness and strength of bamboo scrimbers. Three-point bending test and finite element model were conducted to study the failure mode, strain-displacement relationship, load-displacement relationship and relationships between strain distribution, contact pressure and deflection, and adhesive debonding. The results indicated that the flexural modulus and static flexural strength of the composite beams were effectively increased thanks to the CFRP sheets. The flexural modulus of the composite specimens were 2.33-2.94 times that of bamboo scrimber beams, and the flexural strength were… More >

B.R.Kim¹ and H.K.Lee^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.3, pp. 253-282, 2009, DOI:10.3970/cmes.2009.047.253

Abstract Damage characteristic of particulated ductile composites is a complex evolutionary phenomenon that includes particle debonding and void evolution with the accumulation of the plastic straining of the ductile matrix. In this paper, a micromechanical elastoplastic damage model for ductile matrix composites considering gradually incremental damage (particle debonding and void evolution) is proposed to predict the overall elastoplastic behavior and damage evolution in the composites. The constitutive damage model proposed in an earlier work by the authors [Kim and Lee (2009)] considering particle debonding is extended to accommodate the gradually incremental damage and elastoplastic behavior of the composites. On the basis… More >

E. H. Glaessgen¹, W.T. Riddell², I. S. Raju¹

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.1, pp. 103-116, 2002, DOI:10.3970/cmes.2002.003.103

Abstract The effects of several critical assumptions and parameters on the computation of strain energy release rates for delamination and debond configurations modeled with plate elements have been quantified. The method of calculation is based on the virtual crack closure technique (VCCT), and models of the upper and lower surface of the delamination or debond that use two-dimensional (2D) plate elements rather than three-dimensional (3D) solid elements. The major advantages of the plate element modeling technique are a smaller model size and simpler configurational modeling. Specific issues that are discussed include: constraint of translational degrees of freedom, rotational degrees of freedom… More >

R. Han¹, M.S. Ingber¹, H.L. Schreyer¹

CMC-Computers, Materials & Continua, Vol.4, No.3, pp. 163-176, 2006, DOI:10.3970/cmc.2006.004.163

Abstract Decohesion is an important failure mode associated with fiber-reinforced composite materials. Analysis of failure progression at the fiber-matrix interfaces in fiber-reinforced composite materials is considered using a softening decohesion model consistent with thermodynamic concepts. In this model, the initiation of failure is given directly by a failure criterion. Damage is interpreted by the development of a discontinuity of displacement. The formulation describing the potential development of damage is governed by a discrete decohesive constitutive equation. Numerical simulations are performed using the direct boundary element method. Incremental decohesion simulations illustrate the progressive evolution of debonding zones and the propagation of cracks… More >

Qiubao Ouyang¹, Di Zhang^1,2, Xinhai Zhu³, Zhidong Han³

CMC-Computers, Materials & Continua, Vol.41, No.1, pp. 37-54, 2014, DOI:10.3970/cmc.2014.041.037

Abstract The present work is to investigate the failure mechanisms in the deformation of silicon carbide (SiC) particle reinforced aluminum Metal Matrix Composites (MMCs). To better deal with crack growth, a new numerical approach: the MLPG-Eshelby Method is used. This approach is based on the meshless local weak-forms of the Noether/Eshelby Energy Conservation Laws and it achieves a faster convergent rate and is of good accuracy. In addition, it is much easier for this method to allow material to separate in the material fracture processes, comparing to the conventional popular FEM based method. Based on a statistical method and physical observations,… More >

Paria Naghipour¹, Evan J. Pineda², Steven M. Arnold²

CMC-Computers, Materials & Continua, Vol.35, No.1, pp. 17-33, 2013, DOI:10.3970/cmc.2013.035.017

Abstract The micromechanics theory, generalized method of cells (GMC), was employed to simulate the debonding of fiber/matrix interfaces, within a repeating unit cell subjected to global, cyclic loading, utilizing a cyclic crack growth law. Cycle dependent, interfacial debonding was implemented as a new module to the available GMC formulation. The degradation of interfacial stresses with applied load cycles was achieved via progressive evolution of the interfacial compliance A periodic repeating unit cell, representing the fiber/matrix architecture of a composite, was subjected to combined normal and shear loadings, and degradation of the global transverse stress in successive cycles was monitored. The obtained… More >