Weida Wu, Yiqiang Wang, Zhonghao Gao, Pai Liu^*

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.2, pp. 2001-2026, 2024, DOI:10.32604/cmes.2023.046670

Abstract Negative Poisson’s ratio (NPR) metamaterials are attractive for their unique mechanical behaviors and potential applications in deformation control and energy absorption. However, when subjected to significant stretching, NPR metamaterials designed under small strain assumption may experience a rapid degradation in NPR performance. To address this issue, this study aims to design metamaterials maintaining a targeted NPR under large deformation by taking advantage of the geometry nonlinearity mechanism. A representative periodic unit cell is modeled considering geometry nonlinearity, and its topology is designed using a gradient-free method. The unit cell microstructural topologies are described with the material-field series-expansion (MFSE) method. The… More >

Wenjun Chen¹, Yingjun Wang^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.27, No.3, pp. 1-1, 2023, DOI:10.32604/icces.2023. 09096

Abstract The rapid development of topology optimization has given birth to a large amount of different topology optimization methods, and each of them can manage a class of corresponding engineering problems. However, structures need to meet a variety of requirements in engineering application, such as lightweight and multiple load-bearing performance. To design composite structures that have multiple structural properties, a new multi-scale topology optimization method considering multiple structural performances is proposed in this paper. Based on the fitting functions of the result set and the bisection method, a new method to determine the weight coefficient is proposed in this paper, which… More >

Chenxi Xiu^1,2,*, Xihua Chu²

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.3, pp. 2305-2338, 2024, DOI:10.32604/cmes.2023.030194

Abstract This paper presents a micromechanics-based Cosserat continuum model for microstructured granular materials. By utilizing this model, the macroscopic constitutive parameters of granular materials with different microstructures are expressed as sums of microstructural information. The microstructures under consideration can be classified into three categories: a medium-dense microstructure, a dense microstructure consisting of one-sized particles, and a dense microstructure consisting of two-sized particles. Subsequently, the Cosserat elastoplastic model, along with its finite element formulation, is derived using the extended Drucker-Prager yield criteria. To investigate failure behaviors, numerical simulations of granular materials with different microstructures are conducted using the ABAQUS User Element (UEL)… More >

Wenjun Chen¹, Yingjun Wang^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.26, No.2, pp. 1-1, 2023, DOI:10.32604/icces.2023.09095

Abstract The rapid development of topology optimization has given birth to a large amount of different topology optimization methods, and each of them can manage a class of corresponding engineering problems. However, structures need to meet a variety of requirements in engineering application, such as lightweight and multiple load-bearing performance. To design composite structures that have multiple structural properties, a new multi-scale topology optimization method considering multiple structural performances is proposed in this paper. Based on the fitting functions of the result set and the bisection method, a new method to determine the weight coefficient is proposed in this paper, which… More >

Ke Ni¹, Zhengzhi Wang^1,2,3,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.25, No.4, pp. 1-2, 2023, DOI:10.32604/icces.2023.09248

Abstract Stimuli-responsive micropillar structures that can perform dynamics and reversible deformations according to external stimuli have been applied in a wide spectrum of fields, including object manipulation, soft miniature robots, and functional surfaces. However, it remains a challenge to exhibit programmable actuation behaviors for applications that require on-demand deformation response. Herein, a two-step photomask-assisted template casting technique is developed to fabricate a hybrid magnetic micropillar array for programmable actuation. By modulating the spatial distribution of the magnetic nanoparticles within the elastomer micropillars, the bending deformations of the micropillars with different particle distributions can vary near one order of magnitude under the… More >

Enzoh Langi¹, Liguo Zhao^2,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.25, No.3, pp. 1-1, 2023, DOI:10.32604/icces.2023.010163

Abstract Additive manufacturing emerges as an innovative technology to fabricate medical stents used to treat blocked arteries. However, there is a lack of study of underlying microstructure and mechanical properties of additively manufactured stent. In this work, additively manufactured 316L stainless steel stent was investigated, with electrochemical polishing being used to improve the surface finish. Microstructural characterisation was carried out using optical microscopy, scanning electron microscopy, and electron backscatter diffraction. The hardness and elastic modulus were measured using Berkovich nanoindentation, with an emphasis on the effect of grain orientation. In addition, spherical nanoindentation was used to obtain indentation stress-strain curves based… More >

Biao Li^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.25, No.1, pp. 1-2, 2023, DOI:10.32604/icces.2023.09818

Abstract High-temperature coatings are extensively used in aircraft engines and industrial gas turbines to protect hot-section components from harsh operating environments [1]. Representative high-temperature coatings include thermal barrier coatings and environmental barrier coatings, which are applied to substrates made of superalloy and ceramic matrix composites, respectively. The durability of the coatings is of significant importance for the structural integrity of the components [2-4]. A segmented microstructure was widely used to improve the coatings' durability. A network of through-thickness vertical cracks is introduced into the outer layer of the coatings, which increases the compliance of the coatings and therefore reduces the interfacial… More >

Kai Long^1,*, Xiaoyu Yang¹, Nouman Saeed¹, Zhuo Chen¹, Yi Min Xie²

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.1, pp. 293-310, 2021, DOI:10.32604/cmes.2021.012734

Abstract A methodology for achieving the maximum bulk or shear modulus in an elastic composite composed of two isotropic phases with distinct Poisson’s ratios is proposed. A topology optimization algorithm is developed which is capable of nding microstructures with extreme properties very close to theoretical upper bounds. The effective mechanical properties of the designed composite are determined by a numerical homogenization technique. The sensitivities with respect to design variables are derived by simultaneously interpolating Young’s modulus and Poisson’s ratio using different parameters. The so-called solid isotropic material with penalization method is developed to establish the optimization formulation. Maximum bulk or shear… More >

Zhanwei Liu, Huimin Xie, Fulong Dai

The International Conference on Computational & Experimental Engineering and Sciences, Vol.18, No.3, pp. 95-96, 2011, DOI:10.3970/icces.2011.018.095

Abstract The mechanical behaviors of microstructures and micro devices have drawn the attention from researchers on materials and mechanics recently. To understand the rule of these behaviors, the deformation measurement techniques with micro/nanometer sensitivity and spatial resolution are required. In this report, a geometric phase analysis technique, SEM scanning moirAC method, digital phase moirAC method based on gratings and a micro-marker identification method are introduced to meet the deformation evaluation requirement of MEMS. The geometric phase analysis technique is performed on the basis of regular gratings, instead of natural atom lattice. The regular gratings with a pitch of range from micrometer… More >

A.Y.Chen, J. Lu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.20, No.2, pp. 45-46, 2011, DOI:10.3970/icces.2011.020.045

Abstract The structural reliability of many brittle materials such as nanomaterials relies on the occurrence of intergranular, as opposed to transgranular, fracture in order to induce toughening by crack bridging. The current work examines the role of interface strength and grain size distribution in promoting intergranular fracture in order to maintain high toughening. A layered nanostructural 304SS sheet characterized by periodic distribution of nanocrystalline layers and micron-grained layers with graded grain size evolution has exhibited exceptional properties. The in situ SEM observations illustrate that an intergranular path and the consequent interface bridging process can be partitioned into five distinct regimes, namely:… More >