Kang-Hyun Lee¹, Gun Jin Yun^1,2,*

CMC-Computers, Materials & Continua, Vol.66, No.1, pp. 87-112, 2021, DOI:10.32604/cmc.2020.012688

Abstract Re-melting process has been utilized to mitigate the residual stress level in the selective laser melting (SLM) process in recent years. However, the complex consolidation mechanism of powder and the different material behavior after the first laser melting hinder the direct implementation of the re-melting process. In this work, the effects of re-melting on the temperature and residual stress evolution in the SLM process are investigated using a thermo-mechanically coupled finite element model. The degree of consolidation is incorporated in the energy balance equation based on the thermodynamically-consistent phase-field approach. The drastic change of material properties due to the variation… More >

Ting Zang¹, Dongbin Zhu^2,*, Guowang Mu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.125, No.2, pp. 597-610, 2020, DOI:10.32604/cmes.2020.09965

Abstract According to the requirement of heterogeneous object modeling in additive manufacturing (AM), the Non-Uniform Rational B-Spline (NURBS) method has been applied to the digital representation of heterogeneous object in this paper. By putting forward the NURBS material data structure and establishing heterogeneous NURBS object model, the accurate mathematical unified representation of analytical and free heterogeneous objects have been realized. With the inverse modeling of heterogeneous NURBS objects, the geometry and material distribution can be better designed to meet the actual needs. Radical Basis Function (RBF) method based on global surface reconstruction and the tensor product surface interpolation method are combined… More >

Donghua Dai^1,2, Dongdong Gu^1,2,*, Qing Ge^1,2, Chenglong Ma^1,2, Xinyu Shi^1,2, Han Zhang^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.3, pp. 1085-1098, 2020, DOI:10.32604/cmes.2020.010927

Abstract The three-dimensional physical model of the randomly packed powder material irradiated by the laser beam was established, taking into account the transformation of the material phase, the melt spreading and the interaction of the free surface of the molten pool and the recoiling pressure caused by the material evaporation during the selective laser melting. Influence of the processing parameters on the thermal behavior, the material evaporation, the surface morphology and the densification behavior in the connection region of the molten pool and the substrate was studied. It was shown that the powder material underwent the transformation from the partial melting… More >

Zhaohui Xia^1,2, Zhihao He², Qifu Wang¹, Yingjun Wang^2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.2, pp. 703-720, 2020, DOI:10.32604/cmes.2020.010368

Abstract Additive manufacturing (AM), adding materials layer by layer, can be used to produce objects of almost any shape or geometry. However, AM techniques cannot accurately build parts with large overhangs, especially for the large features close to horizontal, hanging over the void. The overhangs will make the manufactured model deviate from the design model, which will result in the performance of the manufactured model that cannot satisfy the design requirements. In this paper, we will propose a new finite element (FE) analysis model that includes the manufacturing errors by mimicking the AM layer by layer construction process. In such FE… More >

Xiangyu Gao, Weidong Yang^*, Hongxuan Xian, Xiyuan Tu, Yuanyuang Wang^*

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.1, pp. 227-241, 2020, DOI:10.32604/cmes.2020.09923

Abstract This paper studies the binder droplet injection process in the 3DP technique. The mathematical model of the binder penetration process for multi-nozzle and multi-layer in 3DP technique is established, by using the conservation Level set method. According to the two-dimensional plane model of three-dimensional spatial structure of sand bed, the construction method of an equivalent cylindrical mapping infiltration model is proposed to represent the porosity of the model in the two-dimensional plane, which is exactly the same as that in the three-dimensional space, as well as closer to the arrangement of the three-dimensional space, and to realize the differentiation between… More >

Di Wang¹, Guangzhao Ye¹, Jingming Mai², Xiaomin Chen¹, Yongqiang Yang^1,*, Yang Li^1,*, Xiaojun Chen¹, Jie Chen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 1061-1077, 2020, DOI:10.32604/cmes.2020.09842

Abstract In this paper, a novel micromixer with complex 3D-shape inner units was put forward and fabricated by metal Additive Manufacturing (AM). The design of the micromixer combined the constraints of selective laser melting technology and the factors to improve mixing efficiency. Villermaux-Dushman reaction system and Compute Fluid Design (CFD) simulation were conducted to investigate the performance and the mechanism of this novel micromixer to improve mixing efficiency. The research found that the best mixing efficiency of this novel micromixer could be gained when the inner units divided fluid into five pieces with a uniform volume. Compared with a conventional micromixer… More >

Xinglong Wang^1,2, Cheng Wang^1,2, Xin Zhou^1,*, Mingkang Zhang³, Peiyu Zhang¹, Lei Wang²

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.2, pp. 495-508, 2020, DOI:10.32604/cmes.2020.09778

Abstract The new regenerative cooling thermal protection system exhibits the multifunctional characteristics of load-carrying and heat exchange cooling, which are fundamental for the lightweight design and thermal protection of hypersonic vehicles. Triply periodic minimal surface (TPMS) is especially suitable for the structural design of the internal cavity of regenerative cooling structures owing to its excellent structural characteristics. In this study, test pieces were manufactured using Ti6Al4V lightweight material. We designed three types of porous test pieces, and the interior was filled with a TPMS lattice (Gyroid, Primitive, I-WP) with a porosity of 30%. All porous test pieces were manufactured via selective… More >

Kerlin P. Robert¹, Jiaoyan Li², James D. Lee^1,*

Molecular & Cellular Biomechanics, Vol.16, Suppl.2, pp. 74-74, 2019, DOI:10.32604/mcb.2019.07125

Abstract This presentation focuses on the new and upcoming concept of 4D printing and its vast scope and importance in the research and development in industry. The 3D printing object is considered as a layered structure. Each layer may have different orientation. Therefore each layer may behave differently under the change of its environment. We formulate the theoretical shape changing process of 4D printing resulted from (I) the biological growth or swelling, (II) the change of temperature, and (III) the effect of electric field on piezoelectric material of the 3D printing product. Then we illustrate this theory visually through finite element… More >

Fuyao Yan^{1, #}, Yu hin Chan^2,#, Abhinav Saboo³ , Jiten Shah⁴, Gregory B. Olson^{1, 3}, Wei Chen^{2, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.3, pp. 343-366, 2018, DOI:10.31614/cmes.2018.04452

Abstract Predicting the mechanical properties of additively manufactured parts is often a tedious process, requiring the integration of multiple stand-alone and expensive simulations. Furthermore, as properties are highly location-dependent due to repeated heating and cooling cycles, the properties prediction models must be run for multiple locations before the part-level performance can be analyzed for certification, compounding the computational expense. This work has proposed a rapid prediction framework that replaces the physics-based mechanistic models with Gaussian process metamodels, a type of machine learning model for statistical inference with limited data. The metamodels can predict the varying properties within an entire part in… More >

Mahesh B. Mawale^1,*, Abhaykumar Kuthe², Dr. Padma Pawane³, Sandeep W. Dahake², Jyotilal S²

Molecular & Cellular Biomechanics, Vol.13, No.2, pp. 105-114, 2016, DOI:10.3970/mcb.2016.013.119

Abstract Purpose: The main purpose of this study is to develop a device for the indicative measurement of intraocular pressure (IOP) of eyeball, a key cause for glaucoma. In early diagnosis and treatment of glaucoma accurate measurement of IOP is important. The methods and devices which are available for the measurement of IOP have their own limitations which cause discomfort to the patients during measurement and needs anesthesia. There is a dare need of a device for the measurement of intraocular pressure by making the contact of plunger with closed eyelid eliminating the need of anesthesia and expert ophthalmologist. Method: Additive… More >