Modeling the Lamination of a Multilayered Tape Cast Ceramic Component With Fugitive Phases Before Sintering

2015 ◽  
Author(s):  
Stephanie A. Wimmer ◽  
Virginia G. DeGiorgi ◽  
Edward Gorzkowski
Keyword(s):  
Complex Geometry ◽  
Layer Structure ◽  
Ceramic Body ◽  
Dimensional Accuracy ◽  
Ceramic Component ◽  
Viscoelastic Deformation ◽  
Phase Layer ◽  
Phase Approach ◽  
Micro Channels ◽  
Tape Cast

A small finished ceramic component with micro-channels or other complex geometry requires a high degree of dimensional accuracy. The accuracy of the finished ceramic component depends upon the accuracy of the unfired ceramic body before sintering. One approach to creating micro-channels in ceramics is the fugitive phase approach. In this approach a sacrificial material is placed within the unfired ceramic to form channels or voids. The fugitive phase is removed or sacrificed during the subsequent sintering. For this paper, the authors examine the lamination step of the fugitive phase approach computationally. In the lamination step layers of unfired tape cast ceramic and layers of fugitive phase material are pressed together before sintering. The geometry examined in this paper is a quarter-symmetry model of a ten ceramic layer and nine fugitive phase layer structure. Three dimensional modeling is used to capture out of plane motion, displacement of the fugitive phase pieces, viscoelastic deformation, and rebounding when the layered structure is removed from the die press. The unfired ceramic is modeled as tape cast mullite and the fugitive phase is paper. The fugitive phase is modeled as linear elastic while the unfired ceramic is modeled as viscoelastic at a range of temperatures. The authors examine the filling of voids, pressure gradients, and conditions during unloading.

Modeling Tape Cast Ceramics With Multiple Layers of Fugitive Phase Materials

2012 ◽  
Author(s):  
Stephanie A. Wimmer ◽  
Ming-Jen Pan ◽  
Virginia G. DeGiorgi ◽  
Edward P. Gorzkowski ◽  
Alan C. Leung
Keyword(s):  
Ceramic Body ◽  
Experimental Investigations ◽  
Green Body ◽  
Ceramic Component ◽  
Viscoelastic Deformation ◽  
Ceramic Phase ◽  
Precise Control ◽  
Phase Approach ◽  
New Processing ◽  
Tape Cast

The fabrication of complex ceramic components requires new processing methods that are able to produce components with intricate geometries and accurate dimensions. The accuracy of the finished ceramic component depends upon precise control of the green ceramic body dimensions and uniformity prior to sintering. The authors are investigating the application of the fugitive phase approach, where a sacrificial material is used to form cavities or channels in the finished ceramic component. This paper, a continuation of a previous work, examines the lamination step of the fugitive phase approach for ceramic fabrication. The lamination step is where the fugitive phase pieces are combined with the tape cast green ceramic pieces. The multilayer green body is pressed to laminate the ceramic tape and fugitive phase layers together. Topological complexity is greatly increased when the tape cast ceramic pieces are interspersed with fugitive phase pieces to build up a consolidated multilayer green body. This paper examines the movement of the fugitive phase pieces, viscoelastic deformation of the ceramic phase, the filling of voids, pressure gradients, and the rebounding that occurs when the green ceramic body is removed from the press. This information will be used to complement parallel experimental investigations of the fugitive phase approach to ceramic fabrication.

Three Dimensional Modeling of Unfired Ceramics During Lamination

2014 ◽  
Author(s):  
Stephanie A. Wimmer ◽  
Ming-Jen Pan ◽  
Virginia G. DeGiorgi
Keyword(s):  
Ceramic Body ◽  
Three Dimensional ◽  
Experimental Investigations ◽  
Pressure Gradients ◽  
Viscoelastic Deformation ◽  
Ceramic Phase ◽  
Phase Approach ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Micro Channels

A finished ceramic component with complex geometries such as micro-channels requires a high degree of dimensional accuracy. This accuracy depends upon precise control of the unfired ceramic body before sintering. One method for creating precise micro-channel geometries is the fugitive phase approach. In this approach, a sacrificial material, the fugitive phase, is used to form channels or voids in the unfired ceramic body. The fugitive phase is removed or sacrificed during the subsequent sintering. For this paper, the authors examine the lamination step of the fugitive phase approach computationally. The lamination step is where the unfired ceramic and fugitive phase pieces are layered and pressed together to remove voids before sintering. The compression of the unfired ceramic during pressing causes pressure gradients, viscoelastic deformation, displacement of the fugitive phase pieces, and rebounding. Three dimensional modeling is used to capture out of plane movement or bending of the long fugitive phase pieces that are used to form long micro-channels. For this research, the unfired ceramic phase consists of tape cast mullite and the fugitive phase is paper. This work primarily examines viscoelastic material models of the unfired ceramic phase for a range of temperatures. The filling of voids, movement of the fugitive phases, pressure gradients, and the rebounding that occurs when the unfired ceramic body is removed from the die press are also noted. The information obtained from computational simulations is used to help direct concurrent experimental investigations.

Three Dimensional Modeling of the Lamination of Unfired Ceramics With Fugitive Phases

2014 ◽  
Author(s):  
Stephanie A. Wimmer ◽  
Ming-Jen Pan ◽  
Virginia G. DeGiorgi
Keyword(s):  
Ceramic Body ◽  
Three Dimensional ◽  
Experimental Investigations ◽  
Pressure Gradients ◽  
Viscoelastic Deformation ◽  
Ceramic Phase ◽  
Phase Approach ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Ceramic Components

The dimensional accuracy of finished ceramic components depends upon the precise control of the unfired ceramic body prior to sintering. One approach for creating precise geometries is the fugitive phase approach. In the fugitive phase approach, the fugitive phase is a sacrificial material that can be removed to form channels in the finished ceramic component. In this paper, the authors computationally examine the fugitive phase approach; in particular, the lamination step of the fugitive phase approach is modeled. In the lamination step the unfired ceramic phases are combined with the fugitive phases through the application of pressure. For this research, the unfired ceramic phase consists of tape cast mullite and the fugitive phase is paper. These phases are laminated together in a die press to form a multilayer material. The compression of the die press causes pressure gradients, viscoelastic deformation, and rebounding of the unfired ceramic phases. In addition, the die press can cause movement of the fugitive phase pieces leaving unfilled voids. Three dimensional modeling is necessary to accurately capture the movement of the fugitive phase pieces. In this work the authors examine the viscoelastic deformation of the unfired ceramic phase, movement of the fugitive phase, the creation and filling of voids, pressure gradients, and the rebounding that occurs when the unfired ceramic body is removed from the die press. The information obtained from computational simulations will be used to help direct experimental investigations of the fugitive phase approach for fabrication of complex ceramic components.

scholarly journals Analysis of AC Transport Loss in Conductor on Round Core Cables

2021 ◽  
Author(s):  
Jiabin Yang ◽  
Chao Li ◽  
Mengyuan Tian ◽  
Shuyu Liu ◽  
Boyang Shen ◽  
...  
Keyword(s):  
Eddy Current ◽  
Complex Geometry ◽  
Layer Structure ◽  
Single Layer ◽  
Element Model ◽  
Structure Design ◽  
Ac Loss ◽  
Shielding Effect ◽  
Transport Loss ◽  
Electro Magnetic

AbstractThe conductor on round core (CORC) cable wound with second-generation high-temperature superconducting (HTS) tapes is a promising cable candidate with superiority in current capacity and mechanical strength. The composing superconductors and the former are tightly assembled, resulting in a strong electro-magnetic interaction between them. Correspondingly, the AC loss is influenced by the cable structure. In this paper, a 3D finite-element model of the CORC cable is first built, and it includes the complex geometry, the angular dependence of critical current and the periodic settings. The modelling is verified by the measurements conducted for the transport loss of a two-layer CORC cable. Subsequently, the simulated results show that the primary transport loss shifts from the former to the superconductors as the current increases. Meanwhile, the loss exhibited in the outer layer is larger than that of the inner layer, which is caused by the shielding effect among layers and the former. This also leads to the current inhomogeneity in CORC cables. In contrast with the two-layer case, the simulated single-layer structure indicates stronger frequency dependence because the eddy current loss in the copper former is always dominant without the cancellation of the opposite-wound layers. The core eddy current of the single structure is denser on the outer surface. Finally, the AC transport losses among a straight HTS tape, a two-layer cable and a single-layer cable are compared. The two-layer structure is confirmed to minimise the loss, meaning an even-numbered arrangement makes better use of the cable space and superconducting materials. Having illustrated the electro-magnetic behaviour inside the CORC cable, this work is an essential reference for the structure design of CORC cables.

Influence of the manufacturing parameters of an AlMg5 wire–based hybrid production process on quality and mechanical properties

2021 ◽  
Author(s):  
Hans-Christian Möhring ◽  
Dina Becker ◽  
Rocco Eisseler ◽  
Thomas Stehle ◽  
Tim Reeber
Keyword(s):  
Mechanical Properties ◽  
Production Process ◽  
Complex Geometry ◽  
Lightweight Design ◽  
Dimensional Accuracy ◽  
Manufacturing Processes ◽  
Shape Accuracy ◽  
Hybrid Production ◽  
Traditional Manufacturing ◽  
Subtractive Machining

AbstractHybrid manufacturing processes are known for combining the advantages of additive manufacturing and more traditional manufacturing processes such as machining to create components of complex geometry while minimising material waste. The trend towards lightweight design, especially in view of e-mobility, gives aluminium materials an important role to play. This study examines the use of aluminium alloys in laser metal wire deposition (LMWD) processes with subsequent subtractive machining, which is considerably more difficult due to the different process-related influences. The investigations are focussed on the influence of the differently controlled laser power on the shape accuracy, the microstructure, and the hardness of the AlMg5 test components after the LMWD process with subsequent subtractive machining by turning. The long-term goal of the investigations is to increase the stability of the hybrid production process of AlMg5 components with defined dimensional accuracy and mechanical properties.

A Numerical Model of Adhesion Property of Malaria Infected Red Blood Cells in Micro Scale Blood Flows

2009 ◽  
Author(s):  
Yohsuke Imai ◽  
Hitoshi Kondo ◽  
Young Ho Kang ◽  
Takuji Ishikawa ◽  
Chwee Teck Lim ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Adhesion Molecule ◽  
Blood Cells ◽  
Complex Geometry ◽  
Three Dimensional ◽  
Experimental Techniques ◽  
Receptor Interaction ◽  
Micro Scale ◽  
Micro Channels ◽  
Adhesive Interactions

Infection by malaria parasite changes mechanical properties of red blood cells (RBCs). Infected red blood cells (IRBCs) lose the deformability but also develop the ability to cytoadhere and rosetting. These outcomes can lead to microvascular blockage [1]. The stiffness of IRBCs [2] and its effects on the flow in micro channels [3] were studied with recent experimental techniques. The cytoadherence and rosetting properties of IRBCs have also been studied experimentally. The cytoadherence is mediated by the interaction of the parasite protein PfEMP1 with several endothelial adhesion molecules, such as CD36, intercellular adhesion molecule-1 (ICAM-1), P-selectin, and vascular cell adhesion molecule-1 (VCAM-1) [4]. In particular, the ligand-receptor interaction between PfEMP1 and CD36 shows tight adhesion [5]. Microvascular blockage may be a hemodynamic problem, involving the interactions between IRBCs, healthy RBCs (HRBCs) and endothelial cells (ECs) in flowing blood, but however experimental techniques have several limitations to this topic. First, it is still difficult to observe the RBC behavior interacting with many other cells even with the recent confocal microscopy. Second, the three-dimensional information on flow field is hardly obtained. Third, capillaries in human body are circular channels with complex geometry, but such complex channels cannot be created in micro scale. Instead, numerical modeling can overcome these problems. We presented a two-dimensional hemodynamic model involving adhesive interactions [6]. In this paper, we propose a three-dimensional model of the adhesive interactions for micro scale hemodynamics in malaria infection.

B-spline contour curve approximation and deformation analysis of complex ceramic core

2018 ◽  
Vol 233 (6) ◽  
pp. 1663-1673 ◽  
Author(s):  
Xiandong Zhang ◽  
Kun Bu
Keyword(s):  
Cross Section ◽  
Complex Geometry ◽  
Local Maximum ◽  
Dimensional Accuracy ◽  
Deformation Analysis ◽  
Ceramic Core ◽  
B Spline ◽  
Maximum Curvature ◽  
Dominant Points ◽  
The Cross

Complex ceramic core is the critical part for manufacturing hollow turbine blade in the investment casting process. The complex geometry, small inner structures and high-precision requirements of ceramic cores make them difficult to fabricate, and the shape and dimensional accuracy of ceramic cores are very low in factory practice. To understand the deformation characteristics of ceramic cores, a noisy points recognition algorithm, an extraction method of measuring cross-section contour points and a B-spline iterative fitting algorithm using dominant points of chord deviation are proposed. First, the cross-section contour points were provided through registration, slicing and intersection methods. Second, the noisy points were deleted by convex noisy points and concave noisy points recognition algorithms. Third, the cross-section contour curve of the ceramic core was fitted through B-spline iterative fitting method with chord deviation dominant points. The curves fitted with chord deviation points and curves fitted with local maximum curvature points were compared with simulating data and scanning data, respectively, and the results show that B-spline fitting curve needs fewer chord deviation points than local maximum curvature points, 24.4% fewer in simulation validation and 12.5% fewer in experimental validation. In the end, the bending deformation, torsion deformation and shrinkage deformation errors of ceramic core are established by fitting contour curves of serial cross sections of the ceramic core.

scholarly journals A Semi-Dissolving Microneedle Patch Incorporating TEMPO-Oxidized Bacterial Cellulose Nanofibers for Enhanced Transdermal Delivery

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1873 ◽  
Author(s):  
Ji Eun Song ◽  
Seung-Hyun Jun ◽  
Sun-Gyoo Park ◽  
Nae-Gyu Kang
Keyword(s):  
Bacterial Cellulose ◽  
Transdermal Delivery ◽  
Layer Structure ◽  
Drug Loading ◽  
Cellulose Nanofibers ◽  
Absorption Capacity ◽  
Water Soluble ◽  
Micro Channels ◽  
Backing Layer

Although dissolving microneedles have garnered considerable attention as transdermal delivery tools, insufficient drug loading remains a challenge owing to their small dimension. Herein, we report a one-step process of synthesizing semi-dissolving microneedle (SDMN) patches that enable effective transdermal drug delivery without loading drugs themselves by introducing TEMPO-oxidized bacterial cellulose nanofibers (TOBCNs), which are well dispersed, while retaining their unique properties in the aqueous phase. The SDMN patch fabricated by the micro-molding of a TOBCN/hydrophilic biopolymer mixture had a two-layer structure comprising a water-soluble needle layer and a TOBCN-containing insoluble backing layer. Moreover, the SDMN patch, which had a hole in the backing layer where TOBCNs are distributed uniformly, could offer novel advantages for the delivery of large quantities of active ingredients. In vitro permeation analysis confirmed that TOBCNs with high water absorption capacity could serve as drug reservoirs. Upon SDMN insertion and the application of drug aqueous solution through the drug inlet hole, the TOBCNs rapidly absorbed the solution and supplied it to the needle layer. Simultaneously, the needle layer dissolved in body fluids and the drug solution to form micro-channels, which enabled the delivery of larger quantities of drugs to the skin compared to that enabled by solution application alone.

PVC Sheet Blow Forming Finite Element Simulation and Experimental Study

2011 ◽  
Vol 467-469 ◽  
pp. 1846-1851 ◽  
Author(s):  
Chao Zheng ◽  
Yi Sheng Zhang ◽  
De Qun Li
Keyword(s):  
Finite Element ◽  
Complex Geometry ◽  
Experimental Testing ◽  
Thickness Distribution ◽  
Dimensional Accuracy ◽  
Sheet Forming ◽  
Forming Process ◽  
Plastic Sheet ◽  
Element Simulation

The plastic sheet forming technique is simple and easy to realize, that is why, it is widely used for packaging commodities. Similarly, in In-Mold-Decoration (IMD) molding technology, due to the complex geometry of the membrane and the high requirement of the dimensional accuracy, geometric design and molding technique for the product should be focused on controlling the thickness distribution of shell or membrance plastic products in order to achieve high precision manufacturing. This paper started with analyzing the performance data of the plastic sheet molding material, using nonlinear finite element method and multi-physics coupling method to simulate the plastic sheet forming process, and the result gives the required parameters for product design and quality control. For the thickness deviation, the experimental testing shows that the maximum discrepancy between the simulation and actual result is less than15%. The research proved that computer simulation can contribute to control the inhomogeneity of the shell or membrane so as to improve the design and the quality of manufacturing.

Enhancement of Porosity of the Ceramic Shell in Investment Casting Process Using Needle Coke and Camphor

2014 ◽  
Vol 592-594 ◽  
pp. 269-275 ◽  
Author(s):  
Khyati Tamta ◽  
D. Benny Karunakar
Keyword(s):  
Investment Casting ◽  
Complex Geometry ◽  
Gas Permeability ◽  
Ferrous Metal ◽  
Dimensional Accuracy ◽  
Casting Process ◽  
Ceramic Shell ◽  
Needle Coke ◽  
Thin Sections ◽  
Investment Casting Process

Investment casting process has been a widely used process for centuries. It is known for its ability to produce components of complex shapes with dimensional accuracy and excellent surface finish. Investment casting has been used to make manufacture weapons, jewellery and art castings during the ancient civilization and today it is used to manufacture engineering components. In Investment casting wax patterns are made by wax injection and then coating of the wax patterns are done by ceramic slurry, made with silica flour and binder. After dewaxing and firing molten metal is poured in the shell and solidified casting can be achieved. Investment casting can be cast any ferrous and non ferrous metal which is difficult in die casting. Finishing operations are negligible and very thin sections as.75mm can also be cast which is not possible in sand casting but there are many challenges in Investment casting. It is relatively slow process because preparation of ceramic shell consumes a lot of time, permeability of shell is very low which causes gas permeability. Incorporation of chills is very difficult. Among all these challenges gas porosity is main problem because of poor permeability, entrapment of gases due to complex geometry of the shell, reuse of scrap metal. In the present work porosity of the shell can be increase by addition of mixture of Camphor and needle coke. After firing of the shell camphor and needle coke will be burnt leaving pores for the escape of entrapped gases. Mechanical properties of the both shell will be compared with each other.

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