scholarly journals A Finite Element Analysis for Improvement of Shaping Process of Complex-Shaped Large-Size Silicon Carbide Mirrors

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4136
Author(s):  
Ling Qiao ◽  
Jingchuan Zhu ◽  
Yingnan Wan ◽  
Congcong Cui ◽  
Ge Zhang
Keyword(s):  
Silicon Carbide ◽  
Finite Element ◽  
Structural Integrity ◽  
Casting Process ◽  
Green Body ◽  
Technological Parameters ◽  
Element Analysis ◽  
Gel Casting ◽  
Generation Mechanisms

In the gel-casting process, the proper selection of technological parameters is crucial for the final quality of a green body. In this work, the finite element method is used to investigate the mold characteristics in the gel-casting process, and the typical flow behaviors under different conditions are presented. Based on the distribution characteristics of temperature, pressure and flow field of gel polymer, the simulated results provide some possible reasons for the generation mechanisms of defects. Then, a series of simulations were performed to investigate the effect of process parameters on the molding quality of green gel-cast bodies. The results show that the decreasing loading speed can effectively reduce the number of defects and improve the molding quality. In addition, this paper presents a new technique by applying the exhaust hole to decrease the number of defects and, hence, improve structural integrity. The influence of the loading speed on the mold characteristics is well understood for the gating system with an exhaust hole, which suggests to us appropriate parameters for optimizing the molding design. This work provides a theoretical basis to explicate the generating mechanism of defects involved in the gel-casting process and acquires an optimized technique to produce a silicon carbide green body.

Preparation of RBSC Green Bodies by Gel-Casting

2008 ◽  
Vol 368-372 ◽  
pp. 834-836
Author(s):  
Hai Lin Liu ◽  
Yu Feng Chen ◽  
Hua Wang ◽  
Jie Tang
Keyword(s):  
Silicon Carbide ◽  
Flexural Strength ◽  
Monomer Concentration ◽  
Casting Process ◽  
Green Body ◽  
Carbon Particles ◽  
Gel Casting ◽  
Monomer Content ◽  
Silicon Carbide Particles ◽  
Carbide Particles

In this paper, green bodies of RBSC were prepared through the gel-casting process. The effects of monomer concentration and ratio of MBAM to AM on the strength and microstructure of the green bodies were studied. When the monomer content increased from 10wt% to 20wt %( relative to water in the slurry), the flexural strength increases efficiency. However, the flexural strength decreases when the monomer content was above 20wt%. Similarly, when the ratio of MBAM to AM increased from 1/19 to 1/9, it had the same effects on the flexural strength of green bodies. It was found that silicon carbide particles were packaged by the carbon particles with gel. When the monomer content was 20wt% and the ratio of MBAM to AM was 1/9, the green body showed the best homogeneous microstructures and its flexural strength achieved 8MPa.

Towards Predicting Relative Belt Edge Endurance With the Finite Element Method

1990 ◽  
Vol 18 (4) ◽  
pp. 216-235 ◽  
Author(s):  
J. De Eskinazi ◽  
K. Ishihara ◽  
H. Volk ◽  
T. C. Warholic
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Shear Deformations ◽  
Element Analysis ◽  
Vertical Loading ◽  
Predicted Values ◽  
Element Method

Abstract The paper describes the intention of the authors to determine whether it is possible to predict relative belt edge endurance for radial passenger car tires using the finite element method. Three groups of tires with different belt edge configurations were tested on a fleet test in an attempt to validate predictions from the finite element results. A two-dimensional, axisymmetric finite element analysis was first used to determine if the results from such an analysis, with emphasis on the shear deformations between the belts, could be used to predict a relative ranking for belt edge endurance. It is shown that such an analysis can lead to erroneous conclusions. A three-dimensional analysis in which tires are modeled under free rotation and static vertical loading was performed next. This approach resulted in an improvement in the quality of the correlations. The differences in the predicted values of various stress analysis parameters for the three belt edge configurations are studied and their implication on predicting belt edge endurance is discussed.

Tire Bead Overheating in Urban Buses and Trucks Using Drum Brake Systems

1998 ◽  
Vol 26 (1) ◽  
pp. 51-62
Author(s):  
A. L. A. Costa ◽  
M. Natalini ◽  
M. F. Inglese ◽  
O. A. M. Xavier
Keyword(s):  
Heat Transfer ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Energy ◽  
Structural Integrity ◽  
Experimental Temperature ◽  
Temperature Profiles ◽  
Element Analysis ◽  
Drum Brake ◽  
Fea Model

Abstract Because the structural integrity of brake systems and tires can be related to the temperature, this work proposes a transient heat transfer finite element analysis (FEA) model to study the overheating in drum brake systems used in trucks and urban buses. To understand the mechanics of overheating, some constructive variants have been modeled regarding the assemblage: brake, rims, and tires. The model simultaneously studies the thermal energy generated by brakes and tires and how the heat is transferred and dissipated by conduction, convection, and radiation. The simulated FEA data and the experimental temperature profiles measured with thermocouples have been compared giving good correlation.

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

Casing Design for an Oxygen Concentrator

1999 ◽  
Author(s):  
Stephanie H. Swindle ◽  
Beth A. Todd ◽  
James F. Cuttino
Keyword(s):  
Quality Of Life ◽  
Structural Integrity ◽  
Chronic Obstructive ◽  
Gas Mixture ◽  
Improve Quality ◽  
Chronic Obstructive Pulmonary Disorder ◽  
Element Analysis ◽  
Pulmonary Disorder ◽  
Oxygen Concentrator

Abstract Human bodies depend on a steady flow of oxygen for the heart and lungs. When a person has Chronic Obstructive Pulmonary Disorder (COPD), a device called an oxygen concentrator can be used to improve quality of life. An oxygen concentrator is an electrically powered device that takes in room air and converts it to an oxygen rich gas mixture suitable for breathing. Although a few models are battery powered, oxygen concentrators are not easily portable because they are bulky and weigh between 25–50 lbs. In this study, components were identified for re design to reduce the overall weight of the device. For instance, the concentrator casing was identified as its heaviest component. Using finite element analysis, changes in wall thickness and dimensions can be investigated to reduce weight while maintaining structural integrity. By reducing the weight of the casing, the oxygen concentrator will be easier to transport.

scholarly journals Finite Element Analysis Study on Lattice Structure Fabricated Using Corn Husk Fibre Reinforced Recycled Polystyrene Composite

2021 ◽  
Vol 335 ◽  
pp. 03011
Author(s):  
Mohammed Shariff Mohamed Sulaiman ◽  
Seong Chun Koay ◽  
Ming Yeng Chan ◽  
Hui Leng Choo ◽  
Ming Meng Pang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Integrity ◽  
Lattice Structure ◽  
Lattice Parameter ◽  
Triangular Prism ◽  
Hexagonal Prism ◽  
Element Analysis ◽  
Corn Husk ◽  
Fea Simulation

This research investigated the lattice structure fabricated using corn husk fibre reinforced recycled polystyrene composite using Finite Element Analysis (FEA). The material’s properties of this composite material were obtained from previous study. Then, the lattice structure of lattice structure was created using Creo® software and the FEA simulation was done by ANSYS software. In this study, the lattice structures were created using triangular prism and hexagonal prism. The analysis was divided into two conditions: 1) lattice structure with different prism shape and similar surface area, 2) lattice structure with varies of strut thickness and 3) lattice structure with different prism shape and similar lattice parameter. The results show the lattice structure with triangular prism have more structural integrity than hexagonal prism. Then, lattice structure with triangular prism can be built with lesser material but stronger and stiffer than lattice structure with hexagonal prism.

A Hybrid Shape Optimization Method Based on Implicit Differentiation and Node Removal Techniques

1993 ◽  
Author(s):  
P. Y. Shim ◽  
S. Mannoochehri
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Optimal Design ◽  
Design Methodology ◽  
Structural Integrity ◽  
Boundary Elements ◽  
Programming Algorithm ◽  
Element Analysis ◽  
Node Removal ◽  
Removal Technique

Abstract This paper presents a hybrid shape optimal design methodology using an implicit differentiation approach for sensitivity analysis and a node removal technique for shape alteration. The approach presented attempts to overcome the weaknesses inherent in each individual technique. The basic idea is to combine the sensitivity analysis, which forms the analytical basis for the algorithm, and a node removal technique, which grossly modifies the shape without the need for a remeshing after each iteration. The sensitivity analysis is based on the finite element equilibrium equation and the implicit differentiation technique. It examines the effect positional changes of the boundary nodes have on the stress values. Using the sensitivity results, a sequential linear programming algorithm is utilized to determine optimum positions of the boundary nodes. These optimization results are provided as inputs to an algorithm that decides which boundary nodes should be removed. By removing boundary nodes, the boundary elements change to either a triangular or a non-existent type. This shape modification procedure starts from the boundary elements and moves toward the internal elements. Only two iterations of finite element analysis are required to modify one boundary layer. To maintain the structural integrity and the connectivity of the elements in the model, a connectivity check is performed after each iteration. Three design examples are given to illustrate the accuracy and the steps involved in the proposed optimal design methodology.

Improved Interaction and Visualization of Finite Element Data for Virtual Prototyping

1997 ◽  
Author(s):  
Helmut Haase ◽  
Thilo Preß
Keyword(s):  
Finite Element ◽  
User Interfaces ◽  
Virtual Prototyping ◽  
Level Of Detail ◽  
Flexible Tool ◽  
Element Analysis ◽  
Quality Of Results ◽  
Element Data ◽  
Element Shape

Abstract This paper discusses the properties of possible virtual prototyping systems using finite element analysis and reports on a prototype implementation of such a system in order to illustrate the concepts. Virtual reality user interfaces will improve some existing applications and lead to new application domains. Several crucial points such as overall system architecture, speed and intuitivity of interaction, and visualization quality of results are identified and possible solutions are suggested. This includes a flexible virtual hand interaction with adjustable finger size. In particular a level of detail technique for finite element data based on element shape functions is presented which can greatly improve visualization quality as compared to common visualization approaches. This level of detail technique provides a flexible tool to adjust the exactness of visualization to rendering time (i.e., degree of interactivity) constrains. The concepts are currently being implemented within a testbed called VEIFEL (Virtual Environment Investigation of Finite ELement data). A report of this work and of resulting experiences is given.

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