Computer Simulation of Three-Dimensional Mechanical Assemblies: Part II — Computer Simulation

Author(s):  
T. C. Chou ◽  
F. W. Liou

Abstract Computer simulation of the kinematic and dynamic behaviors of mechanical assemblies has become a very important tool in design and manufacturing, because the designer can foresee how a product is going to perform before the product is actually fabricated. However, up to now, the most current simulation modules are based on analysis from another kinematic or dynamic module by specifying the mating conditions between components, and then displaying the motion on the screen. This computer simulation actually performs similarly to a movie, and can only provide visual checking. The drawback of this simulation approach is that designers are forced to use the available joint models, and may lose their creativity. In part I of this paper, general mathematical modeling of the multi-body system is presented, while part II of this paper, a prototype convex-feature modeling system is presented with which a designer can interactively create an assembly of mechanical components ready for dynamic analysis. It can provide a state-of-the-art technology for real simulation of any mechanical systems, and act as a cost-effective test bed for concepts, final design, and control algorithms.

Author(s):  
Yong Fang ◽  
F. W. Liou

Abstract In Part I of this paper, a dynamic modeling system for the simulation of three dimensional mechanical assemblies is presented. With this simulation tool, a designer can interactively create an assembly of mechanical components ready for dynamic analysis. The modeling system presented in this paper includes the derivation of the equations of motion of spatial multi-body systems, and the formulation of the equations to model the associated collision detection and collision responses. Part II of this paper is to introduce the geometry modeling and computer simulation of 3D systems.


Author(s):  
Zipeng Guo ◽  
Lu An ◽  
Sushil Lakshmanan ◽  
Jason Armstrong ◽  
Shenqiang Ren ◽  
...  

Abstract The macro-porous ceramics has promising durability and thermal insulation performance. As porous ceramics find more and more applications across many industries, a cost-effective and scalable additive manufacturing technique for fabricating macro-porous ceramics is highly desirable. Herein, we reported a facile additive manufacturing approach to fabricate porous ceramics and control the printed porosity. Several printable ceramic inks were prepared, the foaming agent was added to generate gaseous bubbles in the ink, followed by the direct ink writing and the ambient-pressure and room-temperature drying to create the three-dimensional geometries. A set of experimental studies were performed to optimize the printing quality. The results revealed the optimal process parameters for printing the foamed ceramic ink with a high spatial resolution and fine surface quality. Varying the concentration of the foaming agent enables the controllability of the structural porosity. The maximum porosity can reach 85%, with a crack-free internal porous structure. The tensile tests showed that the printed macro-porous ceramics possessed enhanced durability with the addition of fiber. With a high-fidelity 3D printing process and the precise controllability of the porosity, we showed that the printed samples exhibited a remarkably low thermal conductivity and durable mechanical strength.


Author(s):  
Yong Fang ◽  
F. W. Liou

Abstract In this paper, the implementation of a modeling system for the simulation of three dimensional mechanical assemblies with elastic components is presented. A mechanical assembly is modeled as a multi-body system with changing topologies. The elastic behavior can be automatically modeled using finite element method. With this simulation tool, a designer can interactively create an assembly of mechanical components ready for dynamic and elastic analysis. This paper presents a prototype of the modeling system.


Author(s):  
F. Salaun ◽  
D. R. Novog

The Canadian supercritical water-cooled reactor (SCWR) design is part of Canada's Generation IV reactor development program. The reactor uses batch fueling, light water above the thermodynamic critical point as a coolant and a heavy water moderator. The design has evolved considerably and is currently at the conceptual design level. As a result of batch fueling, a certain amount of excess reactivity is loaded at the beginning of each fueling cycle. This excess reactivity must be controlled using a combination of burnable neutron poisons in the fuel, moderator poisons, and control blades interspersed in the heavy water moderator. Recent studies have shown that the combination of power density, high coolant temperatures, and reactivity management can lead to high maximum cladding surface temperatures (MCST) and maximum fuel centerline temperatures (MFCLT) in this design. This study focuses on improving both the MCST and the MFCLT through modifications of the conceptual design including changes from a 3 to 4 batch fueling cycle, a slightly shortened fuel cycle (although exit burnup remains the same), axial graded fuel enrichment, fuel-integrated burnable neutron absorbers, lower reactivity control blades, and lower reactor thermal powers as compared to the original conceptual design. The optimal blade positions throughout the fuel cycle were determined so as to minimize the MCST and MFCLT using a genetic algorithm and the reactor physics code PARCS. The final design was analyzed using a fully coupled PARCS-RELAP5/SCDAPSIM/MOD4.0 model to accurately predict the MCST as a function of time during a fueling cycle.


2020 ◽  
Vol 2020 (3) ◽  
pp. 60408-1-60408-10
Author(s):  
Kenly Maldonado ◽  
Steve Simske

The principal objective of this research is to create a system that is quickly deployable, scalable, adaptable, and intelligent and provides cost-effective surveillance, both locally and globally. The intelligent surveillance system should be capable of rapid implementation to track (monitor) sensitive materials, i.e., radioactive or weapons stockpiles and person(s) within rooms, buildings, and/or areas in order to predict potential incidents proactively (versus reactively) through intelligence, locally and globally. The system will incorporate a combination of electronic systems that include commercial and modifiable off-the-shelf microcomputers to create a microcomputer cluster which acts as a mini supercomputer which leverages real-time data feed if a potential threat is present. Through programming, software, and intelligence (artificial intelligence, machine learning, and neural networks), the system should be capable of monitoring, tracking, and warning (communicating) the system observer operations (command and control) within a few minutes when sensitive materials are at potential risk for loss. The potential customer is government agencies looking to control sensitive materials and/or items in developing world markets intelligently, economically, and quickly.


2020 ◽  
Vol 11 (SPL1) ◽  
pp. 716-722
Author(s):  
Sneha Dhakite ◽  
Sadhana Misar Wajpeyi

The “Coronavirus disease 19 (COVID-19)” is caused by “Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)”, a newly discovered member of the Coronaviridae family of viruses which is a highly communicable. There is no effective medical treatment till date for Coronavirus disease hence prevention is the best way to keep disease away. Rasayana proved to be highly efficacious and cost effective for the Prevention and Control of viral infections when vaccines and standard therapies are lacking. Rasayana Chikitsa is one of the eight branches of Ashtanga Ayurveda which helps to maintain healthy life style. Rasayana improves immunity and performs many vital functions of human body. Vyadhikshamatva that is immune mechanism of the body is involved in Prevention of the occurrence of a new disease and it also decreases the virulence and progression of an existing disease. In COVID-19 the Respiratory system mainly get affected which is evident from its symptoms like cold, cough and breathlessness. Here the drugs help in enhancing immune system and strengthening functions of Respiratory system can be useful. For this purpose, the Rasayana like Chyavanprasha, Agastya Haritaki, Pippali Rasayana, Guduchi, Yashtimadhu, Haridra, Ashwagandha, Tulsi are used. Rasayana working on Respiratory system are best for Prevention of Coronavirus and boosting immune system. Rasayana Chikitsa can be effective in the Prevention as well as reducing symptoms of COVID-19.


2020 ◽  
Author(s):  
Jagjit S Soar

he current COVID-19 pandemic now believed to be based on the mutation of the SARS-CoV virus (first reported in 2002) to SARS-CoV-2 emerging in 2019, is naturally causing extreme worry and concern around the world with sometimes mixed and incoherent messages on how to deal with it. There is a plethora of information from previous epidemics caused by other coronaviruses such as severe acute respiratory syndrome, SARS (2002) and Middle East respiratory syndrome MERS (2012) from which we can extrapolate guidance on how to deal with the current pandemic. In the current absence of specific pharmaceutical agents, we propose assessing the extended tools that we already possess in our biological armoury to combat, prevent and control the spread of this virus. Using a set of precise criteria to locate such possible contenders, we conducted literature searches to find compounds that met these criteria. We have now reduced this to a shortlist of three agents that may be the best candidates. We propose vitamin C, vitamin D and Curcumin fit our criteria well. These compounds are widely available to the general public. They are available online and over-the-counter as supplements. Otherwise healthy individuals are safely able to self-administer these agents as a prophylactic to protect themselves and to enhance their immune response. This would be especially desirable for the elderly and at risk groups. These agents can also be used as adjunct therapy, particularly for those who may have early symptoms. This preventative therapy could be implemented whilst awaiting specific pharmaceutical drugs to emerge as a treatment for COVID-19. Our suggested compounds are a highly cost-effective way to potentially reduce the mortality that is regretfully mounting as a result of COVID-19 infection. The biological mode of action and the dosing of these compounds are summarised.


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