scholarly journals A 3-D Model for a Multilayered Body Loaded Normally and Tangentially Against a Rigid Body: Application to Specific Coatings

1998 ◽  
Vol 120 (4) ◽  
pp. 668-676 ◽  
Author(s):  
S. Plumet ◽  
M.-C. Dubourg
Keyword(s):  
Rigid Body ◽  
Three Dimensional ◽  
Integral Transforms ◽  
Internal Stresses ◽  
Three Dimensional Model ◽  
Linear Elasticity Theory ◽  
Contact Conditions ◽  
Multilayered Body ◽  
Potential Failure ◽  
D Model

Coatings are increasingly used to improve the mechanical and tribological behavior of surfaces. It is necessary to develop models to guide the initial choice of coating/substrate combinations that can withstand the applied loads. A three-dimensional model of an elastic multilayered body, loaded both normally and tangentially against an elliptical rigid body (partial sliding, rolling/sliding conditions), is presented here. This model is based on linear elasticity theory, integral transforms, Fast Fourier Transform, and unilateral contact analysis with friction. Normal and tangential contact conditions between the two bodies are first determined and then used to calculate the multilayered body stress field. One application is given here: The influence of the mechanical properties of coating and substrate, as well as coating thickness, is studied on contact conditions, internal stresses, and potential failure mechanisms.

3-D Model of Proton Exchange Membrane Fuel Cells

2000 ◽  
Author(s):  
Tianhong Zhou ◽  
Hongtan Liu
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Three Dimensional Model ◽  
Chemical Reaction Kinetics ◽  
Fuel Cell Performance ◽  
D Model

Abstract A comprehensive three-dimensional model for a proton exchanger membrane (PEM) fuel cell is developed to evaluate the effects of various design and operating parameters on fuel cell performance. The geometrical model includes two distinct flow channels separated by the membrane and electrode assembly (MEA). This model is developed by coupling the governing equations for reactant mass transport and chemical reaction kinetics. To facilitate the numerical solution, the full PEM fuel cell was divided into three coupled domains according to the flow characteristics. The 3-D model has been applied to study species transport, heat transfer, and current density distributions within a fuel cell. The predicated polarization behavior is shown to compare well with experimental data from the literature. The modeling results demonstrate good potential for this computational model to be used in operation simulation as well as design optimization.

scholarly journals A cross-validated three-dimensional model of an englacial and subglacial drainage system in a High-Arctic glacier

2020 ◽  
Vol 66 (256) ◽  
pp. 278-290
Author(s):  
Lena U. Hansen ◽  
Jan A. Piotrowski ◽  
Douglas I. Benn ◽  
Heidi Sevestre
Keyword(s):  
Three Dimensional ◽  
Drainage System ◽  
High Arctic ◽  
Water Drainage ◽  
Three Dimensional Model ◽  
Closure Mechanism ◽  
Ground Penetrating ◽  
Arctic Glacier ◽  
D Model ◽  
Englacial Drainage

AbstractRecent speleological surveys of meltwater drainage systems in cold and polythermal glaciers have documented dynamic englacial and in some cases subglacial conduits formed by the ‘cut-and-closure’ mechanism. Investigations of the spatial distribution of such conduits often require a combination of different methods. Here, we studied the englacial drainage system in the cold glacier Longyearbreen, Svalbard by combining speleological exploration of a 478 m long meltwater conduit with a high-resolution ground penetrating radar (GPR) survey with two different centre-frequencies (25 and 100 MHz). The results yielded a 3-D documentation of the present englacial drainage system. The study shows that the overall form of englacial conduits can be detected from velocity−depth converted GPR data, and that the 3-D model can facilitate a method to pinpoint the reflections in a radargram corresponding with the englacial drainage system, although fine detail cannot be resolved. Visible reflections approximately parallel to the mapped englacial water drainage system likely result from sediment incorporated in the ice or from abandoned parts of the englacial drainage system.

Three-Dimensional Catalytic Regeneration Modeling of SiC Diesel Particulate Filters

2005 ◽  
Vol 128 (2) ◽  
pp. 421-433 ◽  
Author(s):  
George Pontikakis ◽  
Anastassios Stamatelos
Keyword(s):  
Three Dimensional ◽  
Particulate Filter ◽  
Particulate Emissions ◽  
Three Dimensional Model ◽  
Standard Equipment ◽  
Efficient System ◽  
Diesel Particulate ◽  
Filter Performance ◽  
D Model ◽  
Diesel Filter

Increasingly stringent diesel particulate emissions standards have reestablished international interest in diesel filters, whose first series application dates back to 1985. Modern diesel engine technology, with computerized engine management systems and advanced, common rail injection systems, needs to be fully exploited to support efficient and durable diesel filter systems with catalytic aids, as standard equipment in passenger cars. Efficient system and components’ optimization requires the use of mathematical models of diesel filter performance. The three-dimensional model for the regeneration of the diesel particulate filter presented in this paper has been developed as an engineering tool for the detailed design optimization of SiC diesel filters of modular structure. The 3-D modeling is achieved by interfacing an existing 1-D model to commercial finite element method software for the computation of the 3-D temperature field within the whole filter assembly, including the adhesive of the filter blocks, the insulation mat, and the metal canning. The 3-D model is applied to real-world component optimization studies of diesel filter systems.

The Three-Dimensional Model for a Community

2022 ◽  
pp. 521-534
Author(s):  
Gregory B. White ◽  
Natalie Sjelin
Keyword(s):  
Cyber Security ◽  
Action Plan ◽  
Three Dimensional ◽  
Maturity Model ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Initial Development ◽  
The Creation ◽  
D Model

The community cyber security maturity model (CCSMM) was designed and developed to provide communities with an action plan to build a viable and sustainable cybersecurity program focused on improving their overall cybersecurity capability. Not long after the initial development of the model, it was realized that there are intertwined relationships that needed to be addressed. This drove the creation of the three-dimensional model broadening the scope to include individuals, organizations, communities, states, and the nation. This chapter will provide an overview of the development and importance of the 3-D model and will describe the scope areas that were included.

Evaluation of an approximate method for incorporating floating docks in harbor wave prediction models

2005 ◽  
Vol 32 (6) ◽  
pp. 1082-1092 ◽  
Author(s):  
Dongcheng Li ◽  
Vijay Panchang ◽  
Zhaoxiang Tang ◽  
Zeki Demirbilek ◽  
Jerry Ramsden
Keyword(s):  
Prediction Models ◽  
Three Dimensional ◽  
Wave Model ◽  
Three Dimensional Model ◽  
Transmission Coefficients ◽  
Mild Slope Equation ◽  
Wide Range ◽  
Floating Objects ◽  
Floating Breakwaters ◽  
D Model

Computer models based on the two-dimensional (2-D) elliptic mild-slope equation are nowadays routinely used in harbor engineering applications. However, structures like floating breakwaters and docks, which are often encountered in the modeling domain, render the problem for locally three-dimensional model and hence are problematic to incorporate in a 2-D model. Tsay and Liu (Applied Ocean Research. 1983. Vol 5(1): 30–37) proposed a highly simplified but approximate approach that does not violate the overall two dimensionality of the problem. The validity of their approach is examined in detail, and it is found that although their approximation provides results with the correct trend, the actual solutions deviate considerably from the theoretical solutions. We have developed correction factors that may be used to produce more reliable results using the framework of Tsay and Liu. Application of the resulting method to a harbor in Alaska shows that docks in the harbor distort the wave field considerably and create a reflective pattern that has the potential to affect navigation safety in some areas. A by-product of this paper consists of plots of transmission coefficients for waves propagating past rectangular and cylindrical floating objects of infinite extent for a wide range of conditions encountered in practice. Such transmission coefficients are at present readily available in the published literature for selected cases only.Key words: wave, model, mild slope, equation, floating breakwater, dock, marina, harbor.

scholarly journals Digital Documentation and a 3-D Model of Beaufort Castle via RTK GNSS, Terrestrial Laser Scanner and UAS-based Photogrammetry

2021 ◽  
Vol 310 ◽  
pp. 05002
Author(s):  
Yousef Naanouh ◽  
Vasyutinskaya Stanislava
Keyword(s):  
Laser Scanning ◽  
3D Model ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Terrestrial Laser Scanning ◽  
Three Dimensional Model ◽  
South Lebanon ◽  
Aerial Vehicle ◽  
Digital Documentation ◽  
D Model

Three-dimensional digital technology is important in the maintenance and monitoring of archeological sites. This paper focuses on using a combination of terrestrial laser scanning and unmanned aerial vehicle (Phantom 4 pro) photogrammetry to establish a three-dimensional model and associated digital documentation of Beaufort castle (Arnoun, South Lebanon). The overall discrepancy between the two technologies was sufficient for the generation of convergent data. Thus, the terrestrial laser scanning and phantom 4 photogrammetry data were aligned and merged post-conversion into compatible extensions. A three-D dimensional (3D) model, with planar and perpendicular geometries, based on the hybrid datapoint cloud was developed. This study demonstrates the potential of using the integration of terrestrial laser scanning and photogrammetry in 3D digital documentation and spatial analysis of the Lebanese archeological sites.

Dynamic Analysis of Rigid-Body Mechanisms Mounted on Flexible Support Structures — Planar Case

2006 ◽  
Vol 505-507 ◽  
pp. 589-594 ◽  
Author(s):  
Huai Ku Sun ◽  
Cun Gin Chen ◽  
Yu Chen Shen
Keyword(s):  
Rigid Body ◽  
Dynamic Analysis ◽  
Flexible Structures ◽  
Three Dimensional ◽  
Support Structures ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Planar Case ◽  
Flexible Support ◽  
Future Work

Computer-aided analysis of rigid-body mechanisms is combined with the finite element analysis of flexible structures to develop a computer model and derive the equation of motion, incorporating the Lagrange multiplier, to be used in the dynamic analysis of multi-rigid-body mechanisms mounted on flexible support structures. The resulting equations are solved by numerical integration. Predicting and analyzing the performance of the full system, including the motion of the system components and the forcing condition, during the engineering design process will promote the success of the entire system. Finally, a machine gun system with a flexible mount is given as a numerical example. The results reveal that the interaction between the rigid-body mechanisms and its flexible support structures importantly determines the performance of whole system. This study considers only the planar case. Our future work will propose a more complicated fully three-dimensional model.

A Three-Dimensional Rigid-Body Model for Seismic Analysis of the Pebble-Bed HTR Graphite Core Structure

2013 ◽  
Author(s):  
Chuan Zeng ◽  
Haitao Wang
Keyword(s):  
Rigid Body ◽  
Degrees Of Freedom ◽  
Structural Integrity ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Computer Code ◽  
Seismic Load ◽  
Three Dimensional Model ◽  
Pebble Bed ◽  
Rigid Body Model

Graphite plays an important role in the pebble-bed high temperature gas-cooled reactors (HTR) as moderator, reflector as well as internal structural material. The HTR core consists of a large number of graphite bricks interconnected with keys. It is required that the structural integrity of the HTR core be maintained when subjected to the seismic load. Hence it is important from the viewpoint of seismic design to investigate the seismic responses of the graphite bricks. Considering the pebble-bed HTR has various graphite shapes, a generalized three-dimensional model with the associated computer code is developed to treat these interconnected graphite bricks with arbitrary shapes. In this model, each brick is treated as a rigid body with six degrees-of-freedom: three translational displacements and three rotations around the brick center of gravity. A nonlinear spring dashpot model is applied to present the collision between adjacent bricks and the interaction forces through the key systems. In the numerical tests, the code is verified by comparing predicted responses with exact solutions for two cases and good agreement is observed. The model is then used for the dynamic analysis of the side reflectors of the pebble-bed HTR core under a given seismic load. The calculated response behaviour of the side reflector column is summarized and discussed.

A three-dimensional model for bolted connections in wood

2003 ◽  
Vol 30 (3) ◽  
pp. 555-567 ◽  
Author(s):  
D M Moses ◽  
H G.L Prion
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Douglas Fir ◽  
Recent Criticism ◽  
Three Dimensional Model ◽  
Anisotropic Plasticity ◽  
Weakest Link ◽  
Modes Of Failure ◽  
Bolt Connection ◽  
D Model

Recent criticism of the bolted connection requirements in the Canadian wood design code CSA Standard O86 indicates that the code lacks consideration of the different modes of failure, particularly as they relate to multiple-bolt connections. A finite element model is proposed to predict load–displacement behaviour, stress distributions, ultimate strength, and mode of failure in single- and multiple-bolt connections. The three-dimensional (3-D) model uses anisotropic plasticity for the wood member and elastoplasticity for the bolt. The Weibull weakest link theory is used to predict failure at given levels of probability. Predictions for connection behaviour in Douglas-fir and laminated strand lumber (LSL) correspond to experimentally observed behaviour. The output from the 3-D model is used for a multiple-bolt connection spring model to illustrate many of the phenomena described in the literature.Key words: bolt, Douglas-fir, connection, model, plasticity, weakest link, wood.

The Three-Dimensional Model for a Community

2021 ◽  
pp. 55-74
Keyword(s):  
Cyber Security ◽  
Action Plan ◽  
Three Dimensional ◽  
Maturity Model ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Initial Development ◽  
The Creation ◽  
D Model

The community cyber security maturity model (CCSMM) was designed and developed to provide communities with an action plan to build a viable and sustainable cybersecurity program focused on improving their overall cybersecurity capability. Not long after the initial development of the model, it was realized that there are intertwined relationships that needed to be addressed. This drove the creation of the three-dimensional model broadening the scope to include individuals, organizations, communities, states, and the nation. This chapter will provide an overview of the development and importance of the 3-D model and will describe the scope areas that were included.

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