Design and Deformation of CAD Surface Models With Haptics

2004 ◽  
Author(s):  
X. Liu ◽  
G. Dodds ◽  
J. McCartney ◽  
B. K. Hinds
Keyword(s):  
Shape Control ◽  
Force Feedback ◽  
Complex Geometry ◽  
Virtual Space ◽  
Cad Model ◽  
Two Dimensional ◽  
Shape Functions ◽  
Ship Hulls ◽  
Control Functions ◽  
Surface Models

With traditional two-dimensional based interfaces, many CAD surface models, such as automobile bodies and ship hulls, are difficult to design and edit due to their 3D nature. This paper discusses the haptic-based deformation for the design of CAD surface models. With haptic devices (force feedback interfaces) designers can, in virtual space, touch a native B-rep CAD model, and use their tactile senses to manipulate it by pushing, pulling and dragging its surfaces in a natural 3D environment. The paper presents shape control functions. By using the shape functions, designers can directly manipulate and deform a selected region of a surface to the desired shape, and generate complex geometry with simple operations. Force feedback gives designers the greatest flexibility for the design of complex surfaces.

scholarly journals Laser Scanning Ship Hulls to Support Hydrodynamic Simulations

2021 ◽  
Author(s):  
Tamás Lovas ◽  
Árpád József Somogyi ◽  
Győző Simongáti
Keyword(s):  
Laser Scanning ◽  
Complex Geometry ◽  
Terrestrial Laser Scanning ◽  
Point Clouds ◽  
Resource Analysis ◽  
Hydrodynamic Simulations ◽  
Ship Hulls ◽  
Surface Models ◽  
Processing Procedure ◽  
Effective Technology

Terrestrial laser scanning is an effective technology to capture high density and accurate point clouds about objects with complex geometry. Ship industry requires 3D hull models for multiple reverse engineering purposes; renovation, as-built analysis, simulations etc. The paper discusses how terrestrial laser scanning can be applied to capture ship hull geometry to support hydrodynamic simulations. It presents recommendations of survey geometry and methods considering scanner locations, reflectivity issues. Hydrodynamic simulations require specific types of surface models as inputs; data processing procedure is discussed how the point clouds are effectively transformed to models to be applied. Resource analysis is also included, such as duration of survey and processing, equipment to be used.

Manipulation of CAD surface models with haptics based on shape control functions

2005 ◽  
Vol 37 (14) ◽  
pp. 1447-1458 ◽  
Author(s):  
X. Liu ◽  
G. Dodds ◽  
J. McCartney ◽  
B.K. Hinds
Keyword(s):  
Shape Control ◽  
Control Functions ◽  
Surface Models

Comparison of DSMC and CFD Models of Heat Transfer in a Rarefied Two-Dimensional Geometry

2018 ◽  
Author(s):  
Dilesh Maharjan ◽  
Mustafa Hadj-Nacer ◽  
Miles Greiner ◽  
Stefan K. Stefanov
Keyword(s):  
Heat Transfer ◽  
Rarefied Gas ◽  
Complex Geometry ◽  
Direct Simulation Monte Carlo ◽  
Accurate Method ◽  
Vacuum Drying ◽  
Helium Pressure ◽  
Two Dimensional ◽  
Dsmc Method ◽  
Cfd Simulations

During vacuum drying of used nuclear fuel (UNF) canisters, helium pressure is reduced to as low as 67 Pa to promote evaporation and removal of remaining water after draining process. At such low pressure, and considering the dimensions of the system, helium is mildly rarefied, which induces a thermal-resistance temperature-jump at gas–solid interfaces that contributes to the increase of cladding temperature. It is important to maintain the temperature of the cladding below roughly 400 °C to avoid radial hydride formation, which may cause cladding embrittlement during transportation and long-term storage. Direct Simulation Monte Carlo (DSMC) method is an accurate method to predict heat transfer and temperature under rarefied condition. However, it is not convenient for complex geometry like a UNF canister. Computational Fluid Dynamics (CFD) simulations are more convenient to apply but their accuracy for rarefied condition are not well established. This work seeks to validate the use of CFD simulations to model heat transfer through rarefied gas in simple two-dimensional geometry by comparing the results to the more accurate DSMC method. The geometry consists of a circular fuel rod centered inside a square cross-section enclosure filled with rarefied helium. The validated CFD model will be used later to accurately estimate the temperature of an UNF canister subjected to vacuum drying condition.

Comparison principles for free-surface flows with gravity

1991 ◽  
Vol 230 ◽  
pp. 231-243 ◽  
Author(s):  
Walter Craig ◽  
Peter Sternberg
Keyword(s):  
Solitary Waves ◽  
Finite Depth ◽  
Free Surface Flows ◽  
Immiscible Fluids ◽  
Steady Flows ◽  
Two Dimensional ◽  
Surface Flows ◽  
Ship Hulls ◽  
Geometrical Information ◽  
Supercritical Flows

This article considers certain two-dimensional, irrotational, steady flows in fluid regions of finite depth and infinite horizontal extent. Geometrical information about these flows and their singularities is obtained, using a variant of a classical comparison principle. The results are applied to three types of problems: (i) supercritical solitary waves carrying planing surfaces or surfboards, (ii) supercritical flows past ship hulls and (iii) supercritical interfacial solitary waves in systems consisting of two immiscible fluids.

Implementation of p and h-p Versions of the Finite Element Method

1992 ◽  
Author(s):  
Ye-Chen Lai ◽  
Timothy C. S. Liang ◽  
Zhenxue Jia
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Analysis ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Shape Functions ◽  
Linear Elastic ◽  
Finite Element Software ◽  
Analysis Process ◽  
Adaptive Analysis

Abstract Based on hierarchic shape functions and an effective convergence procedure, the p-version and h-p adaptive analysis capabilities were incorporated into a finite element software system, called COSMOS/M. The range of the polynomial orders can be varied from 1 to 10 for two dimensional linear elastic analysis. In the h-p adaptive analysis process, a refined mesh are first achieved via adaptive h-refinement. The p-refinement is then added on to the h-version designed mesh by uniformly increasing the degree of the polynomials. Some numerical results computed by COSMOS/M are presented to illustrate the performance of these p and h-p analysis capabilities.

Haptic Display of Interaction Forces in MEMS Assembly Processes

2000 ◽  
Author(s):  
Daniel J. Evans ◽  
Sankar Jayaram ◽  
John T. Feddema ◽  
Uma Jayaram ◽  
William A. Johnson ◽  
...  
Keyword(s):  
Boundary Element ◽  
Force Feedback ◽  
Complex Geometry ◽  
Mechanical Systems ◽  
Contact Forces ◽  
Haptic Display ◽  
Electrostatic Forces ◽  
Monolithic Integrated Circuit ◽  
Micro Electro Mechanical Systems ◽  
Human Scale

Abstract In recent years, the world economy has seen expansive market growth in the area of Micro-Electro Mechanical Systems (MEMS). It is predicted that the MEMS market could reach more than $34 billion by the year 2002. Today, commercially available MEMS products include accelerometers for airbags and inkjet printer heads. These products require little or no assembly because a monolithic integrated circuit process is used to develop the devices. However, future MEMS will be more elaborate. Monolithic integration is not feasible when incompatible processes, complex geometry, or different materials are involved. For these cases, new and extremely precise micro-manipulation capabilities will be required for successful product realization. This paper outlines the design and implementation of a computer aided simulation of Micro Electro Mechanical Systems (MEMS) assembly utilizing force feedback devices for display of forces of interaction. The system described in this paper solves boundary element equations for electrostatic forces between MEMS components and then displays this solution in near real time with the help of the PHANToM force feedback device. Issues discussed in this paper include: boundary element solutions of electrostatic forces, interpolation of a six degree of freedom solution grid, scaling up of electrostatic forces to human scale, and use of the PHANToM device for haptic display of electrostatic and contact forces.

Transient Flow Field on Containment Floor Predicted by Two-Dimensional Shallow Equation Solver

2009 ◽  
Author(s):  
Young Seok Bang ◽  
Gil-Soo Lee ◽  
Byung-Gil Huh ◽  
Deog-Yeon Oh ◽  
Sweng-Woong Woo
Keyword(s):  
Flow Field ◽  
Transient Flow ◽  
Complex Geometry ◽  
Solid Wall ◽  
Shallow Water Equation ◽  
Water Reservoir ◽  
Two Dimensional ◽  
Pressurized Water ◽  
Fast Running ◽  
Propagation Of Waves

For the analysis of debris transport on containment floor, a model to predict the flow field should have a fast-running capability and high accuracy. A model is developed to calculate the transient flow field on the containment floor involving a complex geometry in the advanced pressurized water reactor (PWR) such as Advanced Power Reactor (APR)-1400, which does not have a switchover from injection to recirculation following a loss-of-coolant accident (LOCA). Two-dimensional shallow water equation (SWE) is solved using the finite volume method (FVM). Unstructured triangular meshes are used to simulate the complex structures on the containment floor. Harten-Lax-van Leer (HLL) scheme, one of the approximate Riemann solver, is adopted to capture the dry-wet interface and to determine the momentum flux at the interface. An experiment of a sudden dam break having water reservoir and L-shape open channel is simulated and compared with the calculated result, which supports the validity of the present model. The model is also applied to calculation of the flow field of APR-1400. The calculated flow field can be characterized by the propagation of waves generated by surface level difference and by the reflection of waves from solid wall. The transient flow rates entering to the Holdup Volume Tank (HVT) can be predicted within a practical limit of computational resource.

A Coupled FE-Meshfree Triangular Element for Acoustic Radiation Problems

2020 ◽  
pp. 2041002
Author(s):  
Wei Li ◽  
Qifan Zhang ◽  
Qiang Gui ◽  
Yingbin Chai
Keyword(s):  
Acoustic Radiation ◽  
Interpolation Method ◽  
Partition Of Unity ◽  
Local Approximation ◽  
Triangular Element ◽  
Two Dimensional ◽  
Shape Functions ◽  
Radial Point Interpolation ◽  
Point Interpolation Method ◽  
Point Interpolation

To improve the accuracy of the standard finite element (FE) solutions for acoustic radiation computation, this work presents the coupling of a radial point interpolation method (RPIM) with the standard FEM based on triangular (T3) mesh to give a coupled “FE-Meshfree” Trig3-RPIM element for two-dimensional acoustic radiation problems. In this coupled Trig3-RPIM element, the local approximation (LA) is represented by the polynomial-radial basis functions and the partition of unity (PU) concept is satisfied using the standard FEM shape functions. Incorporating the present coupled Trig3-RPIM element with the appropriate non-reflecting boundary condition, the two-dimensional acoustic radiation problems in exterior unbounded domain can be successfully solved. The numerical results demonstrate that the present coupled Trig3-RPIM have significant superiorities over the standard FEM and can be regarded as a competitive numerical techniques for exterior acoustic computation.

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