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Full-Text Articles in Mechanical Engineering

Geometric Decomposition And Structural Shape Modification For Turbomachinery Blades, Brian D. Hines, James H. Oliver Sep 1994

Geometric Decomposition And Structural Shape Modification For Turbomachinery Blades, Brian D. Hines, James H. Oliver

Mechanical Engineering Conference Presentations, Papers, and Proceedings

An efficient and precise method is presented for the generation of turbomachinery blade models in nominal configuration, i.e., the "cold-shape" given the blade geometry at operating conditions, i.e., the "hot-shape." The shape correction technique has two main components: a preprocessor that generates a plate finite element model of the hot-shape geometry, and postprocessor decomposes the hot-shape blade surface model into a mean camber surface and an associated set of thickness functions. A plate finite element mesh is generated on the resulting mean camber surface. The finite element model is used as input for specialized analysis software for cold-shape ...


Visual Interaction In Acoustic-Structural Analysis Of Automobiles, Vijoy Gaddipati, Judy M. Vance, Richard Devries Sep 1994

Visual Interaction In Acoustic-Structural Analysis Of Automobiles, Vijoy Gaddipati, Judy M. Vance, Richard Devries

Mechanical Engineering Conference Presentations, Papers, and Proceedings

This paper describes a graphical technique used for investigating the effects of structural design changes on the sound pressure levels generated in an automobile compartment. Low frequency noise in the passenger compartment (in approximately the 20-85 Hz frequency range) is of primary interest, and particularly that noise which is generated by the structural vibrations of the wall panels and various other smaller parts of the compartment. A designer faced with reducing the noise levels at various frequencies typically has several hundred design variables as candidates for change. This paper describes a computer interface that facilitates understanding of the effect various ...


Parametric Volume Models For Interactive Three-Dimensional Grid Generation, Jawad D. Mokhtar, James H. Oliver Sep 1994

Parametric Volume Models For Interactive Three-Dimensional Grid Generation, Jawad D. Mokhtar, James H. Oliver

Mechanical Engineering Conference Presentations, Papers, and Proceedings

A methoid based on non-uniform rational B-spline (NURBS) curve, surface, and solid technology is presented for interactive grid generation of three-dimensional flow fields encountered in turbomachinery applications. The method allows construction of several types of mutli-block grids including H-grids for three dimensional grid generation. Automated two-dimensional block construction is facilitated via a traversal method that searches four-sided regions in the initial block structure. A NURBS surface is then constructed on each block by transfinite interpolation of the boundary curves themselves, and various point distribution options may be applied. Three-dimensional grid generation is an extension of the two-dimensional procedure. Tri-parametric hyperpatches ...


Nc Milling Error Assessment And Tool Path Correction, Yunching Huang, James H. Oliver Jul 1994

Nc Milling Error Assessment And Tool Path Correction, Yunching Huang, James H. Oliver

Mechanical Engineering Conference Presentations, Papers, and Proceedings

A system of algorithms is presented for material removal simulation, dimensional error assessment and automated correction of Þve-axis numerically controlled (NC) milling tool paths. The methods are based on a spatial partitioning technique which incorporates incremental proximity calculations between milled and design surfaces. Hence, in addition to real-time animated Þve-axis milling simulation, milling errors are measured and displayed simultaneously. Using intermediate error assessment results, a reduction of intersection volume algorithm is developed to eliminate gouges on the workpiece via tool path correction. Finally, the view dependency typical of previous spatial partitioning-based NC simulation methods is overcome by a contour display ...


A Fringe Center Detection Technique Based On A Sub-Pixel Resolution, And Its Applications Using Sinusoidal Gratings, Ming Chang, Paul P. Lin, Wen Chih Tai Jan 1994

A Fringe Center Detection Technique Based On A Sub-Pixel Resolution, And Its Applications Using Sinusoidal Gratings, Ming Chang, Paul P. Lin, Wen Chih Tai

Mechanical Engineering Faculty Publications

A common problem in optical profilometry is the accuracy in locating fringe centers. This paper presents an accurate fringe center detection technique based on sub-pixel resolution using the fringe projection method. An optimum reconstruction filter is developed which has low sensitivity to noise. In fringe center detection, computer simulation results of using one-pixel and sub-pixel resolutions are compared. The detection technique is then applied to radius measurement of cylindrical objects and surface profile measurement of diffuse objects. The experimental results thus obtained through the proposed optimum reconstruction filter show significant improvement in measurement accuracy.


On The Evolution Of Cae Research, Clive L. Dym, Raymond E. Levitt Jan 1994

On The Evolution Of Cae Research, Clive L. Dym, Raymond E. Levitt

All HMC Faculty Publications and Research

Less than a decade ago it seemed that a new paradigm of engineering–called computer-aided engineering (CAE) – was emerging. This emergence was driven in part by the success of computer support for the tasks of engineering analysis and in part by a new understanding of how computational ideas largely rooted in artificial intelligence (AI) could perhaps improve the practice of engineering, especially in the area of design synthesis. However, while this “revolution” has failed to take root or flourish as a separate discipline, it has spawned research that is very different from traditional engineering research. To the extent that such ...