Geometric Modeling Approach Research Articles

A function-based geometric modeling approach for preliminary design.

A function-based geometric modeling approach for preliminary design is developed using an object-oriented programming technique. Preliminary design of engineering systems such as ships and aircraft is a process finding a design object which satisfies several required functions. In the process, it is important to support designers so as to manipulate design objects flexibly. Moreover, it is necessary to manipulate geometries of design entities in order to evaluate their, functions. In this paper, we propose a modeling method of these design objects and their geometry. The system cooperates with both the modeling subsystem of design entities and design parameters, and the geometric modeling subsystem. In the system, each modeling element is represented as an object using an object-oriented programming technique. The procedures for modeling elements are carried out by the methods defined in classes in an autonomous fashion, and geometries are automatically generated with the procedures which are defined in objects of design entities. This approach is effective and helpful in representing design knowledge and supporting the designer's manipulation of design objects. Finally, the prototype system implemented with the method is applied to the preliminary design of a ship's hull arrangement to confirm its validity and effectiveness.

Matrix Analysis Method for Direct and Multiple Contact Multibody Systems

A generalized modeling procedure for curves and surfaces in direct contact relative motions is developed, such that these joints can be consistently included in the well-developed and established (4 × 4) matrix method for kinematic, static, and dynamic analyses of geometrically constrained lower paired multibody mechanical systems. The modeling procedure allows both the analytical and the discretized Geometric Modeling approaches. As one application of these analytical techniques, a numerical procedure for mobility analysis of multiple contact joints is presented and illustrated. Other applications of this development are enumerated.

OYSTER: A Study of Integrated Circuits as Three-Dimensional Structures

This paper presents a design for a software system (OYSTER) for the parametric simulation and analysis of the fabrication steps of very large scale integrated circuit devices. The system is based on a solid geometric modeling approach in which the component parts of an integrated circuit are represented at any step as three-dimensional solid objects in a geometric data base. The simulation of a fabrication step transforms the data base representation of the geometry and the relations among component parts from their state before the step to their state after the step. At any step, and particularly after the final step, the component parts may be analyzed automatically to determine geometric, mechanical, thermal, and electrical properties. Statistical effects may be incorporated to allow investigation of alignment tolerance build-up and yield. A prototype study is described in which an existing geometric modeling system is used to transform a set of planar masks for an FET device through 28 process steps into 3-D models which are used to compute device capacitances.