scholarly journals COMPACT - A Surface Representation Scheme

1988 ◽  
Author(s):  
P. Grossman
Keyword(s):  
Surface Representation ◽  
Representation Scheme

Draping 2D Patterns Onto 3D Surfaces

2003 ◽  
Author(s):  
Ajay Joneja ◽  
Angela Tam ◽  
Fu Jing
Keyword(s):  
Mold Surface ◽  
Polygonal Approximation ◽  
Surface Representation ◽  
B Splines ◽  
3D Surface ◽  
Software Program ◽  
2D Pattern ◽  
Representation Scheme ◽  
3D Surfaces

We describe a simple new CAD operator that allows draping of given 2D patterns onto the surface of a 3D mold. The 2D pattern is any closed, connected polygon or a polygonal approximation of a shape bounded by curves. The mold is typically described in terms of any standard surface representation scheme, such as NURBS or B-Splines. The draping is achieved by mapping skeletal lines on the 2D pattern onto corresponding geodesic curves on the 3D surface. If the mold surface is developable, our method gives a draping with zero distortion. A useful application in the CAD of footwear is demonstrated as a motivation for this work. A simple software program has been implemented to test the operator, and examples are provided to demonstrate its use.

Life-Cycle Engineering Design

1995 ◽  
Vol 117 (B) ◽  
pp. 42-47 ◽  
Author(s):  
K. Ishii
Keyword(s):  
Life Cycle ◽  
Product Life Cycle ◽  
Functional Performance ◽  
Semantic Network ◽  
Research Issues ◽  
Life Cycle Engineering ◽  
Engineering Research ◽  
Design Representation ◽  
Life Cycle Design ◽  
Representation Scheme

Life-cycle engineering seeks to incorporate various product life-cycle values into the early stages of design. These values include functional performance, manufacturability, serviceability, and environmental impact. We start with a survey of life-cycle engineering research focusing on methodologies and tools. Further, the paper addresses critical research issues in life-cycle design tools: design representation and measures for life-cycle evaluation. The paper describes our design representation scheme based on a semantic network that is effective for evaluating the structural layout. Evaluation measures for serviceability and recyclability illustrate the practical use of these representation schemes.

A Smooth Contact Algorithm Using Cubic Spline Surface Interpolation for Rigid and Flexible Bodies

2013 ◽  
Author(s):  
Juhwan Choi ◽  
Jin Hwan Choi
Keyword(s):  
Contact Force ◽  
Cubic Spline ◽  
Surface Representation ◽  
Flexible Bodies ◽  
Contact Algorithm ◽  
Surface Interpolation ◽  
Spline Surface ◽  
Smooth Contact ◽  
Representation Method ◽  
Detailed Search

The contact analysis of multi-flexible-body dynamics (MFBD) has been an important issue in the area of computational dynamics because the realistic dynamic analysis of many mechanical systems includes the contacts among rigid and flexible bodies. But, until now, the contact analysis in the multi-flexible-body dynamics has still remained as a big, challenging area. Especially, the most of contact algorithms have been developed based on the facetted triangles. As a result, the contact force based on the facetted surface was not accurate and smooth because the geometrical error is already included in the contact surface representation stage. This kind of error can be very important in the precise mechanism such as gear contact or cam-valve contact problems. In order to resolve this problem, this study suggests a cubic spline surface representation method and related contact algorithms. The proposed contact algorithms are using the compliant contact force model based on the Hertzian contact theory. In order to evaluate the smooth contact force, the penetration depth and contact normal directions are evaluated by using the cubic spline surface interpolation. Also, for the robust and efficient contact algorithm development, the contact algorithms are divided into four main parts which are a surface representation, a pre-search, a detailed search and a contact force generation. In the surface representation part, we propose a smooth surface representation method which can be used for smooth rigid and flexible bodies. In the pre-search, the algorithm performs collision detection and composes the expected contact pairs for the detailed search. In the detailed search, the penetration depth and contact reference frame are calculated with the cubic spline surface interpolation in order to generate the accurate and smooth contact force. Finally in the contact force generation part, we evaluate the contact force and Jacobian matrix for the implicit time integrator.

Sign in / Sign up

Export Citation Format

Share Document