A new software framework for unstructured mesh representation and manipulation

This research presents a unique new software framework for representing and manipulating unstructured meshes in parallel, for use in modern scientific simulation codes. Due to the central nature of the unstructured mesh, this framework provides a variety of functionality, desirable throughout the lifecycle of an application, such as IO, parallel partitioning, phantom node data updates, adaptive refinement, derefinement and load balancing. What makes the framework unique is a focus on generality: like a database, the user provides a programmatic schema defining the structure of the mesh, including topological descriptions of the valid mesh entities. The system extracts adjacency information from this input and allows the use of high-level queries for manipulating and processing the mesh. Advanced C++ techniques allow for a combination of high extensibility and highly optimizable code. New applications can be built quickly, by taking advantage of the framework’s capabilities. Existing codes can incorporate the framework with minimal modification, due to the use of data proxies that mediate between the framework’s internal data structures and existing user data. The design and implementation of this framework are discussed, and several representative applications are presented. Scalability results and analysis are included

Constrained deformation for evolutionary optimization

Sieger D. Constrained deformation for evolutionary optimization. Bielefeld: Universität Bielefeld; 2017.This thesis investigates shape deformation techniques for their use in design optimization tasks. In the first part, we introduce state-of-the-art deformation methods and evaluate them in a set of representative benchmarks. Based on these benchmarking results, we derive essential criteria and features a deformation technique should satisfy in order to be successfully applicable within design optimization. In the second part, we concentrate on the application and improvement of deformation techniques based on radial basis functions. We present and evaluate a unified framework for surface and volume mesh deformation and investigate questions of performance and scalability. In the final third part, we concentrate on the integration of additional constraints into the deformation, thereby improving the overall effectiveness of the design optimization process and fostering the creation of more feasible and producible design variations. We present a novel shape deformation technique that effectively maintains different types of geometric constraints such as planarity, circularity, or characteristic feature lines during deformation. At the same time, our method provides a unique level of modeling flexibility, quality, robustness, and scalability. Finally, we integrate techniques for automatic constraint detection directly into our deformation framework, thereby making our method more easily applicable within complex design optimization scenarios

MSTK - A Flexible Infrastructure Library for Developing Mesh Based Applications

MSTK is a powerful framework for low-level creation and manipulation of unstructured meshes. MSTK is not a mesh generator but it can be used to develop advanced mesh generation software and other mesh-based applications. The salient feature of MSTK is that it is allows multiple mesh representations while presenting a common functional interface to the developer. This allows application developers to use a mesh representation optimized for their particular algorithms. MSTK allows developers to focus on their applications rather than on the details of mesh data structures

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