4021 Developing Topology Optimization Tools that Enable Efficient Design of AM Cellular Structures

Problem

Additive manufacturing (AM) enables the manufacture of parts previously impossible to machine. Complex geometries can be produced as easily as simple shapes. To fully exploit the AM advantage, design tools need to be established to enable component geometry to be optimized for strength and weight by incorporating features such as lattice and porous structures. Current modeling and simulation (M&S) tools lack efficiency in designing these complex geometries for AM. Incorporating M&S in the development of the CAD or STL file will enable an efficient design and optimization of cellular structured AM products.Additive manufacturing (AM) enables the manufacture of parts previously impossible to machine. Complex geometries can be produced as easily as simple shapes. To fully exploit the AM advantage, design tools need to be established to enable component geometry to be optimized for strength and weight by incorporating features such as lattice and porous structures. Current modeling and simulation (M&S) tools lack efficiency in designing these complex geometries for AM. Incorporating M&S in the development of the CAD or STL file will enable an efficient design and optimization of cellular structured AM products.

Objective

The goal of this project was to develop robust software for design and optimization of AM structural designs based on cellular structures. The outcome of this project not only enabled efficient design and optimization of cellular structured AM products but also integrated cost modeling and design requirements for several AM processes.

This project included the following specific objectives:

1. Develop experimentally-validated micromechanics models for different cellular structures, which were fully implemented into commercial ANSYS finite element analysis (FEA) software.
2. Develop topology optimization and reconstruction algorithms, which were also fully integrated with ANSYS.
3. Demonstrate and validate capability of design and optimization tools on design of a realistic structural component.

Technical Approach

The key innovation in this technology involved the utilization of micromechanics models to capture the effective behavior of cellular structures in FEA. This enabled solving topology optimization problems via FEA more efficiently.

The homogenization-based topology optimization method to optimize variable-density cellular structures efficiently included the following three steps:

1. First, homogenization was performed to capture the effective mechanical properties of cellular structures through the scaling law as a function of relative density.
2. Second, the scaling law was employed directly in the topology optimization algorithm to compute the optimal density distribution for the part being optimized.
3. Third, Boolean operations were employed to reconstruct the CAD model of the optimal variable-density cellular structure.

The project team developed a topology optimization software to design realistic AM cellular structured components. The software has the ability to take a primitive component design and produce the optimal design in a CAD or a STL file that is ready to be additive manufactured with a number of different process-material combinations.

A beta version of the software was successfully deployed to United Technologies Research Center, ExOne, and Materials Sciences Corporation.

At the close of the project, ANSYS was in the process of implementing the developed technology into their world-leading CAE/CAD software, which is expected to be available in the next release of their software.

Enabling design optimization of AM cellular structures achieved a number of sustainability goals, including direct reduction in material use and process energy in manufacturing cellular structures by 50% as compared to bulk solids, and enhanced mechanical properties (e.g. stiffness increases by >100%; strength increases by >200%.)

Accomplishments

The project team developed a topology optimization software to design realistic AM cellular structured components. The software has the ability to take a primitive component design and produce the optimal design in a CAD or a STL file that is ready to be additive manufactured with a number of different process-material combinations. A beta version of the software was successfully deployed to United Technologies Research Center, ExOne, and Materials Sciences Corporation. At the close of the project, ANSYS was in the process of implementing the developed technology into their world-leading CAE/CAD software, which is expected to be available in the next release of their software. Enabling design optimization of AM cellular structures achieved a number of sustainability goals, including direct reduction in material use and process energy in manufacturing cellular structures by 50% as compared to bulk solids, and enhanced mechanical properties (e.g. stiffness increases by >100%; strength increases by >200% .)

Project Participants

Project Principal

Other Project Participants

• ANSYS, Inc.
• United Technologies Research Center
• The ExOne Company
• GE
• ALCOA Inc.ALCOA Inc.
• Materials Science Corporation
• AMRDEC
• ACUTEC Precision Machining Inc.

Public Participants

• U.S. Department of Defense
• National Science Foundation
• U.S. Department of Energy