Ribbed Support Structure for Additive Manufacturing Nested Ducts
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Solution Overview
Problem
Additive manufacturing of complex gas turbine components, such as fuel injectors, often results in nested and elongated parts that are challenging to support during production and require removal of support structures to avoid harmful impacts during operation, especially due to differential thermal expansion.
Innovation Solution
Designing the support structure as an array of ribs that can elastically flex during thermal expansion, eliminating the need for pre-removal and reducing internal stresses and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If support structures are provided to maintain strict dimension and shape tolerances of nested and elongated parts during additive manufacturing, then manufacturing precision is improved, but the support structures have a harmful impact during functioning of the final product
Solution Approach 1:
The support structure's mechanical properties are changed by designing it with rib geometry that provides different stiffness characteristics in different directions. The ribs are configured to be flexible in the radial direction to accommodate thermal expansion, while maintaining stiffness in the axial direction to support overhanging portions during manufacturing.
Solution Approach 2:
The support structure combines features of both rigid and flexible elements through its rib geometry. The ribs act as composite structural elements that provide both support function during manufacturing and thermal accommodation function during operation, eliminating the need for separate support and flexible components.
2Manufacturing precision
If support structures are designed to be rigid to maintain shape tolerances, then manufacturing precision is improved, but internal stresses increase during differential thermal expansion
Solution Approach 1:
The rib geometry parameters are optimized to provide appropriate flexibility. The rib thickness, height, and spacing are designed to create a structure that is sufficiently rigid to support overhanging portions during manufacturing but flexible enough to accommodate radial thermal expansion during operation, thereby reducing internal stresses.
Solution Approach 2:
The support structure transitions from a static rigid structure to a dynamic structure that can adapt its stiffness characteristics. The ribs are designed to flex radially in response to thermal expansion, allowing the structure to dynamically adjust to changing thermal conditions during operation.
3Device complexity
If complex nested and elongated parts are manufactured by additive manufacturing, then device complexity is reduced, but support structures require removal to avoid harmful impacts
Solution Approach 1:
The ribbed support structure is designed to perform multiple functions: providing support during additive manufacturing, accommodating thermal expansion during operation, and eliminating the need for post-manufacturing removal. This multi-functionality simplifies the overall manufacturing process by integrating support structure design into the final product geometry.
Solution Approach 2:
The support structure is designed as a temporary element during manufacturing that naturally serves its purpose and then becomes part of the final functional structure, eliminating the need for expensive and time-consuming removal operations. The ribs are intentionally designed to remain in the final product as functional elements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The ribbed support structure ensures negligible impact during operation and maintains strict shape tolerances, allowing for the conversion of potentially harmful bulk support structures into structural features with limited impact, facilitating additive manufacturing and reducing assembly complexities.
Implementation Method 1
the support structure of a nested portion in an additive manufactured article as an array of ribs. Such ribs, in case of differential thermal expansion at the ends of the ribs during use of the article, will elastically flex in order to follow the differential expansion
Implementation Method 2
differential thermal expansion at the ends of the ribs during use of the article
Data Source
AI summary
An additive manufactured article for a gas turbine having a body with two lateral surfaces elongated in a first direction; at least a nested duct housed within the lateral surfaces and elongated in the first direction; a structure so that the nested duct is structurally connected to an attachment within the lateral surfaces, wherein at least the body, the duct and the structure are manufactured by an additive manufacturing process and the structure includes an array of ribs attached to the duct in order to compensate differential elongation along the first direction of the duct with respect to the attachment of the ribs by flexural deformation.