scholarly journals Iso-material contour representation for process planning of heterogeneous object model

2020 ◽  
Vol 7 (4) ◽  
pp. 498-513
Author(s):  
G K Sharma ◽  
B Gurumoorthy
Keyword(s):  
Additive Manufacturing ◽  
Material Composition ◽  
Composition Material ◽  
Object Model ◽  
Material Distribution ◽  
Process Plan ◽  
Contour Representation ◽  
Heterogeneous Objects ◽  
Raster Scan ◽  
Heterogeneous Object

Abstract Additive manufacturing is emerging as the preferred process for making heterogeneous objects. Planning the deposition of material is more complex for heterogeneous objects as the material variation has to be tracked along the path. This paper proposes an iso-material contour representation to generate the process plan for additive manufacturing given a smooth representation of heterogeneous object model. These contours represent the iso-material paths for deposition. As these paths shift along the direction of the gradation of material distribution, the deposition respects the gradient of the designed material distribution unlike iso-oriented paths generated by a raster scan method. Since the paths have the same material composition, material frequent change in the material composition is avoided, which, in turn, avoids the uneven deposition caused by the frequent start and stop of deposition while the material is being changed along the paths generated by the traditional raster scan. Associativity between the contours and the corresponding designed material feature is maintained, and therefore, changes in material composition are automatically propagated to the process plan.

Build Direction for Improved Process Plan in Multi-Material Additive Manufacturing

2014 ◽  
Author(s):  
Bashir Khoda
Keyword(s):  
Additive Manufacturing ◽  
Material Object ◽  
Layer By Layer ◽  
Multiple Features ◽  
Process Plan ◽  
Material Deposition ◽  
Heterogeneous Object ◽  
Build Time ◽  
Material Process ◽  
Manufacturing Techniques

Current additive manufacturing processes mostly accustomed with mono-material process plan algorithm to build object layer by layer. However, building a multi-material or heterogeneous object with an additive manufacturing system is fairly new but emerging concept. Unlike mono-material object, heterogeneous object contains multiple features or inhomogeneous architecture and can be decomposed into two dimensional heterogeneous layers with islands where each island represents associated feature’s properties. The material deposition path-plan in such multi-feature/multi-contour layers requires more resources and may affect the part integrity, quality, and build time. A novel framework is presented in this paper to determine the optimum build direction for heterogeneous object by differentiating the slice based on the resources requirement. Slices are bundled based on the heterogeneity and the effect of build directions are quantified considering the feature characteristics and manufacturing attributes. The proposed methodology is illustrated by examples with 50% or more homogeneous slices along the optimum build direction. The outcome would certainly benefit the process plan for multi-material additive manufacturing techniques.

scholarly journals Modelling multiply connected heterogeneous objects using mixed-dimensional material reference features

2018 ◽  
Vol 6 (3) ◽  
pp. 337-347 ◽  
Author(s):  
G.K. Sharma ◽  
B. Gurumoorthy
Keyword(s):  
Ab Initio ◽  
High Performance ◽  
Complex Geometry ◽  
Medial Axis ◽  
High Hardness ◽  
Material Composition ◽  
Material Distribution ◽  
Heterogeneous Objects ◽  
Form Features ◽  
General Method

Abstract This paper proposes a general method for ab-initio modelling and representation of heterogeneous objects that are associated with complex material variation over complex geometry. Heterogeneous objects like composites and naturally occurring objects (bones, rocks and meteorites) possess multiple and often conflicting properties (like high hardness and toughness simultaneously), which are associated with random and irregular material distribution. Modelling such objects is desired for numerical analysis and additive manufacturing to develop bio-implants, high-performance tools etc. However, it is difficult to define and map the arbitrary material distribution within the object as the material distribution can be independent of the shape parameters or form features used to construct its solid model. This paper represents the source of random and irregular material distribution by mixed-dimensional entities with a focus on modelling compositional heterogeneity. The domain of effect of each material reference entity is defined automatically by using Medial Axis Transform (MAT), where the material distribution can be intuitively prescribed, starting from the material reference entity and terminating at the medial axis segment bounding the corresponding domain. Within such a domain, the spatial variation of the material is captured by a distance field from the material reference entity, which can be controlled locally and independently. These domains are stored using the neighbourhood relation for efficient operations like altering material distribution across the material reference entity and material evaluation for a given geometric location. Results from an implementation for 2.5D objects are shown and the extension to 3D objects is discussed. Highlights Hybrid representation for complex heterogeneous objects. General method for ab-initio modelling of complex heterogeneous objects capture arbitrary material distribution by automatic domain decomposition. Local control of material composition through MAT around material feature. Specification of material composition without adding new entities to shape model.

Optimal three-dimensional design of functionally graded parts for additive manufacturing using Tamura–Tomota–Ozawa model

2021 ◽  
pp. 146442072110116
Author(s):  
Priyambada Nayak ◽  
Amir Armani
Keyword(s):  
Additive Manufacturing ◽  
Functionally Graded Materials ◽  
Three Dimensional ◽  
Functionally Graded ◽  
Material Composition ◽  
Von Mises Stress ◽  
Material Distribution ◽  
Graded Materials ◽  
Finite Element Software ◽  
Graded Structures

Although some conventional manufacturing technologies are capable of producing functionally graded materials, only a few additive manufacturing processes are able to build functionally graded materials with complex distribution of material composition. To exploit this unique advantage, we have developed a new methodology capable of optimization of material distribution for three-dimensional parts for any given conditions. Representation of material distribution was done through a new technique by extending the nonuniform rational basis spline surfaces to four-dimensional space. Mori–Tanaka, Levin, and Tamura–Tomota–Ozawa models were employed for the estimation of effective material properties of functionally graded structures. Subroutines were developed in a commercial finite element software to enable the analysis of parts made from functionally graded material. A constrained particle swarm optimization method was selected and implemented to optimize the material composition distribution taking into account the additive manufacturing limitations. As a case study, the material distribution optimization of a functionally graded femur bone plate under thermomechanical loading was considered. The objective was to maximize the safety factor; i.e. the ratio of local yield strength of the functionally graded plate over the von Mises stress. The results showed significant improvement compared to nonoptimal part and demonstrated the efficacy of the proposed methodology.

Heterogeneous Object Modeling Approach Based on ACIS and HOOPS

2009 ◽  
Vol 419-420 ◽  
pp. 793-796
Author(s):  
An Ping Xu ◽  
Ting Zang ◽  
Zhen Peng Ji ◽  
Yun Xia Qu
Keyword(s):  
Inverse Distance Weighting ◽  
Material Composition ◽  
Functional Modules ◽  
Object Modeling ◽  
Modeling Approach ◽  
Heterogeneous Objects ◽  
Distance Weighting ◽  
Heterogeneous Object ◽  
Heterogeneous Object Modeling ◽  
Inverse Distance

This paper deals with the background and significance of working on heterogeneous objects modeling and briefly introduces the architecture of ACIS and HOOPS and their corresponding functional modules. Based on inverse-distance weighting algorithm to determine the material composition within the object, the general approach to modeling the heterogeneous objects by using ACIS and HOOPS is introduced and demonstrated via some simple examples.

FEA-Based Design of Heterogeneous Objects

2006 ◽  
Author(s):  
Ki-Hoon Shin
Keyword(s):  
Finite Element ◽  
Functionally Graded ◽  
Design Stage ◽  
Solid Model ◽  
Finite Element Models ◽  
Object Model ◽  
Material Distribution ◽  
Heterogeneous Objects ◽  
Design Cycle ◽  
Heterogeneous Solid

Finite Element Analysis (FEA) is an important step for the design of structures or components formed by heterogeneous objects such as multi-materials, Functionally Graded Materials (FGMs), etc. The main objective of the FEA-based design of heterogeneous objects is to simultaneously optimize both geometry and material distribution over the design domain (e.g., Homogenization Design Method). However, the accuracy of the FEA-based design wholly depends on the quality of the finite element models. Therefore, there exists an increasing need for generating finite element models adaptive to both geometric complexity and material distribution. This paper introduces a method for FEA-based design of heterogeneous objects. At the design stage, a heterogeneous solid model is first created by referring to the libraries of primary materials and composition functions that are already available in the field of material science. The heterogeneous solid model is then discretized into an object model onto which appropriate material properties are mapped. Discretization converts continuous material variations inside an object into stepwise variations. Next, the object model is adaptively meshed and converted into a finite element model. The meshing algorithm first creates nodes on the iso-material curves (or surfaces) of heterogeneous solid models. Triangular (or tetrahedral) meshes are then generated inside each iso-material region formed by iso-material curves (or surfaces). FEA using commercial software is finally performed to estimate stress levels. This FEA-based design cycle is repeated until a satisfactory solution is obtained. If the design objective is satisfactory, the object model is fed to the fabrication system where a process planning is performed to create instructions for LM machines. An example (FGM pressure vessel) is shown to illustrate the entire FEA-based design cycle.

Automatic Toolpath Generation for Heterogeneous Objects Manufactured by Directed Energy Deposition Additive Manufacturing Process

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Xinyi Xiao ◽  
Sanjay Joshi
Keyword(s):  
Additive Manufacturing ◽  
Energy Deposition ◽  
Single Layer ◽  
Functionally Graded ◽  
Material Composition ◽  
Graded Materials ◽  
Directed Energy Deposition ◽  
Toolpath Generation ◽  
Heterogeneous Objects ◽  
Directed Energy

A heterogeneous object (HO) refers to a solid component consisting of two or more material primitives distributed either continuously or discontinuously within the object. HOs are commonly divided into three categories. The first category has distinct material domains separating the different materials. The second, called functionally graded materials (FGMs), has continuous variation of material composition that produces gradient in material properties. The third category allows for any combinations of the first two categories within the same part. Modeling and manufacturing of HOs has recently generated more interest due to the advent of additive manufacturing (AM) technology that makes it possible to build such parts. Directed energy deposition (DED) processes have the potential for depositing multiple powdered materials in various compositions in the process of creating a single layer of material. To make this possible, tool paths that provide proper positioning of the deposition head and proper control over the material composition are required. This paper presents an approach for automatically generating the toolpath for any type of HO considering the material composition changes that are required on each layer. The toolpath generation takes into account the physical limitations of the machine associated with powder delivery and ability to continually grade the materials. Simulation results using the toolpath generation methodology are demonstrated by several example parts.

scholarly journals VOLCO-X: numerical simulation of material distribution and voids in extrusion additive manufacturing

2021 ◽  
pp. 101900
Author(s):  
Rafael Quelho de Macedo ◽  
Rafael Thiago Luiz Ferreira ◽  
Andrew Gleadall ◽  
Ian Ashcroft
Keyword(s):  
Numerical Simulation ◽  
Additive Manufacturing ◽  
Material Distribution

scholarly journals A Shape Optimization Method for Part Design Derived from the Buildability Restrictions of the Directed Energy Deposition Additive Manufacturing Process

Designs ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 19
Author(s):  
Andreas K. Lianos ◽  
Harry Bikas ◽  
Panagiotis Stavropoulos
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Energy Deposition ◽  
Design Method ◽  
Current Trend ◽  
Internal Stresses ◽  
Material Distribution ◽  
Load Case ◽  
Design Elements ◽  
Industrial Sectors

The design methodologies and part shape algorithms for additive manufacturing (AM) are rapidly growing fields, proven to be of critical importance for the uptake of additive manufacturing of parts with enhanced performance in all major industrial sectors. The current trend for part design is a computationally driven approach where the parts are algorithmically morphed to meet the functional requirements with optimized performance in terms of material distribution. However, the manufacturability restrictions of AM processes are not considered at the primary design phases but at a later post-morphed stage of the part’s design. This paper proposes an AM design method to ensure: (1) optimized material distribution based on the load case and (2) the part’s manufacturability. The buildability restrictions from the direct energy deposition (DED) AM technology were used as input to the AM shaping algorithm to grant high AM manufacturability. The first step of this work was to define the term of AM manufacturability, its effect on AM production, and to propose a framework to estimate the quantified value of AM manufacturability for the given part design. Moreover, an AM design method is proposed, based on the developed internal stresses of the build volume for the load case. Stress tensors are used for the determination of the build orientation and as input for the part morphing. A top-down mesoscale geometric optimization is used to realize the AM part design. The DED Design for Additive Manufacturing (DfAM) rules are used to delimitate the morphing of the part, representing at the same time the freeform mindset of the AM technology. The morphed shape of the part is optimized in terms of topology and AM manufacturability. The topology optimization and AM manufacturability indicator (TMI) is introduced to screen the percentage of design elements that serve topology optimization and the ones that serve AM manufacturability. In the end, a case study for proof of concept is realized.

Approximate Functionally Graded Materials for Multi-Material Additive Manufacturing

2018 ◽  
Author(s):  
Yuen-Shan Leung ◽  
Huachao Mao ◽  
Yong Chen
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Functionally Graded Materials ◽  
Functionally Graded ◽  
Gradual Transition ◽  
Material Distribution ◽  
Graded Materials ◽  
Base Materials ◽  
Multiple Materials ◽  
Am Processes

Functionally graded materials (FGM) possess superior properties of multiple materials due to the continuous transitions of these materials. Recent progresses in multi-material additive manufacturing (AM) processes enable the creation of arbitrary material composition, which significantly enlarges the manufacturing capability of FGMs. At the same time, the fabrication capability also introduces new challenges for the design of FGMs. A critical issue is to create the continuous material distribution under the fabrication constraints of multi-material AM processes. Using voxels to approximate gradient material distribution could be one plausible way for additive manufacturing. However, current FGM design methods are non-additive-manufacturing-oriented and unpredictable. For instance, some designs require a vast number of materials to achieve continuous transitions; however, the material choices that are available in a multi-material AM machine are rather limited. Other designs control the volume fraction of two materials to achieve gradual transition; however, such transition cannot be functionally guaranteed. To address these issues, we present a design and fabrication framework for FGMs that can efficiently and effectively generate printable and predictable FGM structures. We adopt a data-driven approach to approximate the behavior of FGM using two base materials. A digital material library is constructed with different combinations of the base materials, and their mechanical properties are extracted by Finite Element Analysis (FEA). The mechanical properties are then used for the conversion process between the FGM and the dual material structure such that similar behavior is guaranteed. An error diffusion algorithm is further developed to minimize the approximation error. Simulation results on four test cases show that our approach is robust and accurate, and the framework can successfully design and fabricate such FGM structures.

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