Hybrid Metal/Composite Lattice Structures: Design for Additive Manufacturing (original) (raw)
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OPTIMIZED DESIGN OF STRUCTURAL COMPONENTS REALIZED THROUGH ADDITIVE MANUFACTURING
Nowadays Additive Manufacturing (AM) is going through a very fast development, spreading in many different mechanical contexts. The main advantages of this technology are: production costs reduction (prototype realization time reduction, raw material consumption reduction, almost zero manpower needed…), significant reliability (compared to the standard production process) and last but not least extreme freedom in product shape design. The last characteristic makes it possible to adopt new design approach focusing on component shape and material distribution optimization; a new design paradigm must be developed to fully take advantage of these opportunities: the designer can develop new concepts with very complex shapes and sophisticated topological solution owing to opportunities yielded by AM with in mind only the week limitations given by this technology. In detail this work aims to highlight a new design strategy that consist of a combination of structural optimization tools (Topology Optimization TO) and non-contact stress field measurement technique (based on thermo-elasticity). The goal is to develop an iterative design procedures which links the design shape optimization with the experimental stress evaluation, allowing a wise material distribution in order to enhance the resistance. The idea is to accomplish an initial designing phase, letting the designer free to define a first rough design concept taking into account the information provided by the TO to exploit the material in the best way. Then, the concept must be verified in both: model numerical F.E.M. analysis and prototype experimental evaluation of the stress field. Eventually, according to the verification analysis results, the model will be modified to reach the desired requirements in terms of allowed deformation, stress resistance and fatigue life. The paper will display the optimization technique iterative process (based on Solid Isotropic Material with Penalization – SIMP – scheme) in a general way and through a practical example. As a reference, this methodology has been applied to a specific test case in order to design and optimize a new concept of a structural mechanical component of a mountain bike. The component was, first realized as a prototype in thermoplastic material and finally designed to be realized in metal for in field application.
Constrained Topology Optimization For Additive Manufacturing Of Structural Components In Ansys®
Progress in Canadian Mechanical Engineering, 2018
Topology Optimization is currently the main technique to optimize an objects structural design. This method commonly produces parts that have exceedingly complex geometry. Additive manufacturing (AM) is the main manufacturing process to produce these optimized designs due to the flexibility and speed it offers. However, results of topology optimization without considering manufacturing process limits, even AM ones, may result in designs that are expensive and difficult to build. This paper presents a topology optimization filter that minimizes the effect of overhang structures. These structures are very difficult to manufacture using conventional AM techniques. In order to constrain the gradient compliances with respect to densities and converge the results towards a structure with the least amount of overhang structures, sensitivities are modified using the proposed filter. To implement the proposed filter and the base topology optimization methods ESO and SIMP, ANSYS Parametric Design Language (APDL) is employed within the ANSYS ® Workbench™ environment. The results of a case study using the different topology optimization methods are investigated. Finally, an implementation of the proposed AM filter is used to solve an MBB-beam problem. The result is a structure that needs the least amount of support structure.
10th AIAA Multidisciplinary Design Optimization Conference, 2014
Additive manufacturing, more commonly known as 3D printing is a rapidly developing, thoroughly novel means of producing complex, previously difficult to manufacture components. Slowly divorcing itself from previously held preconceptions of rapid prototyping and now capable of producing comparable structures from materials such as titanium and high strength nickel alloys, it is a means of manufacturing structures deemed too complex for existing fabrication techniques. Whilst free of conventional constraints, the unique intricacies of the manufacturing process can lead to the creation of factors, detrimental to production success. The research detailed within this paper demonstrates through example, how the orientation of a part prior to build can be optimized in order to significantly mitigate these effects and to maximize build economics. Furthermore the research details a new method for the combined assessment and tailored structural topology optimization of parts intended for production by specific additive manufacturing technologies.
Application of layout optimization to the design of additively manufactured metallic components
Structural and Multidisciplinary Optimization, 2016
Additive manufacturing ('3D printing') techniques provide engineers with unprecedented design freedoms, opening up the possibility for stronger and lighter component designs. In this paper 'layout optimization' is used to provide a reference volume and to identify potential design topologies for a given component, providing a useful alternative to continuum based topology optimization approaches (which normally require labour intensive post-processing in order to realise a practical component). Here simple rules are used to automatically transform a line structure layout into a 3D continuum. Two examples are considered: (i) a simple beam component subject to three-point bending; (ii) a more complex air-brake hinge component, designed for the Bloodhound supersonic car. These components were successfully additively manufactured using titanium Ti-6Al-4V, using the Electron Beam Melting (EBM) process. Also, to verify the efficacy of the process and the mechanical performance of the fabricated
Lessons Learnt from a National Competition on Structural Optimization and Additive Manufacturing
Current Chinese Science, 2020
Background:: As an advanced design technique, topology optimization has received much attention over the past three decades. Topology optimization aims at finding an optimal material distribution in order to maximize the structural performance while satisfying certain constraints. It is a useful tool for the conceptional design. At the same time, additive manufacturing technologies have provided unprecedented opportunities to fabricate intricate shapes generated by topology optimization. Objective:: To design a highly efficient structure using topology optimization and to fabricate it using additive manufacturing. Method:: The bi-directional evolutionary structural optimization (BESO) technique provides the conceptional design, and the topology-optimized result is post-processed to obtain smooth structural boundaries. Results:: We have achieved a highly efficient and elegant structural design which won the first prize in a national competition in China on design optimization and add...
Method for integration of lattice structures in design for additive manufacturing
2017
It is now possible to manufacture metallic lattice structures easily with additive manufacturing. Lattice structures can be used to produce high strength low mass parts. However, it does not exist a method to design lattice structures for additive manufacturing. This PhD focuses on lattice structure design methods and manipulation in CAD, CAE and CAM tools to facilitate the wide use of lattice structures in products. The thesis addressed the following research questions:• Why are lattice structures so little used in part designs?• What are the information necessary to help designers to design parts containing lattice structures?• How can lattice structures be created quickly and easily in CAD?The main contributions are:• An evaluation of current CAD tools in terms of human machine interface, CAD file formats, CAE and CAM to design lattice structures was conducted. The results show that current CAD tools and CAD file formats have insufficient performance in the context of design for ...
Engineering with Computers
Today, being able to generate and produce shapes that fit mechanical and functional requirements and having as low as possible mass is crucial for aerospace and automotive applications. Besides, the rise of new additive manufacturing technologies has widened the possibilities for designing and producing complex shapes and internal structures. However, current models, methods and tools still represent a limitation to that new horizon of printable shapes. This paper addresses the way internal lattice structures can be generated and optimized to reduce the mass of a product. A new framework is introduced that allows the modeling and optimization of non-uniform patterned lattice structures. Using non-uniform structures, additional degrees of freedom are introduced and allow the definition of a wide variety of shapes which can better fit the requirements. First, a non-uniform patterned lattice structure is generated using the results of an initial finite element analysis. This initial structure is then optimized while iteratively removing the beams considered as useless with respect to a user-specified mechanical criteria. At each iteration, the lattice structure is sent to a finite element solver that returns the von Mises stress map used to drive the simplification process. Here, the simulations are performed on the wireframe lattice structures to speed up the optimization loops. Once this process is completed, the final structure is no longer fully patterned, but it is reorganized to reduce the mass while satisfying the mechanical criteria. This approach is illustrated with examples coming from our prototype software.
Design for Additively Manufactured Structure: An Assessment
International Journal of Trend in Scientific Research and Development
The design of lightweight structures realized via additive manufacturing has been drawing considerable amount of attentions in academia and industries for a wide range of applications. However, various challenges remain for AM lightweight structures to be reliably used for these applications. For example, despite extensive advancement with geometric design, there still lacks adequate understanding with the process-material property relationship of AM lightweight structures. In addition, a more integrated design approach must also be adopted in order to take non-uniform material design into consideration. In our works, a design approach based on unit cell cellular structure was taken in the attempt to establish a comprehensive design methodology for lightweight structures. Analytical cellular models were established to provide computationally efficient property estimation, and various design factors such as size effect, stress concentration and joint angle effect were also investigated in order to provide additional design guidelines. In addition, it was also found that the geometry and microstructure of the cellular structures are dependent on both the process setup and the feature dimensions, which strongly support the argument to establish a multi-scale hierarchical cellular design tool.
Proceedings of CAD'19
In the last few years, considerable attention has been paid to additive manufacturing (AM) technologies [1] to redesign and modify the industrial products with regard to its merits. At the initial stage of technology development, AM was mostly used as a building platform for prototyping, whereas its usage has been recently extended to industrial applications. Amid the different methods of AM technology, the development of metal AM, in particular, Powder Bed Fusion (PBF) and metal Binder Jetting (MBJ), facilitate the production of high-quality and complex parts in several sectors of industry such as aerospace, medical, architecture and civil engineering. Understanding the novel advantage of metal 3d-printing in the development of high-performance and functional parts for applications in the construction sector enables researchers to propose different design and form-finding methods for construction components.
Recent progress in additive manufacturing (AM) allows for printing customized products with multiple materials and complex geometries that could form the basis of multimaterial designs with high performance and novel functions. Effectively designing such complex products for optimal performance within the confines of AM constraints is challenging due to the need to consider fabrication constraints while searching for optimal designs with a large number of variables, which stem from new AM capabilities. In this study, fabrication constraints are addressed through empirically characterizing multiple printed materials’ Young’s modulus and density using a multimaterial inkjet-based 3D-printer. Data curves are modeled for the empirical data describing two base printing materials and 12 mixtures of them as inputs for a computational optimization process. An optimality criteria (OC) method is developed to search for solutions of multimaterial lattices with fixed topology and truss cross section sizes. Two representative optimization studies are presented and demonstrate higher performance with multimaterial approaches in comparison to using a single material. These include the optimization of a cubic lattice structure that must adhere to a fixed displacement constraint and a compliant beam lattice structure that must meet multiple fixed displacement constraints. Results demonstrate the feasibility of the approach as a general synthesis and optimization method for multimaterial, lightweight lattice structures that are large-scale and manufacturable on a commercial AM printer directly from the design optimization results.