Browsing by Subject "topology optimization"

Now showing 1 - 6 of 6
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    Design Optimization of Plastic Injection Tooling for Additive Manufacturing
    (Elsevier, 2017) Wu, Tong; Jahan, Suchana A.; Zhang, Yi; Zhang, Jing; El-Mounayri, Hazim; Tovar, Andres; Mechanical Engineering, School of Engineering and Technology
    This work presents a systematic and practical finite element based design optimization approach for the injection tooling adaptive to additive manufacturing (AM) technology using stereo-lithography (SLA) and powder bed fusion (PBF). First a thermomechanical optimization of conformal cooling is implemented to obtain the optimal parameters associated with conformal cooling design. Then, a multiscale thermomechanical topology optimization is implemented to obtain a lightweight lattice injection tooling without compromising the thermal and mechanical performance. The design approach is implemented to optimize a real design mold and the final optimal design is prototyped in SLA and the manufacturability in PBF has been discussed.
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    Development of a Cone CVT by SDPD and Topology Optimization
    (SAE, 2019-04) Patil, Nikhil; Malekipour, Ehsan; El-Mounayri, Hazim; Mechanical and Energy Engineering, School of Engineering and Technology
    The automotive industries have undergone a massive change in the last few decades. Nowadays, automotive industries and OEM manufacturers implement various innovative ideas to ensure the desired comfort while minimizing the cost, weight, and manufacturing time. Transmission system plays a major role in the aforementioned items. This paper aims to develop a conical roller with belt Continuously Variable Transmission (CVT) System by employing the System Driven Product Development (SDPD) approach and topology optimization of its traditional design. Furthermore, this paper explains the design steps of the CVT and its advantages and limitations compared with the other automatic transmission systems.
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    An efficient 3D topology optimization code written in Matlab
    (Springer, 2015-06) Liu, Kai; Tovar, Andres; Department of Mechanical Engineering, School of Engineering
    This paper presents an efficient and compact Matlab code to solve three-dimensional topology optimization problems. The 169 lines comprising this code include finite element analysis, sensitivity analysis, density filter, optimality criterion optimizer, and display of results. The basic code solves minimum compliance problems. A systematic approach is presented to easily modify the definition of supports and external loads. The paper also includes instructions to define multiple load cases, active and passive elements, continuation strategy, synthesis of compliant mechanisms, and heat conduction problems, as well as the theoretical and numerical elements to implement general non-linear programming strategies such as SQP and MMA. The code is intended for students and newcomers in the topology optimization. The complete code is provided in Appendix C and it can be downloaded from http://​top3dapp.​com.
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    Heat Conduction and Geometry Topology Optimization of Support Structure in Laser-based Additive Manufacturing
    (Springer, 2018) Malekipour, Ehsan; Tovar, Andres; El-Mounayri, Hazim; Mechanical Engineering, School of Engineering and Technology
    Laser-based metal additive manufacturing technologies such as Selective Laser Sintering (SLS) and Selective Laser Melting (SLM) allow the fabrication of complex parts by selectively sintering or melting metallic powders layer by layer. Although elaborate features can be produced by these technologies, heat accumulation in overhangs leads to heat stress and warping, affecting the dimensional and geometrical accuracy of the part. This work introduces an approach to mitigate heat stress by minimizing the temperature gradient between the heat-accumulated zone in overhangs and the layers beneath. This is achieved by generating complex support structures that maintain the mechanical stability of the overhang and increase the heat conduction between these areas. The architecture of the complex support structures is obtained by maximizing heat conduction as an objective function to optimize the topology of support structure. This work examines the effect of various geometries on the objective function in order to select a suitable one to consume less material with almost same conduction. Ongoing work is the development of an experimental testbed for verification.
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    Thermo-fluid Topology Optimization and Experimental Study of Conformal Cooling Channels for 3D Printed Plastic Injection Molds
    (Elsevier, 2019) Jahan, Suchana; Wu, Tong; Shin, Yung; Tovar, Andres; El-Mounayri, Hazim; Mechanical and Energy Engineering, School of Engineering and Technology
    With the advent of additive manufacturing, innovative design methods, such as network-based techniques, and structural topology optimization have been used to generate complex and highly efficient cooling systems in recent years. However, methods that incorporate coupled thermal and fluid analysis remain scarce. In this paper, a coupled thermal-fluid topology optimization algorithm is introduced for the design of conformal cooling channels. The problem is formulated based on a coupling of Navier- Stokes equations and convection-diffusion equation. The problem is solved by gradient-based optimization after analytical sensitivity derived using adjoint method. With this method, the channel position problem is replaced to a material distribution problem. The material distribution directly depends on the effect of flow resistance, heat conduction, natural and forced convection. The algorithm leads to a two-dimensional conceptual design having optimal heat transfer and balanced flow, which is further transformed into three-dimensional cooling channel design. Here, a comprehensive study is presented, starting from design, simulation, 3D printing process and experimental testing of an injection mold with conformal cooling channels in industrial production environment. A traditional mold model is provided by an industrial collaborator. To enhance the overall thermo-fluid performance of the mold and improve final product quality, a redesign of this mold core is done with conformal cooling channels inside. The final design is 3D printed in pre-alloyed tool-steel powder Maraging Steel using Truprint 3000 metal 3D printing machine. The printed core required some heat treatment and finishing processes and added features to be incorporated to make it production ready. Once all the preparation was complete, the core was tested experimentally in a multicavity injection molding machine in real industrial environment at our industrial partner’s production facility. This paper describes all the steps starting from design, analysis, die 3D printing and finally ending at final experimental testing, as well as recommendations for tool designer and injection molding industry to implement additive manufacturing for their benefit. This paper is not just focused on a specific aspect such as design, simulation or manufacturing, but rather a comprehensive paper presenting a case study on implementation of topology optimization and additive manufacturing in real life industrial production scenario.
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    Topology optimization and 3D printing of a lightweight protective robotic vehicle structure
    (Office of the Vice Chancellor for Research, 2014-04-11) Charlton, Kerri A; Kello, Clayton
    The goal of this project is to design and 3D print a lightweight protective structure of a robotic vehicle structure. Lightweight structure design is a prevalent technology considered by aerospace and automotive engineers that carries challenges associated with protection capabilities under impact. The design problem to be addressed is the optimal structural layout that preserves the mechanical integrity of the structure subjected to external loading using the minimum amount of material. Our work addresses this problem using three-dimensional structural topology optimization. The use of topology optimization allows the designer to synthesize a concept structure by distributing a given amount of material within a volume, referred to as the design domain. The design domain does not include any predetermined structural feature, allowing topology optimization synthesizing innovative, non-conversional designs. In our work, the concept structural design is refined using computer-aided design tools and 3D printed. The final 3D printed component is tested and assembled to the robotic device. This technology involving three-dimensional topology optimization and 3D printing can be applied to the design of innovative structures in micromechanical applications and extended to the aerospace and automotive industries.