J19
Optimisation 3

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16:05
conference time (CEST, Berlin)
Design Optimization of Thin Aluminum Windows for Pressurized Systems in Spallation Neutron Source Instruments
28/10/2021 16:05 conference time (CEST, Berlin)
Room: J
S. Kaminskas (Oak Ridge National Laboratory, USA)
S. Kaminskas (Oak Ridge National Laboratory, USA)
The abundance of scientific experiments is available with Instruments of Spallation Neutron Source (SNS) at Oak Ridge National Laboratory in Tennessee. Each Instrument generally represents a set of engineering components, lined-up to pass the neutron beam through them until it finally reaches detector. Many of such components have vacuum inside and input/output aluminum windows which must be thin enough to not obstruct the neutron beam passing through. The thin windows, on the other hand, must reliably hold the atmospheric pressure from outside not compromising the safety of instrument operation. Insufficient strength and durability of the window may cause its rupture with necessary instrument shut down for costly repairs. Two major types of windows were analyzed and optimized: clamped plane aluminum sheet and machined window with fillet. To keep the stresses below safety margin at plane sheet window, the design concepts of “prestressed” and “supported” window were developed. Design of Experiment (DOE) was performed to create the response surfaces for different window design types using Isight and Abaqus software. Parametric optimization was performed next assuming that the higher stress and fatigue allowable margins will contribute to the higher robustness and reliability. To ensure that safety requirements are met, the additional plastic and fatigue analyses were completed with Abaqus and ASME recognized advanced Fe-Safe (structural fatigue) software. Results also were validated by comparing them with results for two other windows from instruments at different neutron beamlines. Performed analyses were also repeated for comprehensiveness by using solid, shell, axisymmetric shell, and membrane types of finite elements. Obtained results enabled to identify the optimal window and clamp assembly design or the possible trade-offs for the most feasible design if needed. The specifics of applied technology together with the most characteristic results will be presented. *The SNS is sponsored by the Office of Science, US Department of Energy, and managed by UT-Battelle, LLC
Design Optimization, Design of Experiment, Neutron Spallation, Pressure Systems
16:25
conference time (CEST, Berlin)
Adjoint-based Topology Optimization - Maximizing Heat Transfer of a Brake Cooling Duct
28/10/2021 16:25 conference time (CEST, Berlin)
Room: J
S. Petropoulou (Siemens Digital Industries Software, GBR); J. Gaenz (Siemens Digital Industries Software, DEU); F. Ross (Siemens Digital Industries Software, USA)
S. Petropoulou (Siemens Digital Industries Software, GBR); J. Gaenz (Siemens Digital Industries Software, DEU); F. Ross (Siemens Digital Industries Software, USA)
Additive manufacturing has made it possible to push the limits of designs beyond the skills and imagination of traditional design engineers. Topology optimization closes the gap between the possibilities and the automation in obtaining those organic optimized shapes. A key class of engineering problems, fluid and thermal applications, are benefiting from the advances on those two design and manufacturing technologies. In this paper, a brake cooling duct is optimized in terms of increasing the heat transfer delivered to the front brake rotor. Topology optimization is automatically designing a new brake duct within the constraint space available behind the front bumper. The heat transfer coefficient on the rotor is used as a cost function to be maximized while we enforce a volume constraint and a minimum pressure drop through the brake duct. At the end of the optimization loop the newly designed duct is exported and reintroduced in the car geometry in order to assess the actual gain. A further adjoint shape optimization step can push the design to even further performance gains. The topology optimization method used here is a feature of Simcenter STAR-CCM+. It is based on a level set approach which results in designs with less kinks and folds. This can reduce the clean-up and CAD reproduction time significantly and ultimately reducing the cost of production. The level set approach further improves the robustness of the optimization solutions allowing users to run with semi-converged adjoint and flow solutions for the intermediate step. The topology optimization method features an integrated constrained optimization method that allows you to solve engineering problems with competing attributes by defining one objective and multiple flow and thermal constraints as well as volume constraint. Topology optimization reducing the design and computational effort needed to determine an optimized shape, while additive manufacturing makes it possible to produce the optimized duct design.
Topology optimization, adjoint, heat transfer, break cooling duct
16:45
conference time (CEST, Berlin)
Improving the Contact Lens Wearer Daily Experience by Simulation and Optimization Across Multiple Aspects of Performance
28/10/2021 16:45 conference time (CEST, Berlin)
Room: J
S. Zeinali, G. Richardson (Johnson & Johnson Vision, USA)
S. Zeinali, G. Richardson (Johnson & Johnson Vision, USA)
The daily experience of a contact lens wearer is affected by many aspects of the design of the lens, from handling of the lens after removal from the package to the ease of insertion on the eye and the comfort throughout the day and finally to the removal in the evening. Different Finite Element Models have been developed that simulate these aspects independently. These simulations have provided great insights into how the mechanical design and shape of the lens relate to these aspects of wearer experience. Several simulation metrics have been identified that correlate with the experience of contact lens wearer, e.g. likelihood of lens folding inside the package (causing difficulty to pick up the lens), likelihood of lens flipping inside-out (inducing discomfort and uncorrected vision) or the deformed shape of the lens on the finger when picked up from the package (causing difficulty in inserting the lens on eye usually resulting in multiple attempts). It is usually the case that improving one aspect of lens wearer experience comes at the cost of compromising other. There is a need for integration of these models, a design optimization algorithm, and a global objective function that addresses all aspects of the wearer experience. This would enable the development of next generation lenses with a potential to significantly improve the wearer experience while reducing the time to market. An automated, integrated model has been created using modeFRONTIER to drive both MSC Marc simulations and analytical MATLAB post processing programs. A virtual DOE on multiple design parameters is conducted to identify the effects and interactions of individual design factors in lens handling performances. Then, with multiple objective functions, optimization has been performed to find the optimal set of design parameters, offering us with the potential to simultaneously improve comfort, handling and insertion aspects of the lens designs.
Optimization, Simulation, Patient Experience, MSC Marc, ESTECO modeFRONTIER, VCollab
17:05
conference time (CEST, Berlin)
Utilizing CFD Fields for Fluid Domain Optimization
28/10/2021 17:05 conference time (CEST, Berlin)
Room: J
M. Vlahinos (nTopology, USA)
M. Vlahinos (nTopology, USA)
Basic structural optimization has been available for the past three decades and with the capabilities of additive manufacturing and implicit geometric generation tools, these generative design techniques have expanded the capabilities of structural optimization. There are a few existing efforts to generate optimized geometries specifically for fluid applications, however, these efforts are quite cumbersome and hard to implement early in the design phase. Typically, the CFD simulations are performed late in the design process for Validation & Verification of the design. To enable truly fluid-optimized components the use of CFD needs to be used earlier in the design process. This paper will present a new method to leverage the use of CFD simulation fields at the onset of the design process to generate an optimum geometry for fluid performance. There are some common constraints a design engineer is faced with. One is generating a geometry that equalizes the flow rate at several outlets with a given inlet flow rate. While another is to determine an optimum topology within a given design domain that minimizes pressure drop. Skilled CFD & design practitioners can come up with these topologies but this process requires several iterations and significant domain knowledge. As product complexity increases and multiple design constraints get introduced this task quickly becomes infeasible with our current methodologies. Today, a simple, reusable design process can utilize the three dimensional fields (velocity, pressure, turbulence, etc) from CFD simulation coupled with a powerful implicit geometric modeler to generate optimal geometries. The imported three dimensional field is truncated based on the magnitude of the nodal results to produce an optimized geometry. A new CFD simulation can be performed on the generated geometry and the above process repeated. This process will be demonstrated on a variety of geometries and fluid applications with various constraints. A final CFD simulation validates that the design meets the performance requirements.
CFD, Fields, Optimization, Implicit
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