scholarly journals TOMARES

2021 ◽  
Author(s):  
Laura Malena Lottes ◽  
Nils Kaiser ◽  
Nils Goossens ◽  
Holger W. Oelze ◽  
Claus Braxmaier
Keyword(s):  
Finite Element ◽  
Angular Momentum ◽  
Topology Optimization ◽  
Energy Density ◽  
Design Space ◽  
Aerospace Industry ◽  
Reaction Wheel ◽  
Expected Performance ◽  
Payload Mass

AbstractIn aerospace industry, saving mass on spacecrafts always remain in large demand to save launch costs or increase the available payload mass. A case study is carried out designing a first concept of an additive manufactured flywheel of a reaction wheel, as it is one of the heaviest parts of wheel systems. As an objective the mass is minimized, while obtaining an angular momentum suitable according to mission requirements and maintaining recent performances. As references the SeaSAT mission and a commercial reaction wheel are used. The work includes a preliminary dimension of the flywheels design space by MATLAB calculations, where in total 15 shapes are analyzed and compared. The most promising design space is afterwards analyzed via the finite-element tool ANSYS and is defined as the reference flywheel. The reference flywheel is used for topology optimizations (ANSYS Topology Optimization), where different boundary conditions are considered. The final designed flywheel obtains 16% higher energy density than the reference flywheel and withstands the mission loads. It can be concluded that it was possible to design a flywheel obtaining less mass while keeping the expected performance.

Topology and Free Size Optimization With Manufacturing Constraints for Light Weight Die Cast Automotive Backrest Frame

2009 ◽  
Author(s):  
Sreeram Polavarapu ◽  
Lonny L. Thompson ◽  
Mica Grujicic
Keyword(s):  
Finite Element ◽  
Topology Optimization ◽  
Design Space ◽  
Size Optimization ◽  
Manufacturing Constraints ◽  
Material Distribution ◽  
Front Seat ◽  
Die Cast ◽  
Stiffening Ribs ◽  
Multiple Load

Finite element analysis, together with topology and free-size optimization is used to design a lightweight die cast automotive front seat backrest frame when subjected to loads prescribed by ECE R17 European government regulations and additional loads which are predicted in an event of crash. In particular, an effort is made here to study the characteristics of a die cast automotive front seat backrest frame and develop a method for predicting the optimized material and support rib distribution which provides a lightweight seat which satisfies both strength and deflection requirements in a design space which includes the action of multiple load cases. An existing commercially available die cast backrest frame serves as the reference design space. Both 3D surface and solid models are created for representation as shell and solid finite element models for analysis. The objective function for topology optimization of the 3D solid model is to minimize mass of the component subject to stress and deflection constraints and is used as a guide in determining optimal geometric distribution of stiffening ribs. When the shell model of the reference seat is subjected to free-size optimization with this same constraint and objective given, an optimized material distribution measured by shell element thicknesses is obtained. For the topology optimization, manufacturing constraints of preferred draw direction and symmetry are applied in order to obtain an optimized material distribution which can be manufactured in the die-cast process. The procedure followed in this work generated an optimal material distribution and stiffening ribs in a lightweight die cast automotive seat backrest frame when subjected to multiple load cases. An overall reduction in weight of 13% is achieved over a reference commercially available die cast backrest frame component.

scholarly journals Comparative Study of Peridynamics and Finite Element Method for Practical Modeling of Defects Cracks in Topology Optimization

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1407
Author(s):  
Peyman Lahe Motlagh ◽  
Adnan Kefal
Keyword(s):  
Finite Element ◽  
Topology Optimization ◽  
Comparative Study ◽  
Strain Energy ◽  
Optimality Criteria ◽  
Design Stage ◽  
Design Domain ◽  
Optimum Topology ◽  
Strain Stress

Recently, topology optimization of structures with cracks becomes an important topic for avoiding manufacturing defects at the design stage. This paper presents a comprehensive comparative study of peridynamics-based topology optimization method (PD-TO) and classical finite element topology optimization approach (FEM-TO) for designing lightweight structures with/without cracks. Peridynamics (PD) is a robust and accurate non-local theory that can overcome various difficulties of classical continuum mechanics for dealing with crack modeling and its propagation analysis. To implement the PD-TO in this study, bond-based approach is coupled with optimality criteria method. This methodology is applicable to topology optimization of structures with any symmetric/asymmetric distribution of cracks under general boundary conditions. For comparison, optimality criteria approach is also employed in the FEM-TO process, and then topology optimization of four different structures with/without cracks are investigated. After that, strain energy and displacement results are compared between PD-TO and FEM-TO methods. For design domain without cracks, it is observed that PD and FEM algorithms provide very close optimum topologies with a negligibly small percent difference in the results. After this validation step, each case study is solved by integrating the cracks in the design domain as well. According to the simulation results, PD-TO always provides a lower strain energy than FEM-TO for optimum topology of cracked structures. In addition, the PD-TO methodology ensures a better design of stiffer supports in the areas of cracks as compared to FEM-TO. Furthermore, in the final case study, an intended crack with a symmetrically designed size and location is embedded in the design domain to minimize the strain energy of optimum topology through PD-TO analysis. It is demonstrated that hot-spot strain/stress regions of the pristine structure are the most effective areas to locate the designed cracks for effective redistribution of strain/stress during topology optimization.

Topology Optimization of Frame of Aircraft Deicing Vehicle under Multiple Loading Conditions Based on Ansys

2013 ◽  
Vol 760-762 ◽  
pp. 2006-2009
Author(s):  
Min Yuan ◽  
Chong Chen ◽  
Ruo Bing Jiao
Keyword(s):  
Finite Element ◽  
Topology Optimization ◽  
Working Conditions ◽  
Design Space ◽  
Loading Conditions ◽  
Multiple Loading

Firstly this article briefly describes the technology of topology optimization. Then the design space of frame of aircraft deicing vehicle is established and the model of finite element is gained by meshing. Loads and DOF constraints are applied based on the analysis of working conditions. The results of topology optimization are attained by calculation. On the basis of aforementioned results, the analysis is made. Finally, this paper makes a summary and outlook.

scholarly journals Simulation-based design of patient-specific femoral locking plate using topology optimization

2017 ◽  
Author(s):  
◽  
Parag Gholawade
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Topology Optimization ◽  
Orthopedic Implants ◽  
Patient Specific ◽  
Element Analysis ◽  
Simulation Based Design ◽  
Expected Performance ◽  
Simulation Based ◽  
Traditional Approaches

Femoral locking plates are orthopedic implants used in closed reduction of the fractured femur. These orthopedic implants designed using conventional methods apply finite element analysis to evaluate their performance. These traditional approaches result in failure of implants and need for revision surgery. Designing a patient-specific or a customised implant can make a substantial difference to the expected performance response and reduce the failure or breakage of implant. Therefore, a simulation-based design approach is employed which encompasses medical imaging segmentation, finite element analysis, Taguchi design methodology and topology optimization. The intent is to provide a methodology that will help surgeons to make informed decisions backed by engineering analysis.

scholarly journals Stability charts based on the finite element method for underground cavities in soft carbonate rocks: validation through case-study applications

2019 ◽  
Vol 19 (10) ◽  
pp. 2079-2095 ◽  
Author(s):  
Michele Perrotti ◽  
Piernicola Lollino ◽  
Nunzio Luciano Fazio ◽  
Mario Parise
Keyword(s):  
Finite Element ◽  
Safety Margin ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Geometrical Features ◽  
Overall Stability ◽  
Underground Cavities ◽  
The Stability ◽  
Rock Mechanical Properties

Abstract. The stability of man-made underground cavities in soft rocks interacting with overlying structures and infrastructures represents a challenging problem to be faced. Based upon the results of a large number of parametric two-dimensional (2-D) finite-element analyses of ideal cases of underground cavities, accounting for the variability both cave geometrical features and rock mechanical properties, specific charts have been recently proposed in the literature to assess at a preliminary stage the stability of the cavities. The purpose of the present paper is to validate the efficacy of the stability charts through the application to several case studies of underground cavities, considering both quarries collapsed in the past and quarries still stable. The stability graphs proposed by Perrotti et al. (2018) can be useful to evaluate, in a preliminary way, a safety margin for cavities that have not reached failure and to detect indications of predisposition to local or general instability phenomena. Alternatively, for sinkholes that already occurred, the graphs may be useful in identifying the conditions that led to the collapse, highlighting the importance of some structural elements (as pillars and internal walls) on the overall stability of the quarry system.

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