scholarly journals Dynamic Lifecycle Cost Modeling for Adaptable Design Optimization of Additively Remanufactured Aeroengine Components

Aerospace ◽  
2020 ◽  
Vol 7 (8) ◽  
pp. 110 ◽  
Author(s):  
Lydia Lawand ◽  
Massimo Panarotto ◽  
Petter Andersson ◽  
Ola Isaksson ◽  
Michael Kokkolaras
Keyword(s):  
Additive Manufacturing ◽  
Design Optimization ◽  
Optimization Problem ◽  
Problem Formulation ◽  
Cost Modeling ◽  
Costs And Benefits ◽  
Adaptable Design ◽  
Nested Design ◽  
Aeroengine Components ◽  
Optimization Problem Formulation

Additive manufacturing (AM) is being used increasingly for repair and remanufacturing of aeroengine components. This enables the consideration of a design margin approach to satisfy changing requirements, in which component lifespan can be optimized for different lifecycle scenarios. This paradigm requires lifecycle cost (LCC) modeling; however, the LCC models available in the literature consider mostly the manufacturing of a component, not its repair or remanufacturing. There is thus a need for an LCC model that can consider AM for repair/remanufacturing to quantify corresponding costs and benefits. This paper presents a dynamic LCC model that estimates cumulative costs over the in-service phase and a nested design optimization problem formulation that determines the optimal component lifespan range to minimize overall cost while maximizing performance. The developed methodology is demonstrated by means of an aeroengine turbine rear structure.

scholarly journals Optimization-Based Formulations for Short-Circuit Studies with Inverter-Interfaced Generation in PowerModelsProtection.jl

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2160
Author(s):  
Arthur K. Barnes ◽  
Jose E. Tabarez ◽  
Adam Mate ◽  
Russell W. Bent
Keyword(s):  
Optimization Problem ◽  
Short Circuit ◽  
Problem Formulation ◽  
Power Delivery ◽  
Fault Current ◽  
Protective Device ◽  
Protective Relaying ◽  
Overcurrent Protection ◽  
Short Circuits ◽  
Optimization Problem Formulation

Protecting inverter-interfaced microgrids is challenging as conventional time-overcurrent protection becomes unusable due to the lack of fault current. There is a great need for novel protective relaying methods that enable the application of protection coordination on microgrids, thereby allowing for microgrids with larger areas and numbers of loads while not compromising reliable power delivery. Tools for modeling and analyzing such microgrids under fault conditions are necessary in order to help design such protective relaying and operate microgrids in a configuration that can be protected, though there is currently a lack of tools applicable to inverter-interfaced microgrids. This paper introduces the concept of applying an optimization problem formulation to the topic of inverter-interfaced microgrid fault modeling, and discusses how it can be employed both for simulating short-circuits and as a set of constraints for optimal microgrid operation to ensure protective device coordination.

Optimization Problem Formulation

2016 ◽  
pp. 47-61
Author(s):  
Javier Contreras ◽  
Miguel Asensio ◽  
Pilar Meneses de Quevedo ◽  
Gregorio Muñoz-Delgado ◽  
Sergio Montoya-Bueno
Keyword(s):  
Optimization Problem ◽  
Problem Formulation ◽  
Optimization Problem Formulation

Predictive Control of a Laboratory Time Delay Process Experiment

2013 ◽  
Vol 11 (1) ◽  
pp. 29-36
Author(s):  
S. Enev
Keyword(s):  
Time Delay ◽  
Predictive Control ◽  
Control Algorithm ◽  
Optimization Problem ◽  
Problem Formulation ◽  
Practical Implementation ◽  
Control Law ◽  
Design And Implementation ◽  
Optimization Problem Formulation ◽  
Laboratory Time

Abstract The paper presents the design and implementation of a Model Predictive Control (MPC) scheme of a laboratory heatexchange process with a significant time delay in the input-output path. The optimization problem formulation is given and an MPC control algorithm is designed, achieving integral properties. Details, related to the practical implementation of the control law are discussed and the first experimental results are presented.

A nonlinear optimization shooting method for bifurcation tracking of nonlinear systems

2020 ◽  
pp. 107754632095674
Author(s):  
Haitao Liao ◽  
Mengyu Li ◽  
Ruxin Gao
Keyword(s):  
Periodic Solution ◽  
Optimization Problem ◽  
Continuation Method ◽  
Problem Formulation ◽  
Correlation Equation ◽  
Jeffcott Rotor ◽  
Optimization Formulation ◽  
Bifurcation Detection ◽  
Tuned Vibration Absorber ◽  
Optimization Problem Formulation

A continuation method for bifurcation tracking is presented based on the proposed optimization problem formulation which is designed to locate the bifurcation periodic solution. The bifurcation detection problem is formulated as a constrained optimization problem. The nonlinear constraints of the optimization problem are imposed on the shooting function and bifurcation conditions derived from the Floquet theory whereas the objective function associated with the pseudo-arclength correlation equation is devised to solution continuation. The proposed optimization formulation is integrated with the prediction–correction strategy to achieve bifurcation tracking. Two numerical examples about the Jeffcott rotor and the nonlinear tuned vibration absorber are illustrated to validate the effectiveness of the proposed methodology. Numerical results have demonstrated that the proposed method offers a convenient scheme to follow bifurcation periodic solution.

Design of Compliant Mechanical Amplifiers for Piezoceramic Stack Actuators Considering Stiffness Properties

2000 ◽  
Author(s):  
Mary Frecker ◽  
Shawn Canfield
Keyword(s):  
Optimization Problem ◽  
Piezoelectric Properties ◽  
Compliant Mechanism ◽  
Problem Formulation ◽  
Optimization Method ◽  
Unit Load ◽  
Coupling Structure ◽  
Stiffness Properties ◽  
Constant Unit ◽  
Optimization Problem Formulation

Abstract A topology optimization method for design of compliant mechanical amplifiers for piezoceramic stack actuators is presented. Previously the optimization was done assuming that the stack actuator provided a constant unit load to the compliant mechanism. However, it is well known that the best actuator performance occurs when the stiffness of the stack is considered and matches the stiffness of the surrounding coupling structure. In this paper an improved formulation is presented where the piezoelectric properties and stiffness of the stack are included along with an external spring representing a resisting load the actuator is working against. The optimization problem formulation, finite element implementation, solution algorithm are discussed. Two design examples are presented which illustrate the effect of the stiffness of the external spring and the size of the design domain on the topology of the solution.

scholarly journals Optimization problem formulation framework with application to engineering systems

2017 ◽  
Vol 20 (6) ◽  
pp. 512-528
Author(s):  
William A. Crossley ◽  
Siyao Luan ◽  
James T. Allison ◽  
Deborah L. Thurston
Keyword(s):  
Optimization Problem ◽  
Problem Formulation ◽  
Engineering Systems ◽  
Optimization Problem Formulation
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