scholarly journals Optimal Design and Design Parameter Sensitivity Analyses of an eVTOL PAV in the Conceptual Design Phase

2020 ◽  
Vol 10 (15) ◽  
pp. 5112 ◽  
Author(s):  
Bong-Sul Lee ◽  
Abera Tullu ◽  
Ho-Yon Hwang

An optimization study of an electric vertical takeoff and landing personal air vehicle (eVTOL PAV) was performed during the conceptual design stage using the design of experiments method. In defining the initial problem, a design target parameter was set. The PAV subsystem was based on a configuration tradeoff study matrix, which was used to effectively conduct configuration selection. Initial sizing was performed using the PAV sizing program developed by this research team using Microsoft Excel and Visual Basic for Application (VBA). A screening test was performed to find parameters with high sensitivity among independent design parameters. The response surface method was used to model design target parameters, and a regression equation was estimated using the experimental design method. A Monte Carlo simulation was performed to confirm the feasibility of the generated model. To optimize the design independent parameter, a satisfaction function was selected, and the appropriateness of the data was determined using a Pareto plot and p-value.

Author(s):  
Hyunwoong Ko ◽  
Seung Ki Moon

Additive Manufacturing (AM)’s advance from rapid prototyping to the end-of-use products inevitably challenges conventional design theories and methodologies. Especially while adopting systematic engineering design methodologies to design for AM (DfAM), it is essential to develop new design methods that explore the new design space enabled by AM’s design freedom from the early design stage. To address the challenge, this study provides a new design framework and a design method for modeling AM-enabled product behaviors in the conceptual design phase of DfAM. Firstly, this study contrasts function-based methods with affordance-based methods. The device-centric, form independent and input/output-based transformative properties of the function-based methods such as function decompositions have strengths in modeling product’s internal behaviors. However, the function-based methods show limitations in the new area of AM-enabled mass personalization which requires design approaches for representing user-centric structural design requirements acquired only by AM’s design freedom. On the other hand, the affordance-based methods can address the function-based methods in DfAM due to their user-centric (artifact-user interactive), form dependent and non-transformative properties. After the contradiction, we propose an affordance-based DfAM framework and an affordance structure as a formal modeling technique for AM-enabled personalized product behaviors. A case study of a trans-tibial prosthesis socket provides an illustration in this study. The contribution of the study is in developing a design method for the conceptual design phase of DfAM that fulfills the objectives of achieving AM-enabled mass personalization with systematic engineering design approaches.


2016 ◽  
Vol 826 ◽  
pp. 40-44 ◽  
Author(s):  
Fei Cao ◽  
Ming Chen ◽  
Mei Li Wen Wu

The purpose of this paper is to study the conceptual design and optimization of a compound coaxial helicopter. At the conceptual design phase, the compound coaxial helicopter design work was based on the conventional helicopter and fix-wing aircraft design method. The intersection of these aspects makes the design work more complex, thus, a program for the sizing and performance optimization was developed for the aircraft. The program included the total weight design, aerodynamic analysis, flight dynamics analysis, performance calculation and particle swarm optimization analysis. Under the restricted condition of the flight performance requirements, optimize the design parameters which make the weight efficiency factor decrease. Therefore, the study of optimum design process was warranted.


2015 ◽  
Vol 761 ◽  
pp. 63-67 ◽  
Author(s):  
Muhd Ridzuan Mansor ◽  
S.M. Sapuan ◽  
A. Hambali ◽  
Edi Syam Zainudin ◽  
A.A. Nuraini

Spoilers are part of an automotive exterior bodywork system that acts to create additional down force for higher traction. In this paper, a new conceptual design of automotive spoiler component using kenaf polymer composites was developed using integrated TRIZ and morphology chart design method. The aim is to enable direct application of kenaf polymer composites to the spoiler design to achieve better environmental performance of the component while maintaining the required structural strength for safe and functional operation. The overall process involved two major stages, which are the idea generation and concept development. TRIZ method was applied in the idea generation stage where specific solution strategies for the design were created. In the concept development stage, the specific TRIZ solution strategies obtained were later refined into relevant alternative system elements using Morphology chart method. Finally, a new conceptual design of an automotive spoiler was developed using the combination of the identified system elements. The integrated TRIZ and morphology chart method were found to be new tools that can be used effectively in the concept design stage, especially in cases where direct material substitution is given the main focus for the new product development.


Author(s):  
Ryan S. Hutcheson ◽  
Irem Y. Tumer

NASA’s Ames Research center is currently designing a testbed to validate and compare potential Integrated System Health Management (ISHM) technologies. The proposed testbed represents a typical power system for a spacecraft and includes components such as a fuel cell, solar cells and redundant batteries. To fulfill design requirements, the testbed must be capable of hosting a wide variety of ISHM technologies including those developed by NASA as well as those developed in the aerospace industry abroad. An internal fault injection subsystem must be built into the system to provide a common interface for evaluating these different ISHM technologies. Additionally, to ensure robust operation of the testbed, the capability to detect and manage external faults must also be present. In order to develop a set of requirements for the internal fault injection subsystems as well as predict external faults, a comprehensive set of potential failures must be identified for all of the components of the testbed. To best aid the development of the testbed, these failures needed to be identified as early as the conceptual design phase, where little is known about the actual components that would comprise the finished system. This paper demonstrates the use a function-based failure mode identification method to identify the potential failures of the testbed during the conceptual design phase. Using this approach, designers can explore the potential failure modes at the functional design stage, before a form or solution has been determined. A function-failure database is used to associate the failures of components from previous design efforts to the testbed based on common functionality. The result is a list of potential failure modes and associated failure rates, which are used to improve the design of the testbed as well as provide a framework for the fault injection subsystem.


2011 ◽  
Vol 199-200 ◽  
pp. 583-586
Author(s):  
Yu Lian Cui ◽  
Wei Wu

In this paper an attempt has been made to identify certain useful parts that will assist to consider reliability during conceptual design phase. The aim is to provide some thoughts and a toolkit for addressing reliability during the early stages of design, influencing design decisions and product reliability, and reducing the relying on the reliability prediction and expensive experiments in later design stage. Therefore high reliability can be cost-effectively achieved.


2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Toru Matsushima ◽  
Kazuhiro Izui ◽  
Shinji Nishiwaki

Minimizing brake squeal is one of the most important issues in the development of high performance braking systems. Furthermore, brake squeal occurs due to the changes in unpredictable factors such as the friction coefficient, contact stiffness, and pressure distribution along the contact surfaces of the brake disk and brake pads. This paper proposes a conceptual design method for disk brake systems that specifically aims to reduce the occurrence of low frequency brake squeal at frequencies below 5 kHz by appropriately modifying the shapes of brake system components to obtain designs that are robust against changes in the above unpredictable factors. A design example is provided and the validity of the obtained optimal solutions is then verified through real-world experiments. The proposed optimization method can provide useful design information at the conceptual design stage during the development of robust disk brake systems that maximize the performance while minimizing the occurrence of brake squeal despite the presence of unpredictable usage factors.


Author(s):  
Jo Köhler ◽  
Peter Jeschke

AbstractThis paper presents a novel conceptual design method for electric and hybrid electric propulsion systems in small aircraft. The effects of key design parameters on the propulsion system performance are analyzed and the advantages and drawbacks of the investigated propulsion systems are discussed on the basis of two sets of thrust requirements. First, the general conceptual design algorithm is outlined. This is followed by a description of the three propulsion systems investigated: the fully electric; the parallel hybrid; and the conventional internal combustion engine. Scalable models of all required propulsion system components are presented, including weight estimation and operating characteristics. Afterwards, the conceptual design algorithm is exemplified for a reference two-seater motorized glider with a cruising speed of 140 kt and a maximum take-off mass of 1000 kg. Key design parameters are identified and their impact on propulsion system mass and cruise efficiency discussed. This study suggests that the parallel hybrid propulsion system is advantageous for high power ratios between take-off and cruise. For a power ratio of 4.5, either a relative cruise efficiency advantage of 12% or a maximum system mass advantage of 10% can be expected, depending on the propeller design. For the chosen cruise range of 300 km, the system mass of the fully electric propulsion system is at least 2.37 times higher when compared to the conventional propulsion system. In summary, a design method for hybrid electric propulsion systems is presented here which may be used for conceptual design. Furthermore, the suitability of the propulsion systems under investigation for different sets of thrust requirements is assessed, which may be helpful for aircraft designers.


1970 ◽  
Vol 14 (01) ◽  
pp. 52-65
Author(s):  
G. Kuiper

A description is given of a mathematical representation of the ship's hull. The ship form can be given by a number of parameters, which are connected with the usual design parameters of a lines plan. Some qualitative design parameters such as U-or V-shaped sections can be formulated numerically. A design method is given which does not need more information than available at the preliminary design stage. Some results and variations are presented.


2011 ◽  
Vol 328-330 ◽  
pp. 232-236
Author(s):  
Lian Zhong Guo ◽  
Ding Yang ◽  
Zi Teng Huang

The purpose of this work is to present an optimal design method for radar brackets to get the lightest structure with stiffness constraint. Current radar brackets usually have conservative strength and excessive weight which influences the mobility of radar greatly as they are not optimized in the conceptual design stage. In this paper the well-known ESO (Evolutionary Structural Optimization) method based on ANSYS is studied and used as the method to optimize them. To begin with the criteria of ESO method and its implementation method are studied. Then a case of optimization for a phased array radar bracket is studied and at last the optimization result is compared to the result by using WORKBENCH (a commercial CAE software) and the comparison shows that this method has its unique superiority.


Author(s):  
Michael E. Stock ◽  
Robert B. Stone ◽  
Irem Y. Tumer

In today’s world it is more important than ever to quickly and accurately satisfy customer needs when launching a new product. It is equally important to design products that adequately accomplish their desired functions with a minimum amount of failures. When failure analysis and prevention are coupled with a product design from its conception, shorter design times and fewer redesigns are necessary to arrive at a final product design. In this article, we explore the potential of a novel design methodology to guide designers toward new designs or redesigns that avoid failures. The Elemental Function-Failure Design Method (EFDM) is based on functional similarity of the product being designed to failed products within a knowledge base. The idea of using component functionality to explore the failure space in design was first introduced as a function-failure analysis approach by Tumer and Stone (2003). The overall approach offers potential improvement over current failure analysis methods (FMEA, etc.), because it can be implemented hand in hand with other conceptual design steps and carried throughout a product’s design cycle. In this paper, this idea is formalized into a systematic methodology that is specifically tailored for use at the conceptual design stage before any physical design choices have been made, hence moving failure analysis earlier in the design cycle. In the following, formalized guidelines for using the EFDM will be outlined for use in new designs and for redesign in existing products. A function-failure knowledge base, derived from actual failure occurrences for Bell 206 rotorcraft will be introduced and used to derive potential failure modes in a comparison of the EFDM and traditional FMEA for two design examples. This comparison will demonstrate the EFDM’s potential in conceptual design failure analysis.


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