A Non-Deterministic Approach to Concept Selection Using S-Pareto Frontiers

2002 ◽  
Author(s):  
Christopher A. Mattson ◽  
Achille Messac
Keyword(s):  
Design Parameters ◽  
Concept Selection ◽  
Traditional Use ◽  
Design Decisions ◽  
Traditional Concept ◽  
Critical Design ◽  
Model Fidelity ◽  
Engineering Design Process ◽  
Definition Of ◽  
Pareto Frontiers

The most significant design decisions are typically made during the conceptual phase of the engineering design process, when critical design features are proposed, evaluated and selected. In this paper, we explore the critical task of concept selection and propose a non-deterministic, optimization-based approach for selecting the most promising concept. The method presented in this paper builds upon the recently-proposed s-Pareto based concept selection approach. Within the framework of the s-Pareto approach, so-called s-Pareto frontiers are obtained by using the definition of Pareto optimality to identify Pareto optimal solutions that pertain to a set of distinct concepts. These s-Pareto frontiers are used to assess the tradeoffs between various proposed concepts during conceptual design. The s-Pareto approach is a marked departure from traditional concept selection methods and from the traditional use of Pareto frontiers. In this work the s-Pareto approach is extended to include uncertainties caused by stochastic design parameters as well as low model fidelity. More specifically, the reliability of design decisions is accounted for in the decision-making process. Two approaches are presented for performing non-deterministic concept selection. Two examples are given that support the approach.

A New Hooked Needle Device For Forming Fiber Beards For Length and Strength Measurement

1978 ◽  
Vol 100 (1) ◽  
pp. 5-7
Author(s):  
R. L. Barker ◽  
H. W. Poole ◽  
D. W. Lyons
Keyword(s):  
Cotton Fiber ◽  
Automated Analysis ◽  
Design Parameters ◽  
Strength Testing ◽  
Design Development ◽  
Strength Measurement ◽  
Visual Appearance ◽  
Critical Design ◽  
Thin Profile ◽  
Definition Of

Research was conducted in the design, development, and evaluation of a new hooked needle device for obtaining from a sample of cotton a parallelized beard of fiber suitable for instrumented length and strength testing. Through systematic definition of critical design parameters, needle combs were developed capable of forming thin profile fiber beards of exceptional uniformity and visual appearance. The acceptability of a hooked needle method for preparing beards of cotton fiber for automated analysis was demonstrated as this device was compared with conventional clamp and comb arrangements of fiber sampling.

scholarly journals NOVICE DESIGNERS' USE OF PROTOTYPES AS COMMUNICATION TOOLS

2021 ◽  
Vol 1 ◽  
pp. 2277-2286
Author(s):  
Sandeep Krishnakumar ◽  
Carlye Lauff ◽  
Christopher McComb ◽  
Catherine Berdanier ◽  
Jessica Menold
Keyword(s):  
Adverse Outcomes ◽  
Design Teams ◽  
Prior Work ◽  
Communication Tools ◽  
Design Decisions ◽  
Pedagogical Strategies ◽  
Critical Design ◽  
Undergraduate Engineering ◽  
Novice Designers ◽  
Future Work

AbstractPrototypes are critical design artifacts, and recent studies have established the ability of prototypes to facilitate communication. However, prior work suggests that novice designers often fail to perceive prototypes as effective communication tools, and struggle to rationalize design decisions made during prototyping tasks. To understand the interactions between communication and prototypes, design pitches from 40 undergraduate engineering design teams were collected and qualitatively analysed. Our findings suggest that students used prototypes to explain and persuade, aligning with prior studies of design practitioners. The results also suggest that students tend to use prototypes to justify design decisions and adverse outcomes. Future work will seek to understand novice designers’ use of prototypes as communication tools in further depth. Ultimately, this work will inform the creation of pedagogical strategies to provide students with the skills needed to effectively communicate design solutions and intent.

scholarly journals CONCEPTUAL DESIGN FOR ASSEMBLY IN AEROSPACE INDUSTRY: SENSITIVITY ANALYSIS OF MATHEMATICAL FRAMEWORK AND DESIGN PARAMETERS

2021 ◽  
Vol 1 ◽  
pp. 731-740
Author(s):  
Giovanni Formentini ◽  
Claudio Favi ◽  
Claude Cuiller ◽  
Pierre-Eric Dereux ◽  
Francois Bouissiere ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Conceptual Design ◽  
Design Parameters ◽  
Design For Assembly ◽  
Mathematical Framework ◽  
Commercial Aircraft ◽  
System Architectures ◽  
Complex Engineering ◽  
Aircraft System ◽  
Definition Of

AbstractOne of the most challenging activity in the engineering design process is the definition of a framework (model and parameters) for the characterization of specific processes such as installation and assembly. Aircraft system architectures are complex structures used to understand relation among elements (modules) inside an aircraft and its evaluation is one of the first activity since the conceptual design. The assessment of aircraft architectures, from the assembly perspective, requires parameter identification as well as the definition of the overall analysis framework (i.e., mathematical models, equations).The paper aims at the analysis of a mathematical framework (structure, equations and parameters) developed to assess the fit for assembly performances of aircraft system architectures by the mean of sensitivity analysis (One-Factor-At-Time method). The sensitivity analysis was performed on a complex engineering framework, i.e. the Conceptual Design for Assembly (CDfA) methodology, which is characterized by level, domains and attributes (parameters). A commercial aircraft cabin system was used as a case study to understand the use of different mathematical operators as well as the way to cluster attributes.

Root cause analysis of rattle noise in twin-tube vehicle dampers

2021 ◽  
pp. 095440702110652
Author(s):  
Marian Sikora ◽  
Janusz Gołdasz
Keyword(s):  
Design Of Experiment ◽  
Ride Comfort ◽  
Design Parameters ◽  
Vehicle Suspension ◽  
Experiment Study ◽  
Cause Analysis ◽  
Root Cause ◽  
Main Effect ◽  
Definition Of ◽  
Insight Into

The aim of this work is to provide an insight into the rattle noise phenomena occurring in double-tube (twin-tube) vehicle suspension dampers. In the dampers the particular phenomenon results from interactions between the valve(s) and the fluid passing through them. The rattling noise phenomena is known to degrade the vehicle passenger’s perception of ride comfort as well as to influence the performance of the dampers at low and medium speeds in particular. In the paper the authors reveal the results of a DOE (Design of Experiment) study involving several design parameters known to affect rattling occurrence. By running a series of purpose-designed tests the authors investigate not only the contribution of each particular parameter but the interactions between them. The results are presented in the form of pareto charts, main effect plots as well as interaction plots. It is expected the outcome of the analysis will aid in a better comprehension of the phenomena as well the definition of valve configurations to minimize their performance degradation.

scholarly journals METHODS OF CFD MODELLING OF TWIN-SCREW PUMPS FOR NON-NEWTONIAN MATERIALS

2021 ◽  
Vol 2021 (6) ◽  
pp. 5366-5372
Author(s):  
MARIAN BOJKO ◽  
◽  
LUKAS HERTL ◽  
SYLVA DRABKOVA ◽  
◽  
...  
Keyword(s):  
Power Law ◽  
Food Industry ◽  
3D Model ◽  
Design Parameters ◽  
Cfd Modelling ◽  
Ansys Fluent ◽  
Screw Pump ◽  
Twin Screw ◽  
Definition Of ◽  
Power Law Parameters

The twin-screw pump is designed for pumping highly viscous materials in the food industry. Rheological characteristics of materials are important in the specification of design parameters of screw pumps. Analysis of flow in the twin-screw pumps with definition of non-newtonian materials can be made by numerical modelling. CFD generally oriented software ANSYS Fluent and ANSYS Polyflow has been used for modelling. In this study those software’s (ANSYS Fluent and ANSYS Polyflow) were defined for solution of flow in the twin-screw pumps. Results were compared for the same boundary conditions on the inlet and outlet of the 3D model. For definition of the viscosity were used the Nonnewtonian power law. Parameters as consistency coefficient and flow exponent for Nonnewtonian power law were analysed by software ANSYS Fluent and ANSYS Polyflow. Postprocessing form ANSYS Fluent and ANSYS Polyflow were made by contours of field and by graphs.

scholarly journals Early Robust Design—Its Effect on Parameter and Tolerance Optimization

2021 ◽  
Vol 11 (20) ◽  
pp. 9407
Author(s):  
Stefan Goetz ◽  
Martin Roth ◽  
Benjamin Schleich
Keyword(s):  
Product Development ◽  
Robust Design ◽  
Product Development Process ◽  
Design Parameters ◽  
Concept Design ◽  
Design Decisions ◽  
Dynamic Markets ◽  
Tolerance Optimization ◽  
Qualitative Approaches ◽  
Design Activities

The development of complex products with high quality in dynamic markets requires appropriate robust design and tolerancing workflows supporting the entire product development process. Despite the large number of methods and tools available for designers and tolerance engineers, there are hardly any consistent approaches that are applicable throughout all development stages. This is mainly due to the break between the primarily qualitative approaches for the concept stage and the quantitative parameter and tolerance design activities in subsequent stages. Motivated by this, this paper bridges the gap between these two different views by contrasting the used terminology and methods. Moreover, it studies the effects of early robust design decisions with a focus on Suh’s Axiomatic Design axioms on later parameter and tolerance optimization. Since most robust design activities in concept design can be ascribed to these axioms, this allows reliable statements about the specific benefits of early robust design decisions on the entire process considering variation in product development for the first time. The presented effects on the optimization of nominal design parameters and their tolerance values are shown by means of a case study based on ski bindings.

Estimating Errors in Concept Selection

1995 ◽  
Author(s):  
K. N. Otto ◽  
Kristin L. Wood
Keyword(s):  
Error Propagation ◽  
Final Decision ◽  
Selection Methods ◽  
Concept Selection ◽  
Confidence Measure ◽  
Critical Design ◽  
Fundamental Causes ◽  
Design Alternatives ◽  
Degree Of Confidence ◽  
Numerical Concept

Abstract Numerical concept selection methods are used throughout industry to determine which among several design alternatives should be further developed. The results, however, are rarely believed at face value. Uncertainties (or errors) in subjective choices, modeling assumptions, and measurement are fundamental causes of this disbelief. This paper describes a methodology developed to predict overall error ranges, in addition to estimating a confidence measure in the numerical evaluation results. Each numerical assignment is given an associated error tolerance, and then treated as a probability error to create a simple means to propagate the uncertainties. A degree of confidence is also derived, similar to a statistical t-test, to indicate an induced confidence level in the final decision. Two preliminary concept selections are shown, to illustrate the methodology. Results from these concept selections indicate that (1) uncertainties can be suitably captured and quantified; (2) critical design questions are addressed during the process of numerical concept selection with error propagation; and (3) designers can make more informed and confident decisions through error estimation.

Design Quality and Reliability Through Technology Readiness

1989 ◽  
Author(s):  
J. Fox
Keyword(s):  
Product Launch ◽  
Design Parameters ◽  
Technology Readiness ◽  
Design Quality ◽  
Critical Design ◽  
Early Stages ◽  
Product Delivery ◽  
Quality And Reliability ◽  
The Relationship

Abstract This paper discusses the relationship between the growth of reliability in the early stages of a product delivery process and Technology Readiness, and describes the importance of ‘ready’ technologies if product launch schedules are to be achieved. Technology Readiness itself is defined and the enablers for it are identified. A process which has been developed is described, and some proposals for tracking and managing progress are made. Finally, the importance of critical design parameters both in the development of technologies and in understanding technology capabilities are described fully.

Steam Turbine Overspeed Scenarios: Comparison Between API Energy Method and Dynamic Simulation

2021 ◽  
Author(s):  
Fabrizio Piras ◽  
Federico Bucciarelli ◽  
Damaso Checcacci ◽  
Filippo Ingrasciotta
Keyword(s):  
Design Parameters ◽  
Steam Turbines ◽  
Analysis Method ◽  
Design Constraint ◽  
Rotating Speed ◽  
Critical Design ◽  
Operating Stress ◽  
Technological Challenge ◽  
Rotor Dynamic ◽  
Peak Value

Abstract In turbomachinery applications the possibility to reduce size and costs of main flow-path components, by increasing shaft rotating speed, has always been appealing. The technological challenge in increasing this power density capability is typically related to performance prediction, to operating stress in blades and shafts, as well as to the need for a more accurate rotor-dynamic analysis. Yet another aspect, often reduced to standard assessments in less demanding applications, is related to the analysis of overspeed scenarios where, following a sudden loss of load and/or driven inertia, the turbomachine shall maintain its mechanical integrity. Especially in steam turbines applications, where the behavior of the machine is strongly affected by the plant conditions, valves intervention time and connected volumes, the reduction of the rotor inertia, against comparable power, may produce overspeed scenarios that can become a primary design constraint and, if overlooked, may have both availability and safety implications. In this paper several approaches to the analysis of overspeed scenarios are discussed, with increasing level of detail. The energy-based overspeed analysis method, as required by API612, is first discussed against practical design cases. A more accurate dynamic model is then presented, and its results compared with those of the energy-based approach. Finally, the sensitivity analysis of the overspeed peak value with respect to critical design parameters is discussed. With respect to previous works, mostly based on load rejection scenarios, the main focus is on the scenario of sudden coupling loss.

Sign in / Sign up

Export Citation Format

Share Document