scholarly journals Decomposition-Based Assembly Synthesis for In-Process Dimensional Adjustability

2002 ◽  
Author(s):  
Byungwoo Lee ◽  
Kazuhiro Saitou
Keyword(s):  
Design Process ◽  
Early Stage ◽  
Product Configuration ◽  
Two Dimensional ◽  
Design Phase ◽  
Assembly Design ◽  
Component Design ◽  
Assembly Sequences ◽  
Simple Rules ◽  
Final Design

This paper presents a method of assembly synthesis focused on the in-process adjustability, where assembly synthesis is defined as the decomposition of the end product design prior to the detailed component design phase. Focusing on the effect of joint configurations on dimensional integrity of complex assemblies, the method recursively decomposes a product configuration and assigns joint configurations according to simple rules, in order to achieve a designed dimensional adjustability and non-forced fit. The rules employed during the decomposition process are drawn from the previous works of assembly design. An augmented AND/OR graph is utilized to represent a process of assembly synthesis with the corresponding assembly sequences, and the algorithm for generating the AND/OR graph is discussed. The method is applied to two dimensional skeletons of product designs at very early stage of the design process. The relation of the assembly synthesis to Datum Flow Chain (Mantripragada and Whitney, 1998) is discussed. It is also shown that each final design from the assembly synthesis defines its own Datum Flow Chain.

scholarly journals Decomposition-Based Assembly Synthesis for In-Process Dimensional Adjustability

2003 ◽  
Vol 125 (3) ◽  
pp. 464-473 ◽  
Author(s):  
Byungwoo Lee ◽  
Kazuhiro Saitou
Keyword(s):  
Design Process ◽  
Early Stage ◽  
Product Configuration ◽  
Two Dimensional ◽  
Design Phase ◽  
Assembly Design ◽  
Component Design ◽  
Assembly Sequences ◽  
Simple Rules ◽  
Final Design

This paper presents a method of assembly synthesis focused on the in-process adjustability, where assembly synthesis is defined as the decomposition of the end product design prior to the detailed component design phase. Focusing on the effect of joint configurations on dimensional integrity of complex assemblies, the method recursively decomposes a product configuration and assigns joint configurations according to simple rules, in order to achieve a designed dimensional adjustability and non-forced fit. The rules employed during the decomposition process are drawn from the previous works of assembly design. An augmented AND/OR graph is utilized to represent a process of assembly synthesis with the corresponding assembly sequences, and the algorithm for generating the AND/OR graph is discussed. The method is applied to two dimensional skeletons of products without moving parts at very early stage of the design process. The relation of the assembly synthesis to Datum Flow Chain [1] is discussed. It is also shown that each final design from the assembly synthesis defines its own Datum Flow Chain.

The Datum Flow Chain: A Systematic Approach to Assembly Design and Modeling

1998 ◽  
Author(s):  
R. Mantripragada ◽  
D. E. Whitney
Keyword(s):  
Design Process ◽  
Systematic Approach ◽  
Assembly Planning ◽  
Assembly Process ◽  
Top Down ◽  
Assembly Design ◽  
Key Characteristics ◽  
Assembly Sequences

Abstract In order to be able to lay out, analyze, outsource, assemble, and debug complex assemblies, we need ways to capture their fundamental structure in a top-down design process, including the designer’s strategy for kinematically constraining and locating the parts accurately with respect to each other. We describe a concept called the “Datum Flow Chain” to capture this logic. The DFC relates the datum logic explicitly to the product’s key characteristics, assembly sequences, and choice of mating features, and provides the information needed for tolerance analyses. Two types of assemblies are addressed: Type-1 where the assembly process puts parts together at their prefabricated mating features, and Type-2 where the assembly process can incorporate in-process adjustments to redistribute variation. Two types of assembly joints are defined: mates that pass dimensional constraint from part to part, and contacts that merely provide support. The scope of DFC in assembly planning is presented using several examples. Analysis tools to evaluate different DFCs and select the ones of interest are also presented.

A configuration design based method for platform commonization for product families

2004 ◽  
Vol 18 (1) ◽  
pp. 21-39 ◽  
Author(s):  
BRIAN CORBETT ◽  
DAVID W. ROSEN
Keyword(s):  
Design Space ◽  
Product Family ◽  
Combinatorial Design ◽  
Product Configuration ◽  
Configuration Design ◽  
Design Problems ◽  
Product Families ◽  
Assembly Design ◽  
Assembly Sequences ◽  
Design Requirements

Product families help companies reach customers in several different markets, lessen the time needed to develop new products, and reduce costs by sharing common components among many products. The product platform can be considered as a set of technologies, components, or functions, and their arrangements, that are utilized for more than one product. Configuration design focuses on the components in a product and their connections and relationships. Discrete, combinatorial design spaces are used to model design requirements regarding physical connections, module partitions, and assembly sequences for the product family. To ensure that products satisfy all design requirements, it is necessary to combine these design spaces into a common configuration space into which all requirements can be mapped. This paper presents computational methods for modeling and combining design spaces so those configurations can be identified that satisfy all constraints. A new representation of assembly sequences facilitates the development of an assembly design space, elements of which can be enumerated readily. Because the size of the combinatorial design spaces can become quite large, computational efficiency is an important consideration. A new designer guided method, called the partitioning method, is presented for decomposing configuration design problems in a hierarchical manner that enables significant reductions in design space sizes. An example of a family of automotive underbodies illustrates the application of the discrete design space approach to develop a common platform.

scholarly journals The Influence of Timing in Exploratory Prototyping and Other Activities in Design Projects

2013 ◽  
Author(s):  
Anders Häggman ◽  
Tomonori Honda ◽  
Maria C. Yang
Keyword(s):  
Graduate Students ◽  
Design Process ◽  
Early Stage ◽  
User Interaction ◽  
Preliminary Design ◽  
Design Phase ◽  
Design Activities ◽  
Design Projects

The importance of prototyping in the design process has been widely recognized, but less research emphasis has been placed on the appropriate timing and detail of so-called “throwaway” prototyping during the preliminary design phase. Based on a study of mid-career professional graduate students, statistically significant correlations were found between the time such prototypes were created and design outcome. Building prototypes early on in the design process, or performing additional rounds of benchmarking and user interaction later on during the project (in addition to the typical early stage efforts), correlated with better design outcome, although the total time spent on these activities did not. The correlation between project presentations and reviewer scores are also touched upon. These findings suggest that the timing of design activities is more important than the time spent on them.

scholarly journals Approach for analysis and modeling of reliability of network connectivity from the perspective of efficiency and its applicability

2021 ◽  
Vol 7 ◽  
pp. 57-63
Author(s):  
Tsvetelina Simeonova
Keyword(s):  
Markov Chain ◽  
Early Stage ◽  
Block Diagram ◽  
Network Connectivity ◽  
The Other ◽  
Design Phase ◽  
Qualitative And Quantitative ◽  
Operation And Maintenance ◽  
Component Design ◽  
Influencing Parameters

Reliability analysis and assessment methods can be used at any stage of system or component design, including development, operation, and maintenance. Fault Tree-based models and reliability block diagram RBD (qualitative and quantitative) are typically used to provide reliability and readiness assessments for both the early and later stages of design, where system models are more -improved and have more detailed specifications compared to the models of the early stage of the system. On the other hand, models based on the Markov Chain are mainly used in the later design phase. The aim of the work is to define ways to use methods for modeling reliability, with a subsequent goal for analysis taking into account the effectiveness. An approach for modeling the end-to-end network connectivity with different reservations of the connection lines is considered. The results are illustrated by graphical ratios at different influencing parameters, for different reservation methods. A comparative analysis was made using different reservation methods. The practical applicability of the proposed approach and the performed analysis, incl. for training purposes.

scholarly journals Anisotropic nanocrystal shape and ligand design for co-assembly

2021 ◽  
Vol 7 (23) ◽  
pp. eabf9402
Author(s):  
Katherine C. Elbert ◽  
William Zygmunt ◽  
Thi Vo ◽  
Corbin M. Vara ◽  
Daniel J. Rosen ◽  
...  
Keyword(s):  
Rational Design ◽  
Ligand Design ◽  
Building Blocks ◽  
Two Dimensional ◽  
Secondary System ◽  
Assembly Design ◽  
Ligand Shell ◽  
Powerful Approach ◽  
Anisotropic Systems ◽  
Direct Materials

The use of nanocrystal (NC) building blocks to create metamaterials is a powerful approach to access emergent materials. Given the immense library of materials choices, progress in this area for anisotropic NCs is limited by the lack of co-assembly design principles. Here, we use a rational design approach to guide the co-assembly of two such anisotropic systems. We modulate the removal of geometrical incompatibilities between NCs by tuning the ligand shell, taking advantage of the lock-and-key motifs between emergent shapes of the ligand coating to subvert phase separation. Using a combination of theory, simulation, and experiments, we use our strategy to achieve co-assembly of a binary system of cubes and triangular plates and a secondary system involving two two-dimensional (2D) nanoplates. This theory-guided approach to NC assembly has the potential to direct materials choices for targeted binary co-assembly.

Bringing Ergonomics to the Design of a Behavioural Care Unit

2000 ◽  
Vol 44 (8) ◽  
pp. 8-11
Author(s):  
Jacqueline B. Barnett
Keyword(s):  
Design Process ◽  
Iterative Process ◽  
User Needs ◽  
Work Processes ◽  
Team Members ◽  
Early Design ◽  
Design Changes ◽  
Final Design ◽  
The Individual ◽  
The Cost

The application of ergonomics is important when considering the built environment. In order to create an environment where form follows function, a detailed understanding of the tasks performed by the individuals who will live and work in the facility is required. Early involvement in the project is key to maximizing the benefit of ergonomics. At Sunnybrook and Women's College Health Sciences Centre in Toronto, Canada, this early intervention was embraced during the design process of a behavioural care unit for aggressive patients. The ergonomist was involved in three phases of design; user needs analysis, block schematics and detailed design. The user needs and characteristics were established using a combination of focus groups, interviews, direct observation, task analysis and critique of current working environments. The challenge was to present the information to the design team in a useful manner. The format chosen was a modification of Userfit (Poulson 1996) that outlined the various characteristics of the patient group and the design consequences with “what does this mean for me” statements. During the block schematics phase an iterative design process was used to ensure that the ergonomic principles and the user needs were incorporated into the design. Ergonomic input was used in determining the room sizes and layout and to ensure work processes were considered. Simple mock-ups and anthropometric data assisted in illustrating the need for design changes. Examples that highlight the areas of greatest impact of ergonomic intervention include the patient bathrooms, showers and tub room. Significant changes were made to the design to improve the safety of the work and living space of the end users. One of the greatest challenges was having an appreciation for the individual goals of the team members. Ensuring there was adequate space for equipment and staff often resulted in recommendations for increased space. This in turn would increase the cost of the project. The architect and, later in the project, the engineer had goals of bringing the project in on budget. The final design was very much a team effort and truly die result of an iterative process. The sum of the individual contributions could not match the combined efforts. It was only through the ergonomic contributions in this early design phase that the needs of the staff, patients and families could be so well represented. The success of the iterative process provides the foundation for bringing ergonomics considerations into the early design stages of future projects.

Direct Coupling of a Two-Dimensional Fan Model in a Turbofan Engine Performance Simulation

2016 ◽  
Author(s):  
Ioannis Templalexis ◽  
Alexios Alexiou ◽  
Vassilios Pachidis ◽  
Ioannis Roumeliotis ◽  
Nikolaos Aretakis
Keyword(s):  
Three Dimensional ◽  
Engine Performance ◽  
System Level ◽  
Design Parameters ◽  
High Fidelity ◽  
Two Dimensional ◽  
Performance Simulation ◽  
Cfd Models ◽  
Component Design ◽  
Complex Phenomena

Coupling of high fidelity component calculations with overall engine performance simulations (zooming) can provide more accurate physics and geometry based estimates of component performance. Such a simulation strategy offers the ability to study complex phenomena and their effects on engine performance and enables component design changes to be studied at engine system level. Additionally, component interaction effects can be better captured. Overall, this approach can reduce the need for testing and the engine development time and cost. Different coupling methods and tools have been proposed and developed over the years ranging from integrating the results of the high fidelity code through conventional performance component maps to fully-integrated three-dimensional CFD models. The present paper deals with the direct integration of an in-house two-dimensional (through flow) streamline curvature code (SOCRATES) in a commercial engine performance simulation environment (PROOSIS) with the aim to establish the necessary coupling methodology that will allow future advanced studies to be performed (e.g. engine condition diagnosis, design optimization, mission analysis, distorted flow). A notional two-shaft turbofan model typical for light business jets and trainer aircraft is initially created using components with conventional map-defined performance. Next, a derivative model is produced where the fan component is replaced with one that integrates the high fidelity code. For both cases, an operating line is simulated at sea-level static take-off conditions and their performances are compared. Finally, the versatility of the approach is further demonstrated through a parametric study of various fan design parameters for a better thermodynamic matching with the driving turbine at design point operation.

Exploring System of Systems Resilience vs. Affordability Trade-Space Using a Bio-Inspired Metric

2021 ◽  
pp. 1-13
Author(s):  
Abheek Chatterjee ◽  
Richard Malak ◽  
Astrid Layton
Keyword(s):  
Design Process ◽  
Early Stage ◽  
System Of Systems ◽  
Ecological Research ◽  
Highly Efficient ◽  
Trade Offs ◽  
System Order ◽  
Range Of Values

Abstract The objective of this study is to investigate the value of an ecologically inspired architectural metric called the Degree of System Order in the System of Systems (SoS) architecting process. Two highly desirable SoS attributes are the ability to withstand and recover from disruptions (resilience) and affordability. In practice, more resilient SoS architectures are less affordable and it is essential to balance the trade-offs between the two attributes. Ecological research analyzing long-surviving ecosystems (nature's resilient SoS) using the Degree of System Order metric has found a unique balance of efficient and redundant interactions in their architecture. This balance implies that highly efficient ecosystems tend to be inflexible and vulnerable to perturbations while highly redundant ecosystems fail to utilize resources effectively for survival. Motivated by this unique architectural property of ecosystems, this study investigates the response to disruptions vs. affordability trade-space of a large number of feasible SoS architectures. Results indicate that the most favorable SoS architectures in this trade-space share a specific range of values of Degree of System Order. This suggests that Degree of System Order can be a key metric in engineered SoS development. Evaluating the Degree of System Order does not require detailed simulations and can, therefore, guide the early stage SoS design process towards more optimal SoS architectures.

Yacht Design with Computers: New Methods for New Tools

1983 ◽  
Author(s):  
George S. Hazen ◽  
Steve Killing
Keyword(s):  
Design Process ◽  
Preliminary Design ◽  
Original Design ◽  
New Methods ◽  
Design Office ◽  
Final Design ◽  
Cad Cam

From the perspective of the design office, this paper examines the manner in which computers are streamlining and changing the design process for today's sailing yachts. Starting with preliminary design and progressing through the more detailed aspects of final design, the computer's varying roles in the design process are traced with examples drawn from currently implemented programs. In addition to its customary role as a bookkeeper, the computer's remarkable graphics capabilities are highlighted. The authors offer a glimpse of what programs and hardware tomorrow's yacht designer will use as frequently as his curves and battens. The paper covers such subjects as design follow-up, sailing analysis and feedback into the original design process. Since designers are not the only ones to benefit from the computer revolution, the authors have included sections on computer generated sailing aids for the yachtsman and possible CAD/CAM applications for the boatbuilder.

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