Response Comparisons of a Large Floating Structure by Grillage and Shell FE Models

2008 ◽  
Author(s):  
Kazuhiro Iijima ◽  
Junghyun Kim ◽  
Tetsuya Yao
Keyword(s):  
Stress Responses ◽  
Three Dimensional ◽  
Design Stage ◽  
Design Parameters ◽  
Beam Model ◽  
Floating Structure ◽  
Response Level ◽  
Design Work ◽  
Early Design ◽  
Early Design Stage

At the early design stage of a large floating structure, it is firstly important to know the hydroelastic response characteristics in waves. For this purpose, the structure is modeled by three-dimensional grillage, and hydroelastic analysis is performed in order to estimate the overall behaviour. At this stage, main design parameters are: floater shapes, their arrangement and rigidity distributions. They are optimized by referencing to the hydroelastic responses estimated by the analysis. As the design work develops, more detailed modelling is possible. At the final design stage, the design must be confirmed by checking the response against criteria. The structure is re-modeled by shell FE elements for skin structures and beam elements for stiffeners. It is considered that the more correct estimations are performed by employing the refined model. However, there might be significant differences in the modelling and also in the resultant estimations between the first and final stages even when the subject structure is identical. Then, it is necessary to evaluate the differences between the results estimated by using these two models in order to assure the actual response level estimated by using the beam model at the early design stage. In this paper, three-dimensional grillage and shell FE structural models of a large floating structure are prepared. Hydroelastic analyses are performed on the two models. The results are compared in terms of motion, member force and stress responses.

Design-airworthiness integration method for general aviation aircraft during early development stage

2019 ◽  
Vol 91 (7) ◽  
pp. 1067-1076
Author(s):  
Maxim Tyan ◽  
Jungwon Yoon ◽  
Nhu Van Nguyen ◽  
Jae-Woo Lee ◽  
Sangho Kim
Keyword(s):  
Design Optimization ◽  
Design Stage ◽  
Design Parameters ◽  
Design Framework ◽  
Efficient Design ◽  
Content Type ◽  
Early Design ◽  
Early Design Stage ◽  
Optimization Framework ◽  
Design Requirements

Purpose Major changes of an aircraft configuration are conducted during the early design stage. It is important to include the airworthiness regulations at this stage while there is extensive freedom for designing. The purpose of this paper is to introduce an efficient design framework that integrates airworthiness guidelines and documentation at the early design stage. Design/methodology/approach A new design and optimization process is proposed that logically includes the airworthiness regulations as design parameters and constraints by constructing a certification database. The design framework comprises requirements analysis, preliminary sizing, conceptual design synthesis and loads analysis. A design certification relation table (DCRT) describes the legal regulations in terms of parameters and values suitable for use in design optimization. Findings The developed framework has been validated and demonstrated for the design of a Federal Aviation Regulations (FAR) 23 four-seater small aircraft. The validation results show an acceptable level of accuracy to be applied during the early design stage. The total mass minimization problem has been successfully solved while satisfying all the design requirements and certification constraints specified in the DCRT. Moreover, successful compliance with FAR 23 subpart C is demonstrated. The proposed method is a useful tool for design optimization and compliance verifications during the early stages of aircraft development. Practical implications The new certification database proposed in this research makes it simpler for engineers to access a large amount of legal documentation related to airworthiness regulations and provides a link between the regulation text and actual design parameters and their bounds. Originality/value The proposed design optimization framework integrates the certification database that is built of several types of legal documents such as regulations, advisory circulars and standards. The Engineering Requirements and Guide summarizes all the documents and design requirements into a single document. The DCRT is created as a summary table that indicates the design parameters affected by a given regulation(s), the design stage at which the parameter can be evaluated and its value bounds. The introduction of the certification database into the design optimization framework significantly reduces the engineer’s load related for airworthiness regulations.

scholarly journals APIX: Analysis From Pixellated Inputs in Early Design Using a Pen-Based Interface

2011 ◽  
Author(s):  
Sundar Murugappan ◽  
Vinayak ◽  
Karthik Ramani ◽  
Maria C. Yang
Keyword(s):  
Product Development ◽  
Early Stage ◽  
Three Dimensional ◽  
Geometric Constraints ◽  
Design Stage ◽  
Two Dimensional ◽  
Element Analysis ◽  
Early Design ◽  
Early Design Stage ◽  
Simulation Tools

Product development is seeing a paradigm shift in the form of a simulation-driven approach. Recently, companies and designers have started to realize that simulation has the biggest impact when used as a concept verification tool in early stages of design. Early stage simulation tools like ANSYS™ Design Space and SIMULIA™ DesignSight Structure help to overcome the limitations in traditional product development processes where analyses are carried out by a separate group and not the designers. Most of these commercial tools still require well defined solid models as input and do not support freehand sketches, an integral part of the early design stage of product development. To this extent, we present APIX (acronym for Analysis from Pixellated Inputs), a tool for quick analysis of two dimensional mechanical sketches and parts from their static images using a pen-based interface. The input to the system can be offline (paper) sketches and diagrams, which include scanned legacy drawings and freehand sketches. In addition, images of two-dimensional projections of three dimensional mechanical parts can also be input. We have developed an approach to extract a set of boundary contours to represent a pixellated image using known image processing algorithms. The idea is to convert the input images to online sketches and use existing stroke-based recognition techniques for further processing. The converted sketch can now be edited, segmented, recognized, merged, solved for geometric constraints, beautified and used as input for finite element analysis. Finally, we demonstrate the effectiveness of our approach in the early design process with examples.

Development of New Multi-Dimension Squeezed Penetration Piling Machine

2004 ◽  
Vol 471-472 ◽  
pp. 255-259
Author(s):  
S.Q. Huang ◽  
Y.M. Han ◽  
Yu Dong Wang
Keyword(s):  
Simulation Model ◽  
Product Quality ◽  
Simulation Method ◽  
Design Stage ◽  
Design Parameters ◽  
Simulation Environment ◽  
Early Design ◽  
Early Design Stage ◽  
Development Cycle

The features of a newly developed multi-dimension squeezed penetration piling machine are presented in this paper. The simulation model is built and the squeezing mechanism is tested under simulation environment. With the simulation method key design parameters are predicted at the early design stage; the development cycle can be shortened; and the product quality can be improved.

scholarly journals Novel Methodology for Sizing a Single U-Tube Ground Heat Exchanger Useful at the Early Design Stage

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 651
Author(s):  
Seung-Hyo Baek ◽  
Byung-Hee Lee ◽  
Myoung-Souk Yeo
Keyword(s):  
Heat Exchanger ◽  
Energy Efficient ◽  
Design Method ◽  
Energy System ◽  
Design Stage ◽  
Design Parameters ◽  
Successful Implementation ◽  
Ground Heat Exchanger ◽  
Early Design ◽  
Early Design Stage

Renewable energy system (RES) is an environmentally friendly source of energy. A suitable design of RES is crucial to implement an energy-efficient building such as a zero energy building (ZEB). The significance of appropriate decision-making for the successful implementation of energy-efficient buildings has been increasing. In addition, the identification of the sizing of RES is equally important for architects or HVAC engineers. In this study, a novel sizing method for a single U-tube ground heat exchanger (GHE) is proposed. A transient thermal analysis for a single GHE is performed by considering ground temperature recovery effect as well as other major design parameters. The results are used to design the proposed sizing method and were verified by transient simulations for different design cases. Additionally, it was observed that the coefficient of variation of root mean square error (CV(RMSE)) for all ten design cases was lower than 15% during the heating and cooling seasons. Thus, the proposed design method can be used for sizing a GHE in the early design stage.

Identification of Human Errors During Early Design Stage Functional Failure Analysis

2018 ◽  
Author(s):  
Lukman Irshad ◽  
Salman Ahmed ◽  
Onan Demirel ◽  
Irem Y. Tumer
Keyword(s):  
Failure Analysis ◽  
Human Error ◽  
System Level ◽  
Design Stage ◽  
Human Factors Engineering ◽  
Human Errors ◽  
Functional Failure ◽  
Early Design ◽  
Early Design Stage ◽  
Early Design Stages

Detection of potential failures and human error and their propagation over time at an early design stage will help prevent system failures and adverse accidents. Hence, there is a need for a failure analysis technique that will assess potential functional/component failures, human errors, and how they propagate to affect the system overall. Prior work has introduced FFIP (Functional Failure Identification and Propagation), which considers both human error and mechanical failures and their propagation at a system level at early design stages. However, it fails to consider the specific human actions (expected or unexpected) that contributed towards the human error. In this paper, we propose a method to expand FFIP to include human action/error propagation during failure analysis so a designer can address the human errors using human factors engineering principals at early design stages. To explore the capabilities of the proposed method, it is applied to a hold-up tank example and the results are coupled with Digital Human Modeling to demonstrate how designers can use these tools to make better design decisions before any design commitments are made.

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