Delamination Under Fatigue Loads in Composite Laminates: A Review on the Observed Phenomenology and Computational Methods

2014 ◽  
Vol 66 (6) ◽  
Author(s):  
Brian L. V. Bak ◽  
Carlos Sarrado ◽  
Albert Turon ◽  
Josep Costa
Keyword(s):  
Design Process ◽  
Computational Methods ◽  
Structural Design ◽  
Composite Laminates ◽  
Composite Structures ◽  
State Of The Art ◽  
Computational Simulation ◽  
Simulation Methods ◽  
Short Term ◽  
Current State

Advanced design methodologies enable lighter and more reliable composite structures or components. However, efforts to include fatigue delamination in the simulation of composites have not yet been consolidated. Besides that, there is a lack of a proper categorization of the published methods in terms of their predictive capabilities and the principles they are based on. This paper reviews the available experimental observations, the phenomenological models, and the computational simulation methods for the three phases of delamination (initiation, onset, and propagation). It compiles a synthesis of the current state-of-the-art while identifying the unsolved problems and the areas where research is missing. It is concluded that there is a lack of knowledge, or there are unsolved problems, in all categories in the field, but particularly in the category of computational methods, which in turn prevents its inclusion in the structural design process. Suggested areas where short-term and midterm research should be focused to overcome the current situation are identified.

Advancement in the Application of Finite Element Analysis to the Optimization of Composite Yacht Structures

2011 ◽  
Author(s):  
David Fornaro
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Structures ◽  
State Of The Art ◽  
Load Case ◽  
Post Processing ◽  
Principal Stresses ◽  
Element Analysis ◽  
Current State ◽  
Case Development

Finite Element Analysis (FEA) is mature technology that has been in use for several decades as a tool to optimize structures for a wide variety of applications. Its application to composite structures is not new, however the technology for modeling and analyzing the behavior of composite structures continues to evolve on several fronts. This paper provides a review of the current state-of-the-art with regard to composites FEA, with a particular emphasis on applications to yacht structures. Topics covered are divided into three categories: Pre-processing; Postprocessing; and Non-linear Solutions. Pre-processing topics include meshing, ply properties, laminate definitions, element orientations, global ply tracking and load case development. Post-processing topics include principal stresses, failure indices and strength ratios. Nonlinear solution topics include progressive ply failure. Examples are included to highlight the application of advanced finite element analysis methodologies to the optimization of composite yacht structures.

scholarly journals Current State of Development of Ship Structural Design and Optimization Methods

2020 ◽  
Vol 3 (3) ◽  
pp. 171-187
Author(s):  
Marin Palaversa ◽  
Pero Prebeg ◽  
Jerolin Andrić
Keyword(s):  
Sensitivity Analysis ◽  
Support System ◽  
Structural Design ◽  
State Of The Art ◽  
Optimization Methods ◽  
Offshore Structures ◽  
Engineering Practice ◽  
Design And Optimization ◽  
Current State ◽  
Design Support System

This paper presents state-of-the-art methodologies and methods used in the rationally-based structural design of ships and offshore structures, namely design support system, structural optimization, surrogate modelling and sensitivity analysis. It demonstrates their application in structural design of a platform support vessel. It ends with a list of benefits that a structural designer may expect when the presented methods/methodologies are used. It also shows the obstacles to their full implementation in the engineering practice.

scholarly journals Computational Linguistics in Support of Linguistic Theory

2010 ◽  
Vol 3 ◽  
Author(s):  
Emily M. Bender ◽  
D. Terence Langendoen
Keyword(s):  
Computational Methods ◽  
Computational Linguistics ◽  
State Of The Art ◽  
Theory Development ◽  
Linguistic Theory ◽  
Linguistic Data ◽  
Current State

In this paper, we overview the ways in which computational methods can serve the goals of analysis and theory development in linguistics, and encourage the reader to become involved in the emerging cyberinfrastructure for linguistics. We survey examples from diverse subfields of how computational methods are already being used, describe the current state of the art in cyberinfrastructure for linguistics, sketch a pie-in-the-sky view of where the field could go, and outline steps that linguists can take now to bring about better access to and use of linguistic data through cyberinfrastructure.

System Reliability and Redundancy of Marine Structures: A Review of the State of the Art

1990 ◽  
Vol 34 (01) ◽  
pp. 48-59 ◽  
Author(s):  
Efstratios Nikolaidis ◽  
Rakesh K. Kapania
Keyword(s):  
System Reliability ◽  
Structural Design ◽  
Composite Structures ◽  
State Of The Art ◽  
Laminated Composite ◽  
Structural Redundancy ◽  
Marine Structures ◽  
Laminated Composite Structures ◽  
Critical Problems ◽  
Reserve Strength

This paper is a survey of state-of-the-art knowledge in system reliability and redundancy. Measures of structural redundancy and reserve strength are presented and their advantages and limitations reviewed. Methods for calculating system reliability are critically reviewed. Emphasis is given to the underlying assumptions and the resulting limitations. Reliability of laminated composite structures is also considered. The potential of system reliability in structural design is emphasized. Recent studies on this subject are reviewed. The most critical problems in each of the above topics are identified and strategies for solving them are proposed.

scholarly journals SWIM: A Simple Word Interaction Model for Implicit Discourse Relation Recognition

2017 ◽  
Author(s):  
Wenqiang Lei ◽  
Xuancong Wang ◽  
Meichun Liu ◽  
Ilija Ilievski ◽  
Xiangnan He ◽  
...  
Keyword(s):  
Short Term Memory ◽  
State Of The Art ◽  
Interaction Model ◽  
Weighted Averaging ◽  
Short Term ◽  
Current State ◽  
Proposed Model ◽  
Order Of Magnitude ◽  
Long Short Term Memory ◽  
Semantic Interaction

Capturing the semantic interaction of pairs of words across arguments and proper argument representation are both crucial issues in implicit discourse relation recognition. The current state-of-the-art represents arguments as distributional vectors that are computed via bi-directional Long Short-Term Memory networks (BiLSTMs), known to have significant model complexity.In contrast, we demonstrate that word-weighted averaging can encode argument representation which can incorporate word pair information efficiently. By saving an order of magnitude in parameters, our proposed model achieves equivalent performance, but trains seven times faster.

scholarly journals ADAPTABLE DESIGN FOR DESIGN REUSE

2011 ◽  
Author(s):  
D. Fletcher ◽  
P. Gu
Keyword(s):  
Design Process ◽  
State Of The Art ◽  
Future Research ◽  
Design Reuse ◽  
Creative Design ◽  
Design Information ◽  
Adaptable Design ◽  
Research Areas ◽  
Current State ◽  
Previous Design

Due to the complexity, associated cost, and general uncertainty of performing the creative design process, significant value exists in reusing the design information developed in previous design efforts. This paper outlines the current state of the art in design reuse in various fields as well as identifying both the current and future research areas. In addition, this paper describes the link between adaptable design and design reuse. Finally, as the first step in our research, this paper describes the direction that the research will take: an analysis of the use of adaptable design to enhance the design reuse process.

Multicriteria Optimization in Structural Design: State of the Art

1993 ◽  
Author(s):  
Juhani Koski
Keyword(s):  
Design Process ◽  
Pareto Optimality ◽  
Structural Design ◽  
State Of The Art ◽  
Research Work ◽  
General Description ◽  
Open Questions ◽  
Basic Concepts ◽  
Made In

Abstract The purpose of this article is to give a general description of the research work made in the field of multicriteria structural optimization. More than eighty publications have been considered in this study where completed works rather than open questions in the field are particularly emphasized. The basic concepts, especially Pareto optimality, and the motivation of the multicriteria approach are briefly discussed. The classification of the multicriteria structural design process is proposed and it is used in describing the published applications.

scholarly journals Loads analysis and structural optimization of a high aspect ratio, composite wing aircraft

2021 ◽  
Author(s):  
Kautuk Sinha ◽  
Thomas Klimmek ◽  
Matthias Schulze ◽  
Vega Handojo
Keyword(s):  
Aspect Ratio ◽  
Structural Optimization ◽  
Design Process ◽  
High Aspect Ratio ◽  
Structural Design ◽  
Composite Structures ◽  
Selection Process ◽  
Weight Ratio ◽  
Bending Moment ◽  
Composite Wing

AbstractComposite structures have shown a prominent impact in the aircraft structural design. With an increasing shift towards incorporating more composite materials in the primary aircraft structure it is imperative to have corresponding design tools to simplify the design process. In the present work, a simplified implementation for composite optimization has been developed within the DLR-AE (German Aerospace Centre, Institute of Aeroelasticity) automated aeroelastic structural design framework cpacs-MONA. This paper presents the results of structural optimization of a high aspect ratio composite wing aircraft model developed in the DLR project ATLAs. The generation of almost all involved simulation models for this study is done using the in-house DLR tool ModGen. An aeroelastic trim analysis is conducted for various manoeuvre and gust conditions. A load selection process is used to determine the most relevant sizing load cases. A comparison is made between the optimization results of a composite wing and an aluminium wing to demonstrate the more favourable strength to weight ratio of the composite wing. A manoeuvre load alleviation procedure has been introduced in the load calculation process. The results show further weight savings in the design process when load alleviation is utilized due to reduction in the span wise bending moment.

Modeling and Simulation Methods for Design of Engineering Systems

2000 ◽  
Vol 1 (1) ◽  
pp. 84-91 ◽  
Author(s):  
Rajarishi Sinha ◽  
Christiaan J. J. Paredis ◽  
Vei-Chung Liang ◽  
Pradeep K. Khosla
Keyword(s):  
Modeling And Simulation ◽  
Design Process ◽  
State Of The Art ◽  
Simulation Software ◽  
Modeling Languages ◽  
Simulation Methods ◽  
Design Tools ◽  
Engineering Systems ◽  
Simulation Based Design ◽  
Simulation Based

This article presents an overview of the state-of-the art in modeling and simulation, and studies to which extent current simulation technologies can effectively support the design process. For simulation-based design, modeling languages and simulation environments must take into account the special characteristics of the design process. For instance, languages should allow models to be easily updated and extended to accommodate the various analyses performed throughout the design process. Furthermore, the simulation software should be well integrated with the design tools so that designers and analysts with expertise in different domains can effectively collaborate on the design of complex artifacts. This review focuses in particular on modeling for design of multi-disciplinary engineering systems that combine continuous time and discrete time phenomena.

scholarly journals Prediction and clarification of structures of (bio)molecules on surfaces

2016 ◽  
Vol 71 (5) ◽  
pp. 351-374 ◽  
Author(s):  
J. Christian Schön ◽  
Christina Oligschleger ◽  
Juan Cortes
Keyword(s):  
Computational Methods ◽  
State Of The Art ◽  
The Self ◽  
Self Organization ◽  
Biotechnological Applications ◽  
Current State ◽  
Equal Importance ◽  
Structure Patterns

AbstractThe design of future materials for biotechnological applications via deposition of molecules on surfaces will require not only exquisite control of the deposition procedure, but of equal importance will be our ability to predict the shapes and stability of individual molecules on various surfaces. Furthermore, one will need to be able to predict the structure patterns generated during the self-organization of whole layers of (bio)molecules on the surface. In this review, we present an overview over the current state of the art regarding the prediction and clarification of structures of biomolecules on surfaces using theoretical and computational methods.

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