Automatic Generation of Fatigue Analysis Model Reflected the Feature Geometry of the Typical Structural Parts

2009 ◽  
Author(s):  
Seong-Jin Yoo ◽  
◽  
Won-Jun Lee ◽  
Heung-Won Suh ◽  
◽  
...  
Keyword(s):  
Automatic Generation ◽  
Fatigue Analysis ◽  
Analysis Model ◽  
Feature Geometry ◽  
Structural Parts

Ontologies and Fine-Grained Control Over Sharing of Engineering Modeling Knowledge in a Web Based Engineering Environment

2005 ◽  
Author(s):  
Neelima Kanuri ◽  
Ian R. Grosse ◽  
Jack C. Wileden ◽  
Wei-Shan Chiang
Keyword(s):  
Knowledge Sharing ◽  
Knowledge Base ◽  
Automatic Generation ◽  
Base System ◽  
Engineering Analysis ◽  
Analysis Model ◽  
Web Based ◽  
Technical Report ◽  
Engineering Modeling ◽  
Base Application

Within the knowledge modeling community the use of ontologies in the construction of knowledge intensive systems is now widespread. Ontologies are used to facilitate knowledge sharing, reuse, agent interoperability and knowledge acquisition. We have developed an ontology for representing and sharing engineering analysis modeling (EAM) knowledge in a web-based environment and implemented these ontologies into a computational knowledge base system, called ON-TEAM, using Prote´ge´1. In this paper we present new object-oriented methods that operate on the EAM knowledge base to perform specific tasks. One such method is the creation of a flat technical report that describes the properties or class relationships of an engineering modeling analysis class and/or the modeling knowledge involved in the development of a specific engineering analysis model. This method is a JAVA application that accesses the EAM knowledge base application using the Prote´ge´ application programming interface. It presents the user a graphical user interface for selecting the EAM class or specific analysis model instance and then exports the appropriate knowledge to a text file to form the basis of a technical report. Secondly, a method controlling knowledge access and sharing is under development which allocates permissions to portions of the knowledge base according to accessibility permissions. This method controls as efficiently as possible fine grain knowledge sharing. Both the methods acting together enable automatic generation of recipient-specific technical reports based on the recipient’s security permissions, customized knowledge viewing, and customized knowledge exporting through various knowledge exchange formats such as XML Walsh [1], RDF Klyne [2], etc. Finally, implementation of these methods and our EAM knowledge base application as components within commercial web-based distributed software architecture is presented.

Automatic Differentiation in Automatic Generation of the Linearized Equations of Motion

2021 ◽  
Author(s):  
Bruce Minaker ◽  
Francisco González
Keyword(s):  
Multibody Systems ◽  
Automatic Differentiation ◽  
Equations Of Motion ◽  
Computational Cost ◽  
Order Reduction ◽  
Automatic Generation ◽  
Analysis Model ◽  
Direct Evaluation ◽  
Base Function ◽  
Linearized Equations

Abstract In the ongoing search for mathematically efficient methods of predicting the motion of vehicle and other multibody systems, and presenting the associated results, one of the avenues of continued interest is the linearization of the equations of motion. While linearization can potentially result in reduced fidelity in the model, the benefits in computational speed often make it the pragmatic choice. Linearization techniques are also useful in modal and stability analysis, model order reduction, and state and input estimation. This paper explores the application of automatic differentiation to the generation of the linearized equations of motion. Automatic differentiation allows one to numerically evaluate the derivative of any function, with no prior knowledge of the differential relationship to other functions. It exploits the fact that every computer program must evaluate every function using only elementary arithmetic operations. Using automatic differentiation, derivatives of arbitrary order can be computed, accurately to working precision, with minimal additional computational cost over the evaluation of the base function. There are several freely available software libraries that implement automatic differentiation in modern computing languages. In the paper, several example multibody systems are analyzed, and the computation times of the stiffness matrix are compared using direct evaluation and automatic differentiation. The results show that automatic differentiation can be surprisingly competitive in terms of computational efficiency.

Virtual Prototype Design and Test-Simplifying the CAD/Analysis Interface

2013 ◽  
Vol 284-287 ◽  
pp. 3473-3476
Author(s):  
Qiong Li ◽  
Carol A. Rubin
Keyword(s):  
Finite Element ◽  
Structural Integrity ◽  
Medial Axis ◽  
Three Dimensional ◽  
Virtual Design ◽  
Element Analysis ◽  
Feature Geometry ◽  
Cad Models ◽  
Structural Parts ◽  
Treat All

The design of mechanical structural parts is now predominantly a digital process. As an important element of the virtual design cycle, these parts must be tested for their structural integrity using finite element analysis (FEA) software. However, the interface between CAD and FEA is imperfect. The process of preparing CAD models for FEA consumes a great deal of the stress analyst’s time. Existing “automatic” CAD to FEA translators tend to treat all part features as “solid”; this leads to longer computation times and less accurate results for features that can be better characterized as “thin” or “long.” In addition, many features of CAD parts (e.g. fillets and chamfers) are important for their size and shape in the manufactured product, but have relatively little impact on the strength of the part and needlessly complicate the stress analysis—these features are usually removed by the analyst prior to FEA; they may need to be evaluated with additional analyses to test if it is safe to remove them. The Automatic CAD-FEA Interface Project (ACFI), is developing algorithms to make the translation from CAD to FEA seamless and automatic; these algorithms are based on mathematical theory and the principles of theoretical mechanics. This paper presents the latest ACFI advances for (i) automatically evaluating and reworking three dimensional CAD part geometries to prepare them for finite element meshing, (ii) exporting the revised geometries to a preprocessor, and (iii) identifying element type to be associated with each feature geometry. The algorithms used in this work approximate the medial axis transform (MAT) of the CAD part, a “power shape” that represents the three-dimensional solid part. This part can then be evaluated for its geometric properties. This approach has been shown to be a robust method for shape interrogation of three dimensional geometries.

scholarly journals Hardware/Software Co-design Flow Using Automatic Generation of Embedded System Framework Based on Interacting FSM Model

2020 ◽  
Vol 12 (4) ◽  
pp. 859-877
Author(s):  
Arif Sasongko ◽  
Keyword(s):  
Embedded System ◽  
Automatic Generation ◽  
Design Flow ◽  
Analysis Model ◽  
System Framework ◽  
Code Generator ◽  
Finite State ◽  
The Embedded System ◽  
Automatic Code ◽  
High Level

Today’s embedded System is complex. An embedded system design project may involve of various engineering field. A rapidly-available and well-defined framework code brings advantages to the team consists of many engineers from various domains. This framework must be easy to use for communication purpose and analysis (model). This paper proposes a design flow based on a model which is high level but precise enough to use in automatic generation of the embedded system framework code. The model is flexible for rapid modification. The event driven paradigm and the FSM are used in the model. The design flow uses the model to generate framework code based on an existing platform. The work presented in this paper produces tool for the generation which is called EBGES. The proposed model describes the system as set of finite state machines (FSM) and events. This model serves for two purposes: (1) to be discussed by the developers/various engineers before deciding the platform and the architecture of the system, (2) to be used for generating the framework code. An automatic code generator is developed to produce a framework code from the model. The framework consists of (1) the FSM for every block, (2) communications between the FSMs, (3) function prototypes (for software) for function used by FSM, (4) interface of hardware module used by the FSMs, (5) instantiation of the platform. The generator software takes the model in form of annotated diagrams which are created schematically using a GUI environment. The diagrams follow UML standard. The outputs are VHDL code for hardware and C code for the software part. Example of calculator application is developed to test the tool and the flow. The generated framework code in the calculator experiment accelerated the development. Up to 51% of the code is generated automatically and 49 % of the code is written manually. The result of the experiment shows significantly improvement on design productivity which is the comes from: (1) abstraction of the behavior of subsystems/modules (HW or SW) by hiding unnecessary detail and (2) automatic generation of the framework code.

Wellhead Fatigue Analysis Method: The Effect of Variation of Lower Boundary Conditions in Global Riser Load Analysis

2012 ◽  
Author(s):  
Lorents Reinås ◽  
Massimiliano Russo ◽  
Guttorm Grytøyr
Keyword(s):  
Boundary Condition ◽  
Boundary Conditions ◽  
Lower Boundary ◽  
Fatigue Analysis ◽  
Analysis Model ◽  
Lower Boundary Condition ◽  
Analysis Methodology ◽  
Well Integrity ◽  
Context Modelling ◽  
Load Analysis

Subsea wellhead mechanical fatigue can potentially result in a gross structural failure of barrier elements in the upper part of the well, potentially resulting in loss of well control. Several major E&P operators have acknowledged the importance of wellhead fatigue and are participating in the JIP “Structural Well Integrity”. It is within the scope of this JIP to develop a recommended practice for wellhead fatigue analysis methodology. The analysis methodology currently being investigated by the JIP is a decoupled approach, with modifications of the lower boundary to account for the stiffness of the conductor, soil and template interface. A detailed local wellhead model is used to generate the lower boundary condition for a decoupled global riser load analysis model. This lower boundary condition definition is intended to capture the overall non-linear stiffness of a site specific well in order to achieve best possible global riser loads estimate. In this article the effect of varying the lower boundary conditions on a global load estimate is studied. Global load estimates are generated from a typical North Sea case and various lower boundary conditions are introduced as the only change to the global riser model. A fixed lower boundary condition is used as a reference and load estimates generated from riser models with various lower boundary conditions are compared. The different lower boundary conditions selected for comparison in this study has been derived from the following cases: 1. Fixed at WH 2. As per ISO 13624-2 3. As per JIP “Structural Well Integrity” -Current 4. As per JIP “Structural Well Integrity” -Modified Comparing the analysis results gives indications that the lower boundary condition modelling approach affect global riser load estimate. The fixed lower end boundary conditions did not yielded the most conservative load history in a fatigue context. Modelling well specific flexibility at the riser lower end increased the total number of wellhead fatigue load cycles. This finding support the current approach suggested by the works of the JIP “Structural Well Integrity”. Ensuring that riser load results are still conservative places a higher importance on precise local modelling of the well system.

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