Matrix Load Analysis Method for Flexible Aircraft Structures

1981 ◽  
Author(s):  
George W. Martin
Keyword(s):  
Analysis Method ◽  
Flexible Aircraft ◽  
Aircraft Structures ◽  
Load Analysis

Numerical simulation of flexible aircraft structures under ditching loads

2017 ◽  
Vol 8 (3) ◽  
pp. 505-521
Author(s):  
M. H. Siemann ◽  
D. Kohlgrüber ◽  
H. Voggenreiter
Keyword(s):  
Numerical Simulation ◽  
Flexible Aircraft ◽  
Aircraft Structures

scholarly journals A Substructure Synthesis Method with Nonlinear ROM Including Geometric Nonlinearities

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 344
Author(s):  
Chao An ◽  
Yang Meng ◽  
Changchuan Xie ◽  
Chao Yang
Keyword(s):  
Synthesis Method ◽  
Small Deformation ◽  
Nonlinear Fem ◽  
Flexible Wings ◽  
Flexible Aircraft ◽  
Nonlinear Structure ◽  
Geometric Nonlinearities ◽  
Aircraft Structures ◽  
Substructure Synthesis ◽  
Hybrid Interface

Large flexible aircraft are often accompanied by large deformations during flight leading to obvious geometric nonlinearities in response. Geometric nonlinear dynamic response simulations based on full-order models often carry unbearable computing burden. Meanwhile, geometric nonlinearities are caused by large flexible wings in most cases and the deformation of fuselages is small. Analyzing the whole aircraft as a nonlinear structure will greatly increase the analysis complexity and cost. The analysis of complicated aircraft structures can be more efficient and simplified if subcomponents can be divided and treated. This paper aims to develop a hybrid interface substructure synthesis method by expanding the nonlinear reduced-order model (ROM) with the implicit condensation and expansion (ICE) approach, to estimate the dynamic transient response for aircraft structures including geometric nonlinearities. A small number of linear modes are used to construct a nonlinear ROM for substructures with large deformation, and linear substructures with small deformation can also be assembled comprehensively. The method proposed is compatible with finite element method (FEM), allowing for realistic engineering model analysis. Numerical examples with large flexible aircraft models are calculated to validate the accuracy and efficiency of this method contrasted with nonlinear FEM.

Working Load Analysis and Strength Estimation for Bolted Joints During Actual Machine Operation

2014 ◽  
Author(s):  
Soichi Hareyama ◽  
Ken-ichi Manabe ◽  
Takayuki Shimodaira ◽  
Akio Hoshi
Keyword(s):  
Bending Moment ◽  
Bolted Joints ◽  
Lifetime Prediction ◽  
Design Stage ◽  
Bolted Joint ◽  
Analysis Method ◽  
Strength Evaluation ◽  
Test Stage ◽  
Machine Operation ◽  
Load Analysis

Serious problems caused by bolted joint fatigue breakage still occur. This is because working load evaluation and durability strength evaluation have been insufficient in the product design stage, in the test stage of machine lifetime prediction, in the trial production stage, in the prototype machine test stage, and so forth. In this paper, we propose a method for measuring and analyzing the load on bolted joints used in a machine under actual operation. Working load measurement under actual machine operation and the results of its analysis are shown as load frequency diagrams. This is very important information for realizing the concept of simultaneous multiple design. An example of the measurement analysis method of the load (three types of the loads; axial force, bending moment, and the torsional torque) added to the bolted joint shank which comes out at the time of the actual machine operation is shown. The reliability of assessing the strength and durability of bolted joints is considered from the viewpoint of limited-lifetime (finite-lifetime) design using Miner’s rule with cumulative loosening damage models and fatigue limit (infinite-lifetime) design. As an example, we measured the working stress and evaluated the strength of a bolted joint of an actual machine to verify the usefulness of the proposed method. Also, examples of strength evaluation are shown to illustrate finite-lifetime and infinite-lifetime prediction. Moreover, the practical process and presumed example of fatigue life prediction are shown. It is considered as a contribution at the improvement of strength reliability and the load analysis method of the bolted joint of machine develop-ment stage and failure analysis stage. Our findings are also expected to eradicating accidents involving bolted joints in machines.

scholarly journals Limit Load Analysis Method for a Pipe with an Axial Shallow Flaw

2013 ◽  
Vol 79 (799) ◽  
pp. 349-353 ◽  
Author(s):  
Kiminobu HOJO ◽  
Masayuki KAMAYA ◽  
Katsumasa MIYAZAKI
Keyword(s):  
Limit Load ◽  
Analysis Method ◽  
Load Analysis

A Comparison Study of Pressure Vessel Design Using Different Standards

2013 ◽  
Author(s):  
Frode Tjelta Askestrand ◽  
Ove Tobias Gudmestad
Keyword(s):  
Stress Analysis ◽  
Elastic Stress ◽  
Limit Load ◽  
Technical Committee ◽  
Pressure Vessels ◽  
Analysis Method ◽  
Elastic Plastic ◽  
Load Analysis ◽  
American Society ◽  
Division 2

Several codes are currently available for design and analysis of pressure vessels. Two of the main contributors are the American Society of Mechanical Engineers providing the ASME VIII code, Ref /4/ and the Technical Committee for standardization in Brussels providing the European Standard, Ref /2/. Methods written in bold letters will be considered in the discussion presented in this paper. The ASME VIII code, Ref /4/, contains three divisions covering different pressure ranges: Division 1: up to 200 bar (3000 psi) Division 2: in general Division 3: for pressure above 690 bar (10000 psi) In this paper the ASME division 2, Part 5, “design by analysis” will be considered. This part is also referred to in the DNV-OS-F101, Ref /3/, for offshore pressure containing components. Here different analysis methods are described, such as: Elastic Stress Analysis Limit Load Analysis Elastic Plastic Analysis The Elastic Stress Analysis method with stress categorization has been introduced to the industry for many years and has been widely used in design of pressure vessels. However, in the latest issue (2007/2010) of ASME VIII div. 2, this method is not recommended for heavy wall constructions as it might generate non-conservative analysis results. Heavy wall constructions are defined by: (R/t ≤ 4) with dimensions as illustrated in Figure 1. In the case of heavy wall constructions the Limit Load Analysis or the Elastic-plastic method shall be used. In this paper focus will be on the Elastic-plastic method while the Limit Load Analysis will not be considered. Experience from recent projects at IKM Ocean Design indicates that the industry has not been fully aware of the new analysis philosophy mentioned in the 2007 issue of ASME VIII div.2. The Elastic Stress Analysis method is still (2012) being used for heavy wall constructions. The NS-EN 13445-3; 2009, Ref /2/, provides two different methodologies for design by analysis: Direct Route Method based on stress categories. The method based on stress categories is similar to the Elastic Stress Analysis method from ASME VIII div. 2 and it will therefore not be considered in this paper.

scholarly journals Studi Mengenai Analisis Penampang Balok Prategang Parsial pada Beban Kerja. (Hal. 83-95)

2019 ◽  
Vol 5 (2) ◽  
pp. 83
Author(s):  
Dally Margan ◽  
Priyanto Saelan
Keyword(s):  
Prestressed Concrete ◽  
Failure Load ◽  
Analysis Method ◽  
Study Results ◽  
Service Load ◽  
Building Safety ◽  
Load Analysis ◽  
Beam Section ◽  
Prestressed Beam

ABSTRAKPenampang balok prategang parsial dapat dirancang dengan dua metode analisis yaitu metode analisis terhadap beban runtuh dan metode analisis terhadap beban kerja. Perancangan penampang balok prategang parsial pada umumnya dilakukan dengan menggunakan metode analisis terhadap beban runtuh yang telah ditetapkan dalam SNI 03-2847-2002, namun perancangan menggunakan pendekatan beban kerja tidak dicantumkan. Oleh karena itu dilakukan studi analisis untuk mengetahui sejauh mana metode analisis terhadap beban kerja dapat diaplikasikan dalam perancangan penampang balok prategang parsial. Studi kasus ini dilakukan dengan persentase 60, 70, 80, dan 90. Dari hasil studi kasus didapatkan bahwa dengan menggunakan metode analisis terhadap beban kerja dapat dilakukan namun dengan batasan persentase prategang yang beragam yaitu 90, 95, dan 99. Metode analisis terhadap beban kerja dapat dilakukan pada kasus-kasus tertentu dan menggunakan beton dan tendon dengan mutu tinggi untuk faktor keamanan bangunan.Kata kunci: beton prategang parsial, pendekatan beban kerja, persentase prategang, lebar retak ABSTRACTPartial prestressed beam section can be designed with two analysis methods are failure load analysis method and service load analysis method. The design of the partial prestressed beam section generally is using the failure load analysis method which has been specified in SNI 03-2847-2002, but the design with the analytical method of service load is not included. Therefore an analytical study was conducted to determine the extent to which the service load analysis method can be applied for the design of a partial prestressed beam section. This case study was carried out at 60, 70, 80, and 90 prestressed percentages. From the case study results it was found that using the analysis method of service load can be done but with variations of a limited percentage are 90, 95, and 99. The method of analysis of workload can be done in certain cases and using high-quality concrete and tendons for building safety factor.Keywords: partial prestressed concrete, service load analysis method, prestressed percentage, crack width

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