scholarly journals Analisis Numerik Part Bulkhead Pada Sub System Wing To Fuselage Joinner Assembly Pesawat Aerobatik Menggunakan Metode Elemen Hingga

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Enggar Kristian ◽  
Agus Suprianto ◽  
Nurhadi Pramana ◽  
Sahril Afandi ◽  
Endah Yuniarti
Keyword(s):  
Incidence Angle ◽  
Failure Criteria ◽  
Topological Optimization ◽  
Structural Failure ◽  
Topological Approach ◽  
Approach Method ◽  
Margin Of Safety ◽  
Problem Solving Process ◽  
Aluminum Alloy 7075 ◽  
Geometric Variation

Analisis rancangan bulkhead dilakukan untuk memperoleh geometri terbaik untuk mencari berat yang efisien dengan mengubah geometri bentuk pada bulkhead yang merupakan sub system wing to fuselage untuk pesawat berkategori aerobatik dan berat yang optimal yang memenuhi persyaratan regulasi FAR 23 dan mengetahui respon distribusi tegangan, bending yang dihasilkan  dan kriteria kegagalan struktur berdasarkan variasi geometri bentuk bulkhead. Pada penelitian ini untuk analisis statik bulkhead untuk pesawat berkategori aerobatik menggunakan material Aluminium Alloy 7075-T6 dan menggunakan metode pendekatan Schrenk untuk menghitung beban eksternal distrbusi gaya angkat pada sayap. Selain itu dilakukan proses optimisasi berat bulkhead berdasarkan metode pendekatan topologi yaitu perubahan geometri bentuk pada bulkhead untuk mereduksi berat, sudut insiden spar yang berbeda dan menghitung magin of safety. Proses penyelesaian masalah menggunakan perangkat lunak metode elemen hingga (Abaqus CAE). Optimisasi topologi pada part bulkhead sudut insidet 0° dan 4° menghasilkan volume yang berkurang pada benda sehingga mereduksi berat, tetapi nilai dari margin of safety MS = 0. The bulkhead design analysis was carried out to obtain the best geometry to find an efficient weight by changing the shape geometry of the bulkhead which is a sub-system of the wing to the fuselage for an aircraft categorized as aerobatics and an optimal weight that meets the requirements of FAR 23 regulations and sees the stress distribution response, the resulting bending and structural failure criteria based on the geometric variation of bulkhead shapes. In this study, to analyze the bulkhead static for an aerobatic category aircraft using Aluminum Alloy 7075-T6 material and using the Schrenk Approximation method to calculate the external distribution load of lift force on the wing. In addition, the optimization of bulkhead weight based on the topological approach method is to change the shape geometry of the bulkhead to reduce weight, in different spar incidents and calculate margin of safety. The problem solving process uses finite element method software (Abaqus CAE). Topological optimization of the bulkhead part with an incidence angle of 0 ° and 4 ° results in a reduced volume of the object so that it reduces weight, but the value of the margin of safety MS = 0.  

Symbolic Algebra and Theorem Proving for Failure Criteria Reduction

2011 ◽  
Author(s):  
John G. Michopoulos ◽  
Athanasios Iliopoulos
Keyword(s):  
Theorem Proving ◽  
Strain Energy ◽  
Failure Criteria ◽  
Orthotropic Materials ◽  
Structural Failure ◽  
Symbolic Algebra ◽  
Symbolic Computing ◽  
Strain Energy Density Function ◽  
Bner Basis ◽  
Strain Space

The present paper reports on recent efforts of utilizing symbolic computing for identifying failure criteria cross reducibility from the perspective of theorem proving. Utilizing equational theorem proving algorithms and Gro¨bner Basis polynomial theorem provers implemented in Mathematica we have proven a number of interesting theorems related to the area of structural failure criteria for anisotropic and particularly orthotropic materials. The main contribution of this work is the demonstration of the tremendous utility of symbolic algebra for engineering applications as well as the demonstration of the idea that all failure criteria presented in the literature up to know can be proven under certain conditions to be special forms of general criteria relating to the strain energy density function associated with material continua. Two specific examples are presented and discussed along with a theorem proving the existence of a dual form of all stress space based criteria to equivalent one expressed in strain space.

scholarly journals Computational analysis of thermal and structural failure criteria of a multi-storey steel frame exposed to fire

2019 ◽  
Vol 180 ◽  
pp. 524-543 ◽  
Author(s):  
Egle Rackauskaite ◽  
Panagiotis Kotsovinos ◽  
Ann Jeffers ◽  
Guillermo Rein
Keyword(s):  
Computational Analysis ◽  
Failure Criteria ◽  
Steel Frame ◽  
Structural Failure

A particular criterion for progressive failure analysis of carbon/phenolic tape-wounded conic shells

2021 ◽  
pp. 105678952199591
Author(s):  
SA Hosseini Kordkheili ◽  
M Karimian ◽  
HR Jafari
Keyword(s):  
Failure Analysis ◽  
Composite Structures ◽  
Progressive Failure ◽  
Failure Criteria ◽  
Solution Algorithm ◽  
Shell Structures ◽  
Finite Element Software ◽  
Progressive Failure Analysis ◽  
Conic Shell ◽  
Margin Of Safety

Conic shell structures are widely used in aerospace industries. In the literature various models have been proposed to failure analysis of composite materials. Clearly, each model has a favorable range of applications. In this paper tensile, compressive, shear and thermal expansion properties of tape-wounded Carbon/Phenolic composites are firstly measured at various temperatures in range 23–200°C. The captured properties are then taken into account to progressive failure analysis of a conic Carbon/Phenolic structure under internal pressure and thermal loadings. For this end, a particular failure criterion is proposed to predict failure in the composite structures with a reasonable margin of safety. The enhanced model is then implemented into the commercial finite element software of ABAQUS via a developed user material (UMAT) subroutine utilizing a suitable solution algorithm. Advantages of the model are assessed and comparisons with other failure criteria as well as experiment are presented.

Assessment of Current High-Temperature Design Methodology Based on Structural Failure Tests

1987 ◽  
Vol 109 (2) ◽  
pp. 160-168 ◽  
Author(s):  
J. M. Corum ◽  
W. K. Sartory
Keyword(s):  
High Temperature ◽  
Design Methodology ◽  
Service Failure ◽  
Failure Criteria ◽  
The United States ◽  
Department Of Energy ◽  
Structural Failure ◽  
Inelastic Analysis ◽  
Inelastic Responses ◽  
Asme Code

A mature design methodology, consisting of inelastic analysis methods provided in U.S. Department of Energy guidelines and failure criteria contained in ASME Code Case N-47, exists in the United States for high-temperature reactor components. The objective of this paper is to assess the adequacy of that overall methodology by comparing predicted inelastic deformations and lifetimes with observed results from structural failure tests and from an actual service failure. Comparisons are presented for three structural cases: 1) nozzle-to-spherical shell specimens, emphasizing stresses at structural discontinuities; 2) welded structures, emphasizing metallurgical discontinuities; and 3) thermally loaded cylinders and pipes, emphasizing thermal discontinuities. The comparisons between predicted and measured inelastic responses are generally reasonable; quantities are sometimes overpredicted somewhat and sometimes underpredicted. However, even seemingly small discrepancies in predicted stresses and strains can have a significant effect on life, which is thus not always as closely predicted. For a few cases, the lifetimes are substantially overpredicted, which raises questions regarding the methodology and/or the adequacy of the current design margins.

scholarly journals Designing Incidence-Angle-Targeted Anti-Cavitation Foil Profiles Using a Combination Optimization Strategy

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3099 ◽  
Author(s):  
Di Zhu ◽  
Ruofu Xiao ◽  
Ran Tao ◽  
Fujun Wang
Keyword(s):  
Optimization Design ◽  
Design Method ◽  
Incidence Angle ◽  
Leading Edge ◽  
Hill Climbing ◽  
Optimization Strategy ◽  
Hydraulic Machinery ◽  
Global Dynamic ◽  
Cavitation Performance ◽  
Geometric Variation

In hydraulic machinery, the surface of the blade can get damaged by the cavitation of the leading-edge. In order to improve the cavitation performance, the anti-cavitation optimization design of blade leading-edge is conducted. A heuristic-parallel locally-terminated improved hill-climbing algorithm, which is named as the global dynamic-criterion (GDC) algorithm was proposed in this study. The leading-edge shape of NACA 0009-mod foil profile was optimized by combining the GDC algorithm, CFD prediction, Diffusion-angle Integral (DI) design method and orthogonal test. Three different optimal foil geometries were obtained for specific incidence angles that 0, 3, and 6 degrees. According to the flow field analyses, it was found that the geometric variation of the optimized foil fits the incoming flow better at the respective optimal incidence angles due to a slighter leading-edge flow separation. The pressure drops become gentler so that the cavitation performance get improved. Results show that the GDC algorithm quickly and successfully fits the target condition by parallel running with the ability against falling into local-best tarps. The −Cpmin of the optimal foils was improved especially by +11.4% and +14.5% at 3 and 6 degrees comparing with the original foil. This study provided a reference for the anti-cavitation design of hydraulic machinery blades.

Electron Channeling Patterns

1977 ◽  
Vol 35 ◽  
pp. 12-13
Author(s):  
David C. Joy
Keyword(s):  
Electron Diffraction ◽  
Incidence Angle ◽  
Photographic Plate ◽  
Diffraction Effect ◽  
Angle Of Incidence ◽  
Bulk Single Crystal ◽  
Time Resolved ◽  
Electron Channeling ◽  
Spatially Resolved ◽  
Large Bulk

Electron channeling patterns (ECP) were first found by Coates (1967) while observing a large bulk, single crystal of silicon in a scanning electron microscope. The geometric pattern visible was shown to be produced as a result of the changes in the angle of incidence, between the beam and the specimen surface normal, which occur when the sample is examined at low magnification (Booker, Shaw, Whelan and Hirsch 1967).A conventional electron diffraction pattern consists of an angularly resolved intensity distribution in space which may be directly viewed on a fluorescent screen or recorded on a photographic plate. An ECP, on the other hand, is produced as the result of changes in the signal collected by a suitable electron detector as the incidence angle is varied. If an integrating detector is used, or if the beam traverses the surface at a fixed angle, then no channeling contrast will be observed. The ECP is thus a time resolved electron diffraction effect. It can therefore be related to spatially resolved diffraction phenomena by an application of the concepts of reciprocity (Cowley 1969).

Atomic force microscopy (AFM) of the topography of silicon surfaces exposed to ion beams

1992 ◽  
Vol 50 (2) ◽  
pp. 1132-1133
Author(s):  
Mark Denker ◽  
Jennifer Wall ◽  
Mark Ray ◽  
Richard Linton
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Incidence Angle ◽  
Ion Beam ◽  
Depth Profiling ◽  
Depth Resolution ◽  
Ion Beams ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Trace Impurities ◽  
Energy Dose

Reactive ion beams such as O2+ and Cs+ are used in Secondary Ion Mass Spectrometry (SIMS) to analyze solids for trace impurities. Primary beam properties such as energy, dose, and incidence angle can be systematically varied to optimize depth resolution versus sensitivity tradeoffs for a given SIMS depth profiling application. However, it is generally observed that the sputtering process causes surface roughening, typically represented by nanometer-sized features such as cones, pits, pyramids, and ripples. A roughened surface will degrade the depth resolution of the SIMS data. The purpose of this study is to examine the relationship of the roughness of the surface to the primary ion beam energy, dose, and incidence angle. AFM offers the ability to quantitatively probe this surface roughness. For the initial investigations, the sample chosen was <100> silicon, and the ion beam was O2+.Work to date by other researchers typically employed Scanning Tunneling Microscopy (STM) to probe the surface topography.

Principle and practice of high-resolution imaging with a field-emission TEM

1992 ◽  
Vol 50 (1) ◽  
pp. 138-139
Author(s):  
Max T. Otten ◽  
Wim M.J. Coene
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Incidence Angle ◽  
Temporal Coherence ◽  
Energy Spread ◽  
High Resolution Imaging ◽  
Major Improvement ◽  
High Resolution Images ◽  
Resolution Imaging

High-resolution imaging with a LaB6 instrument is limited by the spatial and temporal coherence, with little contrast remaining beyond the point resolution. A Field Emission Gun (FEG) reduces the incidence angle by a factor 5 to 10 and the energy spread by 2 to 3. Since the incidence angle is the dominant limitation for LaB6 the FEG provides a major improvement in contrast transfer, reducing the information limit to roughly one half of the point resolution. The strong improvement, predicted from high-resolution theory, can be seen readily in diffractograms (Fig. 1) and high-resolution images (Fig. 2). Even if the information in the image is limited deliberately to the point resolution by using an objective aperture, the improved contrast transfer close to the point resolution (Fig. 1) is already worthwhile.

Moving to Solution

2013 ◽  
Vol 60 (6) ◽  
pp. 403-409 ◽  
Author(s):  
K. Werner ◽  
M. Raab
Keyword(s):  
Problem Solving ◽  
Embodied Cognition ◽  
Cognitive Functions ◽  
Problem Space ◽  
Arm Swing ◽  
String Problem ◽  
Problem Solving Process ◽  
Problem Solving Task ◽  
Bodily Movements

Embodied cognition theories suggest a link between bodily movements and cognitive functions. Given such a link, it is assumed that movement influences the two main stages of problem solving: creating a problem space and creating solutions. This study explores how specific the link between bodily movements and the problem-solving process is. Seventy-two participants were tested with variations of the two-string problem (Experiment 1) and the water-jar problem (Experiment 2), allowing for two possible solutions. In Experiment 1 participants were primed with arm-swing movements (swing group) and step movements on a chair (step group). In Experiment 2 participants sat in front of three jars with glass marbles and had to sort these marbles from the outer jars to the middle one (plus group) or vice versa (minus group). Results showed more swing-like solutions in the swing group and more step-like solutions in the step group, and more addition solutions in the plus group and more subtraction solutions in the minus group. This specificity of the connection between movement and problem-solving task will allow further experiments to investigate how bodily movements influence the stages of problem solving.

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