A GUI for a Software that Analyses a Composite Bolted Joint

FastComp is a computational tool for the determination of the forces that a composite bolted joint subjected to multiaxial loads supports until failure occurs. The main intention of the present work was the development of a graphical user interface (GUI) for the referred tool that allows its parameterization and the visualization of its output results. Using VTK The Visualization Toolkit, a computational library for graphical structures, visualization and image processing; C#, an object-oriented programming language; and the design principles of an adequate human-computer interaction, a graphical interface was developed as an efficient and effective means of interaction with FastComp. This interface was then evaluated by some users

Development of a software for the design of adhesive joints

Tese de mestrado integrado. Engenharia Mecânica. Faculdade de Engenharia. Universidade do Porto. 200

Manual Revision Process for Project-Based Laboratory Instruction

A four-step laboratory manual revision process was developed in this study based upon a technical writing process for supporting project-based laboratory classes. The audience and the objectives of this type of laboratory manuals are quite different from those of traditional, descriptive laboratory classes. The project-based laboratory manual has to serve as both an operational handbook and a theoretical textbook. The proposed four-step manual revision process was implemented in the fall 2016 semester in a 3-credit, senior elective class which was built upon a commercially-rated finite element analysis software package. Student surveys and evaluations showed that the revision process greatly increased student engagement in the class and, as a result, increased student learning effectiveness

A comparative study of ultimate load and stiffness of metal-to-composite joints

V současnosti jedna z metod spojování zejména tlustých a vysoce zatížených kompozitních komponent je šroubový spoj, který je možné rozebrat pro případ opravy na rozdíl od lepeného spoje. Kompozitní konstrukce se tradičně dimenzují tak, aby během provozu nedošlo k porušení první vrstvy laminátu, nicméně důležité je taky poznat chování laminátu po porušení první vrstvy. Pro strukturální analýzu nejenom spojů, ale také dalších komponent se používá metoda konečných prvků a protože moderní nelineání řešiče jsou schopné modelovat chování laminátu po porušení první vrstvy, tato schopnost jednoho z nich byla využita v této práci při zkoumaní chování sklolaminátu spojeného s hliníkovou částí šrouby. Konečno-prvkové modely dvou spojů kovové a kompozitní části konstrukce schopné popsat progresivní porušování laminátu byly postaveny s využitím tří různých poruchových kritérií – kritéria maximálního napětí, kritéria Hill a kritéria Tsai-Wu. Problém byl řešen s využitím řešiče Nastran. Křivky síla-posuv, tuhost-posuv a hodnoty zatížení při hraničním posuvu byly porov-nány s výsledky experimentů. Jelikož faktor zbytkové tuhosti ovlivňuje výsledky ana-lýzy progresivního porušování, byly provedeny citlivostní studie zkoumajíci vliv faktoru na přesnost a stabilitu výpočtu. Shoda výpočtu s experimentem v případe prvního šroubového spoje je méně uspokojivá, nicméně shoda v případě druhého spoje, který má zesilující tenkou ocelovou destičku na spodní straně, je podstatně lepší. Vý-borná shoda je zejména při použití interaktivních kritérií Hill a Tsai-Wu.Nowadays, one of the method for joining especially thick and highly loaded composite components is mechanically fastened bolted joint which allows disassembly of compo-nents e.g. for repair unlike adhesively bonded joint. Traditional sizing method is first-ply-failure, however prediction post first-ply-failure behavior is important too. For structural analysis of the joints as well as for other components is widely used the finite element method. Since modern nonlinear solvers have capability for investigation post first-ply-failure behavior of laminate, this capability of one of them was used in this thesis for investigation of mechanical behavior of laminate made of GFRP layers which was joined to aluminium bracket using bolts. Progressive damage finite element models of two metal-to-composite joints were built in order to determine post first-ply-failure behaviour using three different failure criteria - maximum stress, Hill and Tsai-Wu using Nastran solver. Force-displacement curves, stiffness-displacement curves and values of loads at ultimate displacement were compared with experimental data. As residual stiffness factor influences the results of progressive failure analysis, sensitivity studies of the factor were done, in which accuracy and achieving conver-gence were investigated. In the case of the first joint an agreement is less satisfying, however, the agreement in the case of the second joint, which has a thin steel reinforc-ing plate on its bottom side, is considerably better. Excellent agreement is especially with interactive criteria Hill and Tsai-Wu.

Idealisation error control for aerospace virtual structural testing

This thesis addresses idealisation error control for the nonlinear finite element method. The focus is on accurate failure prediction of mid-size aerospace structures. The objective is the development of technologies that shorten the certification process of new airplanes, by replacing expensive and time consuming testing with reliable calculation methods. The SAFESA (Safe Structural Analysis) approach was applied to the collapse analyses of stiffened metal panels. ABAQUS/Standard was thereby the utilised nonlinear solver. Because the original SAFESA procedure is tailored for linear analyses, the methodology needed an update. The first analysis case is a stiffened panel compression test which was arranged as a lecture demonstration at Cranfield University. The analysis behaviour is highly nonlinear due to the thin-walled properties of the panel. The second analysis investigates an Airbus compression panel. Until failure, the panel behaves geometrically less complicated because the major load bearing parts are thick-walled and bend smoothly. The main research work is the critical analysis of important modelling assumptions concerning the used material model, boundary conditions and geometrical imperfections. In both cases, the method helped to identify idealisation errors and to build a reliable FEM model. In order to deal with the nonlinear error sources, minor extensions to the original method had to be made. The major achievement is the development of the first expert system which applies the idealisation error control methodology. CAD data import, geometry visualization, a knowledge-based decision making advisor and audit trail functionality were implemented. The expert system leads the user through a step-by-step idealisation process. Each decision is documented and a confidence level must be supplied. This way, every uncertainty is flagged out as potential error source. An interactive interface was created, which provides the user with expert advice on how to treat the idealisation errors. The software has been validated and shown to meet the program objectives.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Chandra News

The Chandra Newsletter contains articles about the CXC and the Chandra mission. The Chandra Newsletter appears once a year and is edited by Paul J. Green, with editorial assistance and layout by Evan Tingle. We welcome contributions from readers. Comments on the newsletter, or corrections and additions to the hardcopy mailing list should be sent to: [email protected]

Proceedings of the Belgian-Dutch IABSE Young Engineers Colloquium 2019:YEC2019

The proceedings contain 35 papers. The topics discussed include: fatigue monitoring of railway bridges by means of virtual sensing; steel-supported glazed atrium roof between two adjacent existing buildings; the Boekelose bridge: an innovative structure; case study of rail-bridge interaction of a large span railway viaduct in riga; probabilistic approach to evaluate fatigue safety status in steel railway bridges; buckling design approach for unstiffened curved plates in uniform shear; finite element modeling of residual welding stresses in an orthotropic steel bridge component; uniformly loaded tensegrity bridge design via morphological indicators method; tensile and shear resistance of bolted connectors in steel-FRP hybrid beams; and parametric analysis of rib distortion induced stress concentration at rib-to-crossbeam joint.</p

NASA Tech Briefs, September 2011

Topics covered include: Fused Reality for Enhanced Flight Test Capabilities; Thermography to Inspect Insulation of Large Cryogenic Tanks; Crush Test Abuse Stand; Test Generator for MATLAB Simulations; Dynamic Monitoring of Cleanroom Fallout Using an Air Particle Counter; Enhancement to Non-Contacting Stress Measurement of Blade Vibration Frequency; Positively Verifying Mating of Previously Unverifiable Flight Connectors; Radiation-Tolerant Intelligent Memory Stack - RTIMS; Ultra-Low-Dropout Linear Regulator; Excitation of a Parallel Plate Waveguide by an Array of Rectangular Waveguides; FPGA for Power Control of MSL Avionics; UAVSAR Active Electronically Scanned Array; Lockout/Tagout (LOTO) Simulator; Silicon Carbide Mounts for Fabry-Perot Interferometers; Measuring the In-Process Figure, Final Prescription, and System Alignment of Large; Optics and Segmented Mirrors Using Lidar Metrology; Fiber-Reinforced Reactive Nano-Epoxy Composites; Polymerization Initiated at the Sidewalls of Carbon Nanotubes; Metal-Matrix/Hollow-Ceramic-Sphere Composites; Piezoelectrically Enhanced Photocathodes; Iridium-Doped Ruthenium Oxide Catalyst for Oxygen Evolution; Improved Mo-Re VPS Alloys for High-Temperature Uses; Data Service Provider Cost Estimation Tool; Hybrid Power Management-Based Vehicle Architecture; Force Limit System; Levitated Duct Fan (LDF) Aircraft Auxiliary Generator; Compact, Two-Sided Structural Cold Plate Configuration; AN Fitting Reconditioning Tool; Active Response Gravity Offload System; Method and Apparatus for Forming Nanodroplets; Rapid Detection of the Varicella Zoster Virus in Saliva; Improved Devices for Collecting Sweat for Chemical Analysis; Phase-Controlled Magnetic Mirror for Wavefront Correction; and Frame-Transfer Gating Raman Spectroscopy for Time-Resolved Multiscalar Combustion Diagnostics