? Users may download and print one copy of any publication from the public portal for the purpose of private study or research. ? You may not further distribute the material or use it for any profit-making activity or commercial gain ? You may freely distribute the URL identifying the publication in the public portal ? Take down policy If you believe that this document breaches copyright please contact us at vbn@aub.aau.dk providing details, and we will remove access to the work immediately and investigate your claim.

Dynamics of structures

Inconel 718 superalloy has been fabricated by selective laser melting technology (SLM). Its microstructure and mechanical properties were studied under solution+aging (SA) standard heat treatment, homogenization+solution+aging (HSA) standard heat treatment and as-fabricated conditions. Precipitated phases and microstructures were examined using OM, SEM, TEM and X-ray analysis methods. The fine dendrite structures with an average dendrite arm spacing of approximately 698 nm accompanying some interdendritic Laves phases and carbide particles can be observed in the as-fabricated materials. After standard heat treatments, dendrite microstructures are substituted by recrystallization grains, and Laves phases also dissolve into the matrix to precipitate strengthening phases and δ particles. The test values of all specimens meet Aerospace Material Specification for cast Inconel 718 alloy, and the transgranular ductile fracture mode exists for the three conditions. The strength and hardness of heat-treated SLM materials increase and are comparable with wrought Inconel 718 alloy, whereas their ductility decreases significantly compared with the as-fabricated material. This is because of the precipitation of fine γˊ and γ〞strengthening phases and needle-like δ phases. For the as-fabricated alloy, the formation of finer dislocated cellular structures that develop into a ductile dimple fracture shows excellent ductility. Due to dislocation pinning from γˊ and γ〞strengthening phases and the impediment of dislocation motion caused by the needle-like δ phases, the ductility of the SA materials decreases and causes a transgranular fracture, compared with the as-fabricated samples.

Effect of standard heat treatment on the microstructure and mechanical properties of selective laser melting manufactured Inconel 718 superalloy

Bending, buckling and free vibration of laminated composite and sandwich beams: A critical review of literature

Bending of Euler–Bernoulli beams using Eringen’s integral formulation: A paradox resolved

Nonlocal elasticity in nanobeams: the stress-driven integral model

Due to economic reasons the industry is seeking new lightweight solutions for large steel structures. However, when moving from traditional steel plate thicknesses, i.e. 5 mm or larger, to thinner ones, the fatigue design becomes challenging due to larger initial distortions caused by welding. The fatigue assessment methods used for thicker welded structures are not fully validated for thinner ones. This paper deals with the fatigue assessment of large thin-walled structures starting from the global response analysis of a whole structure to the stiffened panel and finally welded joint. A modern cruise ship is used as an example case, where traditional superstructure deck plate thickness of 5 mm is replaced by 3 mm. The influence of initial distortion at different levels of structural analysis is studied using geometrically nonlinear finite element (FE) analysis. For the lowest level of analysis, i.e. small welded joint, the experiments have been carried out including geometry measurements and fatigue tests. It is shown that for a large thin-walled structure the global response analysis can be carried out with acceptable accuracy using ideally straight plates and geometrically linear FE analysis. For intermediate level of analysis, i.e. stiffened panel, the analysis can also be geometrically linear, but the actual shape of the plates influences the structural stresses near welds significantly. When analyzing small welded specimens to define experimental fatigue strength, both the actual shape and the geometrically nonlinear FE analysis are needed in order to capture the straightening effect and to obtain the correct structural stress.

Fatigue Assessment of Large Thin-Walled Structures with Initial Distortions

Beams with large thin-walled cross sections are not generally following the classical beam theories such as Euler-Bernoulli and Timoshenko theories. In free vibration, the cross section is deformed by the inertia induced body loads. These deformations may have significant effect on the beam modal frequencies, especially in applications involving non-structural masses. This paper presents a method to include the effect into vibration modal results obtained by the classical beam theories. Generalized mass and stiffness of the classical results are modified according to kinetic-, and strain energies of the cross section deformation. The method is validated in typical engineering case studies against fine mesh Finite Element Method and excellent agreement is found.

/pdf/free-flexural-vibration-of-symmetric-beams-with-inertia-2kgmt6ncov.pdf

Free flexural vibration of symmetric beams with inertia induced cross section deformations

Influence of shear-induced secondary bending on buckling of web-core sandwich panels

Cruise and Ferry Experience program for Future Passenger Ship Designers

Present paper gives an overview of the factors that affect the strength and structural design of advanced thin-walled marine structures with reduced plate thickness or alternative topologies to those used today in marine industry. Due to production-induced initial deformations and resulting geometrical non-linearity, the classical division between primary, secondary and tertiary responses becomes strongly coupled. Volume-averaged, non-linear response of structural element can be used to define the structural stress strain relation that enables analysis at the next, larger, length scale. This, today’s standard homogenization process needs to be complemented with localization, where the stresses are assessed at the details, such as welds for fatigue analysis. Due to this, the production-induced initial distortions need to be considered with high accuracy. Another key question is the length-scale interaction in terms of continuum description. Non-classical continuum mechanics are needed when consequtive scales are close. Strain-gradients are used to increase the accuracy of the kinematical description of beams, plates and shells. The paper presents examples of stiffened and sandwich panels covering limit states such as fatigue, non-linear buckling and fracture.

/pdf/limit-state-analyses-in-design-of-thin-walled-marine-d0tqutzt1s.pdf

Limit State Analyses in Design of Thin-Walled Marine Structures: Some Aspects on Length-Scales

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Jani Romanoff

Author Tools

Chat about Author