User:Khakigreen/sandbox
Article Evaluation (Week 3)
Article Chosen: Conductive Heat Transfer
- Is everything in the article relevant to the article topic? Is there anything that distracted you?
- I would agree that everything in this article is relevant to the topic however I was distracted a little bit when the article spoke about detailed classifications in regards to smooth and solid surfaces.
- Is the article neutral? Are there any claims, or frames, that appear heavily biased toward a particular position?
- No, the article appears neutral to me.
- Are there viewpoints that are overrepresented, or underrepresented?
- I feel like the Free or Natural convection section went into a little more detail than the forced convection section.
- Check a few citations. Do the links work? Does the source support the claims in the article?
- The links do work and the items that I could check seem to support the article.
- Is each fact referenced with an appropriate, reliable reference? Where does the information come from? Are these neutral sources? If biased, is that bias noted?
- No not all of the facts are referenced however some are. The sources appear to be neutral.
- Is any information out of date? Is anything missing that could be added?
- No I feel the article encompass everything as far as my knowledge.
- Check out the Talk page of the article. What kinds of conversations, if any, are going on behind the scenes about how to represent this topic?
- There are a lot of conversations going on behind the scenes. Some back and fourth in regards to the opening paragraph and definition of convection.
- How is the article rated? Is it a part of any WikiProjects?
- The project is rated as Start-Class and is within scope of the WikiProject Meteorology.
- How does the way Wikipedia discusses this topic differ from the way we've talked about it in class?
- This article goes a lot deeper than our classroom discussions but not in a bad way. What we have leaned in class is just relevant to the welding topic.
Potential Topics (Week 4)
Fatigue of a Welded Joint
I was not able to find information regarding fatigue of a welded joint. Ideally this would be a subheading under the Welded Joint page. I would be able to speak a little but about metallurgy plus information which will be presented in lecture on 11/29.
Welding Distortion
I was not able to find any information on this topic either in Wikipedia. This may be a topic in itself where as my previous topic would be an add on. I would be able to link some topics such as Welding and Distortion. I do not have many sources on this topic to they will have to be researched but it is a fairly well known topic within manufacturing. We have not covered this topic in class but it is coming. I have discussed it in other classes as well as in application at work/industry.
Thermal Conduction
Thermal Conduction subheading "Applications" can be updated to include welding. Here we can expand a little but from the earlier portion of class and how it applies to welding and review various papers/studies.
Welding Cooling Rate
This may be a good topic because it is not represented on Wikipedia, however I do not have any good references other than class notes at this time so I will keep this as a low priority.
Instructor Comments
Adding an article on fatigue of welded joints would be excellent.
Fatigue of a Welded Joint (DRAFT)
Welding is a manufacturing method used to join various materials in order to form an assembly. During welding, joints are formed between two or more separate pieces of material. If this welded joint is subjected to cyclic loading, failure due to fatigue could result.[1] This cyclic loading, in addition to strains in the material, make up what is described as fatigue.[1] Throughout a welded assemblies life, cracks could initiate, propagate, and grow causing the assembly to fail even if these cyclic stresses are low and smaller than the base material and weld filler material yield stress.[1] Hence, the fatigue strength of a the welded joint does not correlate to the fatigue strength of the base material.[1] Incorporating design rules in the development phase can reduce failures due to fatigue in welded joints.[2]
Stress Life Method
Similar to high cycle fatigue analysis, the stress life method utilizing stress-cycle curves (also known as Wöhler curves) can be used to determine the strength of a welded joint under fatigue loading. Welded sample specimens undergo repeated loading at a specified stress amplitude, or fatigue strength, until the material fails.[3] This same test is then repeated with various stress amplitudes in order to determine its corresponding cycles, N, to failure. With the data collected, fatigue strength can be plotted against the corresponding number of cycles for a specific material, welded joint and loading.[3] From these curves, the endurance limit, finite-life and infinite-life region can then be determined.[3]
Factors Affecting Fatigue
Welding Residual Stresses
During the welding process, residual stresses can present themselves in the area of the weld, either in the heat affected zone or fusion zone. The mean stress, which a welded joint may see in application, can be altered due to the welding processes implementing residual stresses, changing the fatigue life and can scatter S-N laboratory testing results.[2] Welded assemblies, with geometrical imperfections, when connected through a welding process, can also introduce residual stresses.[2] Removal of residual stresses by stress relief methods can only be partially achieved.[2] Long range residual stresses can still remain in a welded joint even after some of these stress relief methods have been achieved.[2]
Member Thickness
An increase in thickness of a base material decreases the fatigue strength when a crack propagates from the toe of a welded joint.[2] This is due to an increase in residual stress concentrations in thick material cross sections.[2]
Material Type
All materials have varying physical and mechanical properties. As a materials ultimate tensile strength increases, this does not lead to an increase in fatigue strength.[2] This is not the case when evaluating materials that do not contain welded joints.[2] Therefore stress-cycle curves for welded joints cannot be correlated to the materials ultimate tensile strength. A majority of materials are still being studied, such as aluminum, however most design information was developed for structural steels.[2]
Welding Process
Many welding processes are available for various applications and environments. Unfortunately, stress-cycle curves are not available for all of these processes and still need to be developed so that proper fatigue analysis can be performed.[2] The most abundant process found in stress-cycle curves is developed from specimens prepared by arc welding.
Surrounding Environment
Prevention
Finite Element Analysis
References
- ^ a b c d e Tom., Lassen, (2013). Fatigue Life Analyses of Welded Structures : Flaws. Récho, Naman. Somerset: Wiley. ISBN 9781118614709. OCLC 929525641.
{{cite book}}: CS1 maint: extra punctuation (link) CS1 maint: multiple names: authors list (link) - ^ a b c d e f g h i j k Maddox, Stephen (January/March 2000). "Fatigue Design Ruled for Welded Structures". Progress in Structural Engineering and Materials. 2, Issue 1: 102–109 – via John Wiley & Sons, Ltd.
{{cite journal}}: Check date values in:|date=(help) - ^ a b c Gordon), Budynas, Richard G. (Richard (2008). Shigley's mechanical engineering design. Nisbett, J. Keith., Shigley, Joseph Edward. (8th ed ed.). Boston: McGraw-Hill. ISBN 9780073312606. OCLC 70836665.
{{cite book}}:|edition=has extra text (help)CS1 maint: multiple names: authors list (link) - ^ Khatib, Hamza (2016). "Using an Experimental Approach Based on Static Characterization Tests" (PDF). Contemporary Engineering Scienves. 9, no. 11: 513–530 – via Hikari Ltd.
- ^ Martin, T. "Fatigue Design of Welded Joints Using the Finite Element Method and the 2007 ASME Div. 2 Master Curve". Department of Industrial Engineering, University of Pharma (Italy).