Eann Patterson

Eann Patterson

Engineer, educator & author. I hold the AA Griffith Chair in Structural Materials & Mechanics at the University of Liverpool. Read my blog at RealizeEngineering.Wordpress.com to find out more.

Location Liverpool

Activity

  • I am sorry to hear that you feel it is beyond you. You should be follow later steps without having understood these worked examples. So, keep going!

  • I cannot find the error in the pdf. Can you tell me more?

  • Yes, there are quite a few parallels. I have posted a couple of posts on my blog on this topic. See, for example:
    https://realizeengineering.wordpress.com/2013/04/03/noise-transfer/
    https://realizeengineering.wordpress.com/2013/04/17/sonic-screwdrivers/

  • Yes, I am planning to start a new PhD project on fracture properties of timber next academic year which, in part, is motivated by the increase use of timber in tall buildings.

  • Yes, there certainly used to be - I remember seeing it when I was much younger. I think it's the one next to Battersea Park?

  • Thank you. It would be good to see some more designs!

  • Thank you for spotting the typos. I found two and have corrected them.

  • This a bit too much information; but it's good to hear that you have got set up to try out FEA.

  • It might be that most ancient structures fell down long ago and the only ones left are the very best. I expect that the best modern day ones will also survive for centuries. However, it is very expensive to design everything to survive for thousands of years!

  • Yes, this approach is being used in a wide range of engineering fields, such as aerospace engineering.

  • Yes, it is why troops break step but you wouldn't expect a random collection of pedestrians to produce the same effect.

  • Here is a quick link to the collection of editorials mentioned in the audio clip: http://journals.sagepub.com/topic/collections/sdj-1-golden_anniversary_editorials/sdj

  • I am glad you found the course rewarding. I hope to see you again either on-line or on one of our campuses in Liverpool, London or Suzhou.

  • I have not come across that particular programme. There are lots of integrated analysis systems for structures. Some of them are specialised for particular industries, such as aerospace or civil engineering, others are more generalised.

  • If the probability of failure is high then we need to redesign the structure to lower the probability. This might mean doing tests or research to remove some of the unknowns.

  • Yes, it does appear to act in a similar way to drilling a hole to stop a crack, except that the crack is not arrested. The crack's advance is slowed down but we have not managed to arrest a crack in this way.

  • I am still reading comments on previous weeks so if you ask questions I will try to answer them.

  • Welcome to the course. We are in the last week which is week 5; however, I am scanning through comments made in other weeks, so feel free to ask questions or make comments and one of us will answer them. I hope you make it to the end before it closes to free admission in three weeks time!

  • Yes, but be careful with the word 'show' because some deflections might so small as to be invisible with the naked eye.

  • I'm not sure whether that's poor design or your technique, or a bit of both?

  • We use the LISA code when we are teaching a short course on structural integrity to scientists. Its a free download at http://www.lisa-fet.com/

    I have never tried it on an iMAC.

  • I have co-authored one book entitled 'The Entropy Vector: Connecting Science and Business' with Bob Handscombe. We wrote it a long time ago. See: http://www.worldscientific.com/worldscibooks/10.1142/5365

    However, it does not deal with this subject directly. I wrote a piece for the Citizens of Everywhere project a few months ago...

  • I don't follow what you mean.

  • Maybe some types of tofu would work as an alternative. Though I have not tried it in this experiment and would not recommend using the stinky tofu that I have come across in Taiwan!

  • No. Yield line analysis assumes possible collapse modes for a structure based on the formation of plastic hinges or yield lines. It does deal with the fracture of the material.

  • if you are in France, you should try Cantal or Comte cheese.

  • I don't know. Before I could answer, I would need to know a lot more about the geometry of the structure, the materials and loading conditions. So I am hoping yours was a rhetorical question?

  • If you want even more heavy reading material, then some of our work on cracks in titanium has been published under the title: Quantitative measurement of plastic strain field at a crack tip, by Y Yang, M Crimp, RA Tomlinson & EA Patterson in the Proceedings of the Royal Society A, 468:2399-2415, 2012. A download is available at...

  • Some of latest research was published last year in the journal: Experimental Mechanics under the title: High temperature vibratory response of Hastelloy-X: stereo-DIC measurements and image decomposition, by RB Berke, CM Sebastian, R Chona, EA Patterson & J Lambros. It's currently available as a free download from the publishers if you want some extra heavy...

  • By coincidence I wrote next week's post for my blog about GIGO. So, yes I agree.

  • Yes, that's a nice example but I fear we might be revealing our age.

  • Yes, titanium has a material response similar to steel and aluminium but offers higher performance per unit mass. However, as you point out, it is expensive. We have been performing research on fatigue crack growth in titanium though not connected to the work on hypersonic flight mentioned above.

  • Yes, the gradient of the elastic portion of the stress-strain curve and the yield point will change with temperature. The level of change varies from one material to another. So this has to be accounted for in the design of aircraft. We are currently working the behaviour of aircraft panels during hypersonic flight when temperatures up to 2000 degrees can...

  • No, see my response to your earlier comment.

  • I didn't say that bonds break and re-form in elastic deflections. Dislocation movement and bond breaking then re-forming are associated with permanent or plastic deformation. However, plastic deformation can be very local in a structure so that the remainder of the structure behaves elastically. It is rare for an entire structure to transition from elastic...

  • Yes. Digital computers might be able to handle a large number of variables but the creative process of generating innovative designs still requires our analogue brains and graphical representations, such as Mohr's circles, allow us to interprete the analysis and understand the stress system.

  • Yes, you are right. It is missing. Our graphic designer will work on it later today.

  • Surely, if the water forms a thin film then it is no longer a droplet. A droplet is a very small drop and by definition a drop is 'a small round or pear-shaped portion of liquid that hangs or falls or adheres to a surface' according to the OED.

  • I had already used the bungee cord in another example and want something different to avoid confusion...

  • We don't have an acoustic room or recording studio so we have to make do with what's available. I want to show the steps involved in the analysis rather than the short-cuts that will only work in specific circumstances.

  • I can't answer that question. Universities make proposals to FutureLearn for new courses but as far as I am aware there is no grand plan. The choice available to you depends on what the educators fancy producing.

  • Thank you. I have made the corrections.