Please turn on javascript in your browser to play chess.
Science Forum

Science Forum

  1. Standard member sonhouse
    Fast and Curious
    27 Sep '16 11:22
    New for me anyway, semiconductors generating electricity when bent. Not Piezoelectricity where the electricity is generated by compression, Different effect:

    http://phys.org/news/2016-09-semiconductors-electricity.html
  2. Standard member apathist
    looking for loot
    28 Sep '16 09:32 / 1 edit
    Apparently it is a piezoelectric effect modified by a strain gradient (wiki). I don't know what a strain gradient is.
  3. Standard member sonhouse
    Fast and Curious
    28 Sep '16 14:49 / 1 edit
    Originally posted by apathist
    Apparently it is a piezoelectric effect modified by a strain gradient (wiki). I don't know what a strain gradient is.
    Gradient is just how the stress varies across a depth, so when bent, the inside curve may have more stress than the outside, which can be seen by laser interferometry.

    Here are a bunch of images where you can see the distortions and stresses with this technique:

    https://www.google.com/search?q=optical+interferometry+IMAGES&rlz=1C1WPZB_enUS596US596&espv=2&biw=1920&bih=974&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjWuq-hp7LPAhWJWj4KHUaUBb8QsAQIPg

    These devices can tell how well a telescope mirror is ground, and whether there is strain on the device.