{"id":778,"date":"2013-04-21T21:36:31","date_gmt":"2013-04-22T02:36:31","guid":{"rendered":"http:\/\/amymakesstuff.com\/?p=778"},"modified":"2013-04-21T21:36:31","modified_gmt":"2013-04-22T02:36:31","slug":"fatigue-a-study-of-flexures-in-a-scooter","status":"publish","type":"post","link":"https:\/\/amymakesstuff.com\/?p=778","title":{"rendered":"Fatigue: a study of flexures in a scooter"},"content":{"rendered":"<p>Introducing, Fatigue, my preemptively-named flexure-based scooter.<\/p>\n<figure id=\"attachment_780\" aria-describedby=\"caption-attachment-780\" style=\"width: 600px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2769.jpg?resize=600%2C715\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full wp-image-780\" alt=\"fingers crossed for gradual, not sudden, failure\" src=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2769.jpg?resize=600%2C715\" width=\"600\" height=\"715\" srcset=\"https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2769.jpg?w=859&amp;ssl=1 859w, https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2769.jpg?resize=252%2C300&amp;ssl=1 252w, https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2769.jpg?resize=768%2C916&amp;ssl=1 768w\" sizes=\"(max-width: 600px) 100vw, 600px\" data-recalc-dims=\"1\" \/><\/a><figcaption id=\"caption-attachment-780\" class=\"wp-caption-text\">fingers crossed for gradual, not sudden, failure<\/figcaption><\/figure>\n<p>You can see how a flexure is perfect for the rear brake, which has quite limited travel. Luckily, it also doesn&#8217;t see to many extreme forces. It is made from polycarbonate, about 0.1&#8243; thick.<\/p>\n<figure id=\"attachment_782\" aria-describedby=\"caption-attachment-782\" style=\"width: 600px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2771.jpg?resize=600%2C450\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full wp-image-782\" alt=\"rear brake\" src=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2771.jpg?resize=600%2C450\" width=\"600\" height=\"450\" srcset=\"https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2771.jpg?w=640&amp;ssl=1 640w, https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2771.jpg?resize=300%2C225&amp;ssl=1 300w\" sizes=\"(max-width: 600px) 100vw, 600px\" data-recalc-dims=\"1\" \/><\/a><figcaption id=\"caption-attachment-782\" class=\"wp-caption-text\">rear brake<\/figcaption><\/figure>\n<p>The pivot for the front fork however, needs to achieve relatively high deflection (to improve turning radius) AND it also sees lots of torsion (envision standing on the scooter deck, the deck slants to the right, and you try and stabilize by leaning the handlebars left, ouch). Needless to say, this current setup is not really optimized for high torsional stiffness. But it was pretty easy to make, and will suffice (for the near future).<\/p>\n<p>The two sets of wooden bars that are screwed into the flexure were added after test riding and realizing that without some constraint, the flexure was just not stiff enough.<\/p>\n<figure id=\"attachment_781\" aria-describedby=\"caption-attachment-781\" style=\"width: 480px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2770.jpg?resize=480%2C640\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full wp-image-781\" alt=\"stress test!\" src=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2770.jpg?resize=480%2C640\" width=\"480\" height=\"640\" srcset=\"https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2770.jpg?w=480&amp;ssl=1 480w, https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2770.jpg?resize=225%2C300&amp;ssl=1 225w\" sizes=\"(max-width: 480px) 100vw, 480px\" data-recalc-dims=\"1\" \/><\/a><figcaption id=\"caption-attachment-781\" class=\"wp-caption-text\">stress test!<\/figcaption><\/figure>\n<p>This was how I tested the idea of adding some bars to effectively shorten the flexure. There was a big hit to turning radius, but the torsional stiffness improved enough to be rideable.<\/p>\n<figure id=\"attachment_779\" aria-describedby=\"caption-attachment-779\" style=\"width: 480px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2767.jpg?resize=480%2C640\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full wp-image-779\" alt=\"lots of clamps\" src=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2767.jpg?resize=480%2C640\" width=\"480\" height=\"640\" srcset=\"https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2767.jpg?w=480&amp;ssl=1 480w, https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2767.jpg?resize=225%2C300&amp;ssl=1 225w\" sizes=\"(max-width: 480px) 100vw, 480px\" data-recalc-dims=\"1\" \/><\/a><figcaption id=\"caption-attachment-779\" class=\"wp-caption-text\">lots of clamps<\/figcaption><\/figure>\n<figure id=\"attachment_785\" aria-describedby=\"caption-attachment-785\" style=\"width: 600px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2775.jpg?resize=600%2C307\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full wp-image-785\" alt=\"turning radius\" src=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2775.jpg?resize=600%2C307\" width=\"600\" height=\"307\" srcset=\"https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2775.jpg?w=640&amp;ssl=1 640w, https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2775.jpg?resize=300%2C154&amp;ssl=1 300w\" sizes=\"(max-width: 600px) 100vw, 600px\" data-recalc-dims=\"1\" \/><\/a><figcaption id=\"caption-attachment-785\" class=\"wp-caption-text\">turning radius<\/figcaption><\/figure>\n<figure id=\"attachment_784\" aria-describedby=\"caption-attachment-784\" style=\"width: 600px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2773.jpg?resize=600%2C450\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full wp-image-784\" alt=\"bike seat clamp cam for locking the handlebars in place\" src=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2773.jpg?resize=600%2C450\" width=\"600\" height=\"450\" srcset=\"https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2773.jpg?w=640&amp;ssl=1 640w, https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2773.jpg?resize=300%2C225&amp;ssl=1 300w\" sizes=\"(max-width: 600px) 100vw, 600px\" data-recalc-dims=\"1\" \/><\/a><figcaption id=\"caption-attachment-784\" class=\"wp-caption-text\">bike seat clamp cam for locking the handlebars in place<\/figcaption><\/figure>\n<figure id=\"attachment_783\" aria-describedby=\"caption-attachment-783\" style=\"width: 600px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2772.jpg?resize=600%2C293\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full wp-image-783\" alt=\"it folds.\" src=\"http:\/\/amymakesstuffdotcom.files.wordpress.com\/2013\/04\/img_2772.jpg?resize=600%2C293\" width=\"600\" height=\"293\" srcset=\"https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2772.jpg?w=640&amp;ssl=1 640w, https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2772.jpg?resize=300%2C147&amp;ssl=1 300w\" sizes=\"(max-width: 600px) 100vw, 600px\" data-recalc-dims=\"1\" \/><\/a><figcaption id=\"caption-attachment-783\" class=\"wp-caption-text\">it folds.<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Introducing, Fatigue, my preemptively-named flexure-based scooter. You can see how a flexure is perfect for the rear brake, which has quite limited travel. Luckily, it also doesn&#8217;t see to many extreme forces. It is made from polycarbonate, about 0.1&#8243; thick. The pivot for the front fork however, needs to achieve relatively high deflection (to improve [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":780,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[9,19],"tags":[71,85,86,89,118,172,228],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/amymakesstuff.com\/wp-content\/uploads\/2013\/04\/img_2769.jpg?fit=859%2C1024&ssl=1","_links":{"self":[{"href":"https:\/\/amymakesstuff.com\/index.php?rest_route=\/wp\/v2\/posts\/778"}],"collection":[{"href":"https:\/\/amymakesstuff.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/amymakesstuff.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/amymakesstuff.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/amymakesstuff.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=778"}],"version-history":[{"count":0,"href":"https:\/\/amymakesstuff.com\/index.php?rest_route=\/wp\/v2\/posts\/778\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/amymakesstuff.com\/index.php?rest_route=\/wp\/v2\/media\/780"}],"wp:attachment":[{"href":"https:\/\/amymakesstuff.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=778"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/amymakesstuff.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=778"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/amymakesstuff.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=778"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}