{"id":593,"date":"2013-06-27T17:52:57","date_gmt":"2013-06-27T16:52:57","guid":{"rendered":"http:\/\/blogs.bath.ac.uk\/structures\/?p=593"},"modified":"2013-06-27T17:52:57","modified_gmt":"2013-06-27T16:52:57","slug":"question-18","status":"publish","type":"post","link":"https:\/\/blogs.bath.ac.uk\/structures\/2013\/06\/27\/question-18\/","title":{"rendered":"Question 18"},"content":{"rendered":"

Here is a question from \u00a0structures 2 but i'm sure \u00a0first years will \u00a0get it \u00a0right.<\/p>\n

\"question18\"<\/a><\/p>\n

Question: \u00a0Which \u00a0BMD is the \u00a0correct for the cantilever beam \u00a0shown?<\/strong><\/p>\n

Solution: Lets \u00a0start from the point \u00a0where the load is \u00a0applied. It might help\u00a0 if you\u00a0 sketch the problem and mark a\u00a0 line across the structure showing the\u00a0 direction of the\u00a0 applied load<\/p>\n

    \n
  1. The \u00a0bending moment will increases \u00a0linearly when we move away from the load ( we are moving \u00a0left) - all \u00a0diagrams \u00a0show \u00a0this!<\/li>\n
  2. As we move \u00a0down the vertical member on the \u00a0left \u00a0hand-side the \u00a0moment is constant as we are always the same perpendicular distance \u00a0from \u00a0the direction of the load.\n
      \n
    1. \n
        \n
      • Note that at the corner the BMD are both on the \u00a0outside as there is tension on this face.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<\/li>\n
      • As we move along the bottom beam ( left to midpoint) we get closer and closer to the \u00a0direction of the applied load so the \u00a0moment \u00a0decreases linearly<\/li>\n
      • As we \u00a0go past the \u00a0midpoint on the bottom beam \u00a0the bottom beam we get further \u00a0away \u00a0form the direction of the applied load and hence the moment increases linearly-only diagrams C & D show this.<\/li>\n
      • If \u00a0we \u00a0move \u00a0up \u00a0the \u00a0vertical member on the right hand side we \u00a0stay a constant perpendicular distance \u00a0form the direction of load and so the moment is constant - the moment is on the \u00a0inside of the member\u00a0 as this is\u00a0 the face where\u00a0 we have\u00a0 tension. \u2013 Only diagram D shows this.<\/li>\n<\/ol>\n

        Lastly as we move along\u00a0 the\u00a0 top beam (right to left)\u00a0 the moment\u00a0 must\u00a0 become less negative and reach \u00a0zero at the\u00a0 point where we are inline\u00a0 with the direction of load, when\u00a0 we\u00a0 have travelled\u00a0 past\u00a0 this\u00a0 towards the\u00a0 support the moment the moment increases and becomes\u00a0 positive indicating a region of hogging bending ( tension on top face) near the\u00a0 support<\/p>\n","protected":false},"excerpt":{"rendered":"

        Here is a question from \u00a0structures 2 but i'm sure \u00a0first years will \u00a0get it \u00a0right. Question: \u00a0Which \u00a0BMD is the \u00a0correct for the cantilever beam \u00a0shown? Solution: Lets \u00a0start from the point \u00a0where the load is \u00a0applied. It might...<\/p>\n","protected":false},"author":203,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[4,11],"tags":[],"class_list":["post-593","post","type-post","status-publish","format-standard","hentry","category-beams","category-st1"],"acf":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/blogs.bath.ac.uk\/structures\/wp-json\/wp\/v2\/posts\/593","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.bath.ac.uk\/structures\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.bath.ac.uk\/structures\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.bath.ac.uk\/structures\/wp-json\/wp\/v2\/users\/203"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.bath.ac.uk\/structures\/wp-json\/wp\/v2\/comments?post=593"}],"version-history":[{"count":0,"href":"https:\/\/blogs.bath.ac.uk\/structures\/wp-json\/wp\/v2\/posts\/593\/revisions"}],"wp:attachment":[{"href":"https:\/\/blogs.bath.ac.uk\/structures\/wp-json\/wp\/v2\/media?parent=593"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.bath.ac.uk\/structures\/wp-json\/wp\/v2\/categories?post=593"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.bath.ac.uk\/structures\/wp-json\/wp\/v2\/tags?post=593"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}