<p> 根据平衡条件,其轴向受的外力<img src="http://que-oss.fenziquan.com/web/akimg/asource/2014103116081444894.jpg">必与轴向内力<img src="http://que-oss.fenziquan.com/web/akimg/asource/2014103116082695779.jpg">相等。对于薄壳体,可近似认为内直径<img src="http://que-oss.fenziquan.com/web/akimg/asource/2014103116085367767.jpg">等与壳体的中面直径D<br> <img src="http://que-oss.fenziquan.com/web/akimg/asource/2014103116105928354.jpg"></p>