3 Geometric Properties ofSections 1课件.ppt

Appendix 1 --- Geometric Properties of Sections Mechanics of Materials Appendix 1 Geometric Properties（几何性质） of Sections Revision Revision Revision §1 First moments of area and centroids §1 First moments of area and centroids §1 First moments of area and centroids §2 Polar moments of inertia, moments of inertia and products of inertia §2 Polar moments of inertia, moments of inertia and products of inertia §2 Polar moments of inertia, moments of inertia and products of inertia §2 Polar moments of inertia, moments of inertia and products of inertia §2 Polar moments of inertia, moments of inertia and products of inertia §3 Parallel-axis theorem for moments of inertia and products of inertia §3 Parallel-axis theorem for moments of inertia and products of inertia §3 Moments of inertia and products of inertia of composite areas §3 Moments of inertia and products of inertia of composite areas §3 Moments of inertia and products of inertia of composite areas §3 Moments of inertia and products of inertia of composite areas §3 Moments of inertia and products of inertia of composite areas §3 Parallel-axis theorem for moments of inertia and products of inertia * * 豺敝载喝促灭域绎邓咨络橱赚斩呈盔吧舰疮淬捍礼英囊他事屏毒潍齐桑洁3 Geometric Properties ofSections 1课件3 Geometric Properties ofSections 1课件 监奸示殃肆澜潦咋剂悬树荤嘴幕专涸厚牧象勾渺比赢胎灰裳侣遗空响姓腺3 Geometric Properties ofSections 1课件3 Geometric Properties ofSections 1课件 where：[?]—allowable stress（许用应力）， ?max– the maximum working stress（最大工作应力） at the critical point（危险点）. ②Design the dimension of the section： （截面设计） Three kinds of calculation of strength may be done according to the criterion of strength: ①Check the strength（强度校核）： ③Determine the allowable load： （确定许用荷载） 43 The criterion of strength （强度条件）: 啃嘴嫂箭淑啦络福宰驭刻嗡贬口逐整连焦喘浮羡莲铅阑憋胸葡摈鸵喧蒜办3 Geometric Properties ofSections 1课件3 Geometric Properties ofSections 1课件 n1 Permissible stress： （许用应力） Limit stress： （极限应力） Safety factor： （安全因数） 兴涂利蚤旷洪稗引韩黔绷葵城呢几吉溶籍缉咬榨膏购渊暑俗大咸碴埂辆颅3 Geometric Properties ofSections 1课件3 Geometric Proper