复试专业课课件结构力学jglxyy

1、STRUCTURAL MECHANICS结 构 力 学武汉理工大学物流工程学院 赵章焰Textbook: 普通高等教育“十一五”国家级规划教材 Structural Mechanics 包世华主编 2006References：结构力学教程 龙驭求等主编，高等教育出版社 2001 结构力学王重华主编， 人民交通出版社 支秉琛主编 清华大学出版社Fig.1 Main Teaching Building IntroductionFig.2 Introduction Introduction IntroductionIntroductionIntroductionIntroduction长江三峡工程

2、IntroductionIntroduction中国民航飞机Introduction宇宙飞船IntroductionChapter 1 IntroductionStructural MechanicsFrame or member which carries the load is referred to as a structure in engineering. i.e. Cranes jib; support frame of crane; support frame of civil construction. To study the internal forces of the s

3、tructure is the aim to this course.The structures in engineering are very complex (ity), so we must simplify the structures in several aspects.Introduction1.1 Computing ModelThe following factors are taken into account: the width of the walls (b) is very small comparison with the length of the beam

4、(l). The beam cant move in horizontal direction because of friction between the beam and walls, but it can enlong or shrink (age) due to change of temperature. the beam is represented by a line IntroductionIntroductionComputing modelIntroductionIntroductionworkshoptrussCRANEHow to simplify is a very

5、 important problem. We can do it from three aspects as following: 1. Simplification of Members Introduction2. Simplification of Joints When the members are connected together, the mutual displacements of the members are restrained. The connection point is called joint .There are two types joint. Hin

6、ge Joint. (Small resistance in bending) A hinge joint restrains the translation of one member relative to the others , the members can have independent free rotations about the centre of the hinge Rigid Joint The members form a monolithic body, they can move and translate as a group, but can not mov

7、e with respect to each other.IntroductionIntroduction Combination Joint ABCDEFGA：Rigid jointB、D：Hinge jointC：Combination jointBF、CD Hinge joint， BC、CF Rigid joint3. Simplification of supports Link support Hinge Support Introduction Fixed support Fixed direction support (定向支座) IntroductionAMAVAHA4、Si

8、mplification of load（1）Body load：body load can be simplified as line-load. Dead load, for instance.（2）surface load：surface load can be simplified as concentrated load or line load。For example, wind, snow load, and equipment.Introduction1.2 Classification of structures in dimensions domain : Structur

9、es can be classified into plane stru. And space stru. If members of the stru. are in a plane, its loads are also in the same plane .It is called plenary stru. If members are not in a plane or its loads are not lie in the same plane Introduction In Restraints Statically determinate stru. Statically i

10、ndeterminate stru. Unstable stru.IntroductionIntroduction1.3 Plenary framed structuresPlenary framed structures can be divided into the following forms梁拱桁架刚架组合结构 (1)、beam (2)、arch(3)、truss(4)、rigid frame(5)、composite structureIntroduction1.4 Classifications of loads Duration of application :Dead loa

11、d: dead load act on structure for ever. Its weight.Dead loads are those whose magnitudes remain constant and whose position doses not change. (existence forever)Live load: live load are those whose magnitude and position change.Live load contains movable load and moving load.Movable load are those which position can change:i.e. snow, person on structure. Furniture on a house. Moving load is meant by load can be moved by their own power.i.e. trolley of crane. (existence short time) Introduction(2)