【正文】 f Structural Systems and Elements系統(tǒng)結(jié)構(gòu)和元素的分類和作用Common rigid elements include beams, columns or struts, arches, flat plates, singly curved plates, and shells having a variety of different curvatures. Flexible elements include cables (straight and draped) and membranes(planar, singly curved, and doubly curved). In addition, there are a number of other types of structures that are derived from these elements(, frames, trsses, geodesic domes, nets, etc. )(figure )常見的剛性元件包括梁，柱，支撐，圓拱，平板，單向板彎曲面，具有不同的曲率的翹體。Trusses 桁架Trusses are structural members made by assembling short, straight members into triangulated patterns. The resultant （組合的, 合成的）structure is rigid as a result of the exact （精確的) way the individual line elements are positioned relative to one another. Some patterns (. a pattern of squares rather than triangles) do not necessarily yield a structure that is rigid (unless joints are treated in the same way as in framed structures). A truss posed of discrete elements is bent in an overall way under the action of an applied transverse loading in much the same way that a beam is bent. Individual truss members, however, are not subject to bending but are only either pressed or pulled upon. 桁架結(jié)構(gòu)構(gòu)件是通過短直桿組裝成三角形的圖案。個人桁架構(gòu)件，不能彎曲只能壓縮或拉后。這種類型的結(jié)構(gòu)不能進(jìn)行負(fù)載誘導(dǎo)伸長或任何明顯的拉伸（只需拉開塊發(fā)生故障）。如果制成剛性拱的形狀，它們可以承受的負(fù)載支座僅受軸向壓縮的同時并沒有發(fā)生彎曲。地震）。Horizontal plates can also be made by assembling patterns of short, rigid line elements. Threedimensional triangulation schemes are used to impart stiffness to the resultant assembly.水平板也可以通過組裝短，剛性線的模式。Cylindrical Shells and Vaults 柱形殼和拱頂Cylindrical barrel shells and vaults are examples of singly curvedplate structure. A barrel shell spans longitudinally such that the curve is perpendicular to the direction of the span. When fairly long, a barrel shell behaves much like a beam with a curved cross section. Barrel shells are invariably made of rigid materials (., reinforced concrete or steel). A vault, by contrast, is a singly curved structure that spans transversely. A vault can be conceived of as basically a continuous arch.柱形殼和拱頂 圓柱型的筒和拱頂都是單獨(dú)的弧形板式結(jié)構(gòu)的例子。相反的，儲藏庫是一個單獨(dú)的弧形結(jié)構(gòu)，橫向跨越。也許最常見的雙曲面結(jié)構(gòu)是球殼。圓頂結(jié)構(gòu)，可以由層疊塊或連續(xù)的剛性材料（鋼筋混凝土）組成。當(dāng)很簡單地拉索的任一端時，它假定了直板造型。索本身的自重產(chǎn)生這樣的懸鏈線，吊索可用于跨越非常大的距離。但是實(shí)際的表面將要作為一個組件的更小的段，因?yàn)榇蠖鄶?shù)膜通常僅適用于平板。強(qiáng)調(diào)皮膚的各種結(jié)構(gòu)的這種通用類型，然而，需要預(yù)拉伸皮膚施加各種條件的限制，可以形成的形狀。此外，張力通常誘導(dǎo)索頂裝置，使整個表面變成一種類型的伸展。有幾個基本的方法，其中可能會發(fā)生故障。在自身的重量和傾覆的作用下，可能只是失去了平衡。這種類型導(dǎo)致的坍塌總是涉及大型結(jié)構(gòu)本身的相對運(yùn)動。A third set of concerns deals with the strength and stiffness of constituent are many structure issues that revolve around the strength of ponent parts of a structure. These failures, which may or may not lead to total collapse, may be caused by excessive tension, pression, bending, shear, torsional, bearing forces, or deformations that are developed internally in the structure as a consequence of the applied loadings. Associated with each force state are internal stresses that actually exist within the fabric of the material itself. By carefully designing ponents in response to the force state present, the actual stresses developed in the ponents can be controlled to safe levels.第三組的關(guān)注處理的強(qiáng)度和剛度的結(jié)構(gòu)元素。通過仔細(xì)地設(shè)計(jì)組件的受力狀態(tài)，開發(fā)組件的實(shí)際應(yīng)力可以被控制到安全水平。一個不穩(wěn)定的結(jié)構(gòu)不會產(chǎn)生內(nèi)部的力量，往往恢復(fù)到原來的配置結(jié)構(gòu)。例如。這種特殊的結(jié)構(gòu)將在負(fù)載下瞬間崩潰。用來保證穩(wěn)定性的另一種方法是通過剪力墻。用于實(shí)現(xiàn)穩(wěn)定的最后一種方法是通過停止大角度變化，確保結(jié)構(gòu)之間的連接的性質(zhì)就是這樣原理的性質(zhì)，它們的角的關(guān)系仍然是一個恒定值。在一個結(jié)構(gòu)中，可以使用一個以上的方法（例如，具有兩個剛性接頭和對角線結(jié)構(gòu)），但顯然這涉及一定程度的冗余。在力法的步驟The steps in the force method在力法的步驟（1）Determine the degree of statical indeterminacy of the structure. Parameter n will be used to denote the degree of indeterminacy.（1）確定靜不定結(jié)構(gòu)的程度。編號從1到N的釋放的約束 （3）For a given released constraint j, introduce an unknown redundant force Xj corresponding to the type and direction of the released constraint. （3）基本體系沿多余未知力方向的位移應(yīng)與原結(jié)構(gòu)位移相同 （4）Apply the given loading or imposed deformation to the primary system. Calculate displacements due to the given loading at each of the released constraints in the primary system. These displacements are called Δ1P , Δ2P , ΔnP .., . （4）將給定的加載或主系統(tǒng)的附加變形。這些位移被稱為，(6)Solve for redundant forces X1 through Xn by imposing the patibility conditions of the original conditions transform the primary system back to the original structure by finding the bination of redundant forces that make displacement at each of the released constraints equal to conditions are expressed mathematically as follow This is a system of n linear equations in n unknows,The displacements arw all unknow forces are can thus be seen that the name of force method was given to this method because its primary putational task is to calculate unknown forces,.,the redundant forces X1 through Xn.（6）解決多余力X1到XN利用原結(jié)構(gòu)的相容性條件。由此可以看出，力方法的名稱分配給該方法由于其計(jì)算的基本任務(wù)是計(jì)算未知的力量，即，多余的力X1到Xn?？梢钥紤]類似的方法計(jì)算響應(yīng)的靜不定結(jié)構(gòu)的未知位移量和方程求解的未知數(shù)是使用基于靜態(tài)條件下（平衡條件）。(1)For a given structure and loading,consider the joints to be fully fixed against rotation（1）對于一個給定的結(jié)構(gòu)和加載，考慮關(guān)節(jié)得到充分固定在旋轉(zhuǎn)(2)Calculate the moments in each member of the structure due to the given loads,assuming full fixity at moments are called fixedend moments.（2）計(jì)算結(jié)構(gòu)的每一成員由于負(fù)載的時刻，假設(shè)固定節(jié)點(diǎn)。(5) Generate an equation of moment equilibrium at each joint.（5）產(chǎn)生在各關(guān)節(jié)的力矩平衡方程。Force method can solve all statically indeterminate structures. putational plexity prohibitive for structures with more than three unknown forces.力的方法可以解決所有的靜不定結(jié)構(gòu)，計(jì)算的復(fù)雜性，高昂的結(jié)構(gòu)與三多個未知的力量。這基本上是一個迭代過程（迭代的）。A certain fraction of these distributed moments are carried over to the far ends of members. The released joint is again restrained temporarily before proceeding to the next joint. The same set of operations are carried out at each joint till all the joints are pleted. This pletes one cycle of operations. The process is repeated a number of times or cycles till the values obtained are within the desired accuracy.一定比例的這些分布的矩進(jìn)行了構(gòu)件的遠(yuǎn)端。這個過程是重復(fù)的次數(shù)或周期直到得到的值是在所需的精度。對一個單位在每個旋轉(zhuǎn)力矩會員在關(guān)節(jié)是其剛度ki＝（4ei／L）——（），稱為關(guān)節(jié)僵硬。該方案是有效的， / 12 clockwsie時刻本聯(lián)合建造。 Dynamics 結(jié)構(gòu)動力學(xué)。如果質(zhì)量，m，是假設(shè)集中在梁，結(jié)構(gòu)成為一個單自由度（SDOF）系統(tǒng)的運(yùn)動方程可系統(tǒng)。這種運(yùn)動，這是所謂的強(qiáng)迫振動，被表示為特定的解決方案描述（）。When the force is applied at a frequ