本文旨在運用向量式有限元素法分析結構體受火害後溫度升高之行為,並以平面剛架運動分析為例說明其效果。有別於傳統以變分為基礎的有限元素法,向量式有限元素法將連續體近似成質點的組合,質點運動遵循牛頓運動定律。藉由虛擬逆向轉動分離剛體運動,並搭配變形座標系統定義變形,進而計算元素的內力以作用於質點之上。因此,向量式有限元素法能夠有效模擬連續體同時具有大的剛體運動和大的幾何變形行為。近來由於高樓結構林立,地震引起之火災頻仍,而鋼結構在高溫環境下其多項材料性質將隨溫度上升而迅速下降,導致結構主體及構件產生破壞及變形,本文主要目的即是希望建立溫度與鋼材性質間之關係,配合向量式有限元素法能有效模擬大變形運動之特性,模擬剛架受火害時之大變形行為及其破壞模式,以期對於高溫下結構各項力學行為有更多了解。
The main purpose of this paper is to simulate structures subjected to elevated temperatures for the vector form intrinsic finite element method.Motion analysis of planar frame structures were presented to demonstrate the efficiency of thermal effects. The vector form intrinsic finite element (VFIFE) method, in contrast to traditional finite element approaches which is based on the variational principles, the analyzed structure is simulated by a group of particles. To evaluate the internal forces, a set of deformation coordinate system is defined to dissect the rigid body motions and deformations of elements. Thus the VFIFE method can effectively simulate overall dynamic motions, either rigid body motion or deformation of continua.Rencently,the buildings are higher,and the fires occur often due to the earthquakes.Material properties of steel structures will decrease rapidly as the temperature increases. And that causes the damages and deformations of the members and the structure. The purpose of this paper is to set up a relation between the temperature and the steel with VFIFE and as well as working with the character which can effectively simulate large deformations, more over to have more understandings of mechanical properties objected to high temperature.