Study On Truss Element Of Finite Element Method And Its Application

In the practice of engineering, finite element method is generally used to analyze the mechanics behavior of important structures or structures under complicated loads. Finite element method is one kind of calculating method that based on computer. It has simple principle and the characteristic of wide suitability. It is commonly used to analyze mechanics problems of continuous medium. When finite element method is used to analyze mechanics behavior of reinforced concrete structure, suitable crack model should be used to imitate concrete cracks and analyze the whole and local stress, strain, deformation, etc. of the structure before and after it's cracking because the characteristic that concrete can easily be cracked and concrete structures are always on work with cracks. The most commonly used models of crack of concrete structure in finite element method are discrete cracking model and smeared cracking model. However, these two kinds of crack models both have its deadly weaknesses, the former needs to redistrict the unit again and again, the latter can only analyze structures as whole and can't be used to analyze local mechanic behavior of the structure deeply near cracks. As to finite element method itself, though its principle is simple, the calculating process is complicated and the shape function is difficult to construct.Just because of such an engineering using background, a new kind of truss element model is put out at home. The new kind of model has combined the advantages of finite element method and infinite small element method; it also has combined the advantages of constant strain element and high times element. This method has reduced the degree of freedom of the original microelement by using eight poles in four directions, which can only be tensed or compressed along their axis, to analyze the mechanic behavior of the microelement under biaxial or tri-axial stresses. The truss element method does not need to construct shape function; the calculating precision is only correlated with how fine the structure been divided. To truss element, poles on each direction has different stress and strain states. This character makes truss element better than constant strain element. As using truss element method, structures are divided into many poles, which can only be tensed or crushed, contacting each other on two extreme points; interactions between units and units become more obvious; if one of this poles goes cracked or crushed, how much the mechanics behavior of any other pole will be influenced can easily be tracked. This characteristic makes truss element more suitable to imitate concrete structures' performance of crack or crush.Though truss element method has a great deal of advantages, it is steal unknown to people, studies on it just take one step, their steal have many problems need to reach. These...