这几天看了一篇介绍性论文，对其中的astic redundancy & geometric redundancy相当费解。清高手指点。
文中说，
  Redundancy is more than the statically indeterminacy, 这个可以理解。
  The number of indeterminacy is distributed among all elements in relation the geometry of the structure, the stiffness of the elements and the relatively elongation of each element within the structure. 最后那个the relatively elongation在这里是什么意思？为什么也会影响到 the number of indeterminacy？(The eleastic elongation of each element is influenced by stiffness of the connected elements.)
  然后说到 elastic rudundancy is in terms between o and 1. ( 0 means no forces arise if the length and single element is changed. 1 means changing the length leads to a force depending on the elastic stiffness.)
  下面这段是说的geometric redundacy， 我也没怎么理解。 Cinematic strutures can be stabilised by tension forces. Tension forces built up a resistance if the structure is deformed under load known as geometrical stiffness. The three components of the stabilising tension forces lead to three additional equations for each element in a pretensioned structure an additional geometric redundancy.-----three components 指的是什么？geometric redundancy该怎么理解？
  接下来的那个解释geometric redundancy的也没看懂 The geometric redundancy of 3 says no influence of the geometric stiffness is required; lower than 3 describes the part of the geometric stiffness necessary for stabilisation and higher than 3 menas the element is unstable and needed to be stabilized.
  
  出自今年6月份在巴塞罗亚的Structural membranes 2003 conference的论文集Textile Composites and Inflatable Structures中的 Lightweight structures tendencies and developments (by Rosemarie Wagner)
  

geometric redundancy＝3×n－3×m
  
n是索膜节点总数，m是固定节点个数（按铰接），嘻嘻，猜的，redundancy是结构节点总自由度减去约束后的剩余自由度吧。