C值是如何和预应力的对应关系：
C Value is the force density value, the ratio of the Force and the Length of a element in the final
shape position.
FormFinding a shape where no constraints are used will be processed in a single linear system
of equations where the equilibrium equations on node j in a net of elements with connections ij are :
With :
Nij = Force in the element connecting nodes i - j
Lij = Length of element i-j
The value Nij/Lij non linear in the above equation is replaced by Cij and solved in a single step.
Good starting values for Cij are not difficult to find out when the initial prestress in the
membrane is known.
Generally, we do formfinding many times to agree not only membrane initial prestress values
but even other aspects like geometry , surface curvature etc.
It is easy to understand that higher values of Cij will shorten the element and increase its internal
force while lower values will elongate it and result in lower forces.
C values depends on the units we are using as it is a Force on a Length ratio, so changing
system units generally needs an update of C values too.
In the tutorials C values will be widely used to model fabric structures and to estabilish the range
of pretress.
We must always keep in mind that overall structure stiffness depends on prestress and geometry,
so if under loads our structure undergoes large displacements even with high internal prestress,
geometry should be checked and maybe changed due to bad initial design.作者:
胆小子 时间: 2005-6-12 11:50 标题: 回复： 请问大家一个关于forten的问题
