Structural Properties |
 
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Structural Properties |
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Caution is recommended when specifying properties for rigid or very flexible structures. Experience suggests that using elements of arbitrarily large or small stiffness values is not good practice for finite element analysis, and can lead to solution instability in certain circumstances. For example, if you are modelling a perfectly rigid structure, then it would be advisable to specify a bending stiffness of perhaps 1.0E+10Nm2, rather than an excessively large value of perhaps 1.0E+15Nm2. Conversely, if you are modelling a chain which has effective zero structural bending stiffness in reality, then it might be advisable to specify a relatively low (but non-zero) bending stiffness, such as 10Nm2. For example, if you were to specify as zero bending stiffness for a chain, a solution indeterminacy may occur at some point, if the effective tension distribution in the chain does not provide a sufficient geometric contribution to the overall stiffness.
•*GEOMETRIC SETS is used to assign geometric properties to element sets.