After determining the unknown displacements, the other forces are calculated satisfying the compatibility conditions and force displacement relations. Primary unknowns are the displacements and initially force -displacement relations are computed and subsequently equations are written satisfying the equilibrium conditions of the structure in this method. Once the redundant forces are calculated, the remaining reactions are evaluated by equations of equilibrium. Solving these equations, redundant forces are calculated. Primary unknown are forces in the members, and compatibility equations are written for displacement and rotations (which are calculated by force displacement equations) in this method. In case a refresher is needed on internal and external indeterminacy: external indeterminacy means you can't find the support reactions using only the equilibrium equations internal indeterminacy means you can't solve for the members' internal forces using only equilibrium equations.Correct Answer - Option 2 : equilibrium of forces Example 7.3.1 For the statically determinate truss in Figure 7.3.1. As an example, consider a planar truss, as shown in Figure 6.1(a).
This post introduces you to this idea by doing the former. It can be as simple as analysing a beam using virtual work or complex like deriving the finite-element method. I honestly don't remember how to use the force method, so I'd certainly use the displacement method. The force method of analyzing a structure begins with the use of statics to. The force method of structural analysis, in which the member forces are used as. I n certain structural analysis applications, we can analyse structures in terms of work-energy principles. This is why almost all structural analysis software uses the displacement method.įor structures which are only slightly externally indeterminate (by one or two degrees of freedom) and which aren't very complex (or which can be decomposed into simple sub-structures), the force method might be useful if you're doing things by hand.įor internally indeterminate structures. Obviously, indeterminate structures will have more complicated solutions, but the basic working is all the same. All structural analyses are based on satisfying one of the fundamental. The displacement method is useful in that it is agnostic to such things, statically determinate and indeterminate structures are identical, as far as the method is concerned. matrix analysis this is not regarded as a hand-method of analysis. Depends on your definition of "better" and on the specific truss being analyzed.
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