With geometry, supports and loads defined, the structural model is ready for processing. The “Analyze”-component computes the mechanical response for each load case and adds this information to the model.
The algorithm behind the “Analyze”-component neglects the change of length in axial or in-plane direction which accompanies lateral deformations. This is justified in case of displacements which are small with respect to the dimensions of a beam of shell. For dealing with situations where this condition does not hold, geometric non-linear calculations need to be used (see sections 3.5.3 and 3.5.4).
In case of the presence of second order normal forces (
, see below) their influence on structural stiffness is taken into account. Those
-forces do not get updated by the “Analyze”-component. Use the “AnalyzeThII” for that.
Fig. 3.6.1: Deflection of simply supported beam under single load in mid-span and axial, compressive load
Fig. 3.6.1 shows a deflected beam with two load-cases. An axial load acts in load-case zero, a transverse load in mid-span in load-case one.
The analysis component not only computes the model deflections but also outputs the maximum nodal displacement (in centimeter), the maximum total force of gravity (in kilo Newton, if gravity is set) and the structure's internal deformation energy for each load case - section 3.6.2 contains details on work and energy. These values can be used to rank structures in the course of a structural optimization procedure: the more efficient a structure, the smaller the maximum deflection, the amount of material used and the value of the internal elastic energy. Real structures are designed in such a way that their deflection does not impair their usability. See section A.2.3 for further details. Maximum deflection and elastic energy both provide a benchmark for structural stiffness, yet from different points of view: The value of elastic energy allows to judge a structure as a whole; The maximum displacement returns a local peak value.