Numerical analysis using the Finite Element (FEM-FEA) method
Using this technology, we can assess the behaviour of our structures and vehicles from the earliest stages of the design, i.e., even before the product is made! In fact, the finite element method makes it possible to evaluate the strength of materials, deformation and the displacement field of structures of any shape and complexity, with exceptionally accurate results. All this results in designs that emphasize safety and ensure long product life, especially those designed for special uses, such as our OB Vans.
We have finite element analysis software with extremely high capabilities:
Linear Static Analysis (LS): this allows us to quickly evaluate the resistance of structures in the linear elastic range.
Non-Linear Static (NLS) and instability analysis: when the linear range is not applicable, it is possible to apply geometric (large displacement) and material (curves of customized materials) non-linearity, introducing plastic and viscoplastic behaviours, etc., if necessary.
Frequency Analyses: these allow the evaluation of the natural frequencies of the structures (modal analysis) in order to evaluate dynamic behaviour during the operation of the vehicle, as well as to verify that the model is coherently and correctly connected. Moreover, using harmonic analysis, it is possible to evaluate the actual response of a model, starting from the periodic input, impulsive and other types of forces.
Impact tests: When static analyses are not sufficient, we can predict the behaviour of models in an impact (crash testing) or fall, using a powerful explicit solver.
Fatigue Analysis: developed from the theories of Goodman, the FEM model for fatigue life prediction allows predicting how long a component subjected to a cyclic loading will last.
Pressure Vessel Analysis: for checking hydraulic cylinders, but also fuel cylinders and tanks.
Thermal Analysis: to display the distribution of heat on surfaces and the effects of temperature on materials and, thus, the strength of structures.
Finite Element Classes at our disposal:
Truss: In the case of trusses, where it is plausible that tie rods/struts could be subject to just axial load, the simplest and fastest solution is a "truss" element.
Beam: A generic beam element, subject to normal stress, shear and moment. This allows fast solutions for all the structures we produce.
Shell: 2D elements, suitable for modelling sheet and tubular metal. This allows the optimum solution in terms of the quality/time of the analysis.
Brick: The solid 3D element used for analyzing structures of any shape.
Examples of the application of FEM in our company:
Overturning Analysis: school bus regulations require overturning tests for several types of vehicles. This test is normally destructive but we regularly carry it out with an FEM calculation method that is amply validated by experimental tests filed with the Ministry of Transport. This is an example of how we can evaluate the results even before building the vehicle!
Resistance analyses: in general, the structural metalwork produced in-house, such as for vehicle compartments, or the extension systems of our OB Vans, is evaluated using the methods described above to verify tensions, deformations and displacements. If necessary, this analysis is even applied in the construction of the RACKS.