Hand calculations form the basis of almost all engineering projects. They have many roles and are vital in a wide range of technical aspects – from general guidance for mechanical and structural design concepts to the direct validation of FE analysis models.

First principles calculations are performed to allow key variables to be manipulated such that the initial outline concepts can be determined, for example in the design and specification of

- structural frameworks
- power transmission components
- storage vessels
- prime movers, eg. motors, hydraulics, ..
- outline chassis behaviour

Certain projects require the use of static equations for stress-based design such as simple beam theory, torsion, impact and pressure vessel problems. While other projects with structures experiencing cyclic loading shall utilise a range of stress and strain-based fatigue models to evaluate their design and predict their service life.

Frequently, the loads experienced on structures are dynamic (external excitation, shock loading, etc..), so dynamic theory hand calculations are used to estimate dynamic behaviour, such as natural frequencies or basic responses (e.g. harmonic in vibration systems). Such hand calculations are frequently the first steps undertaken to avoiding resonance in dynamic structures.

Hand calculations also have an important link with FEA simulations. While determination of loads, restraints and material properties often take the form of hand calculations, the verification and validation of FEA results with an independent set of hand calculations is critical in order to provide confidence in the analysis results.

The application of engineering theory with hand calculations form the basis of many aspects of our work at Aecentus.