One of the challenges that currently exists for the design of large aircraft structures under natural-laminar-flow (NLF) regime is the extremely high requirements that must be achieved in terms of tolerances with the aim of ensuring that the flow will be sufficiently stable. In systems composed of many parts (such as the Smart Fixed Wing Aircraft torsion box object of study), the assembly processes acquire a special relevance, taking into account that, depending on how they are executed, the tolerances of each part might accumulate and generate deviations much larger than those of the parts taken individually.

The objective of the present project was the development of a numerical methodology for the analysis of the assembly tolerances of aircraft components designed to operate under natural laminar flow (NLF). The methodology allowed determining the maximum acceptable components deviations to obtain assemblies within the specified tolerances, evaluating the influence of the joining techniques and the jigs, and determining the best assembly strategy or bolting sequence. For that, the proposed approach integrated tolerance accumulation techniques and mechanical/structural tools in order to consider in the analysis the parts compliance and other possible relevant effects associated with the joints.