A FE model updating method for the simulation of the assembly process of large and lightweight aeronautical structures

• We propose a model updating process to improve the quality of a finite element model (mass and stiffness parameters).
• The method is applied to highly flexible structures.
• A measurement technology used to acquire the experimental data in the absence of any information on the actual weightless and load-free structure is proposed.
• The updating method is based on the concept of error in the constitutive relation.
• The method is illustrated and validated on two examples.

In the context of the assembly of large aeronautical structures, the flexibility of the parts often leads to the nonconformity of the assembly or, at least, requires additional time-consuming operations. In order to deal with this problem, one must take this flexibility into account during the tolerancing process.Investigations of a non-rigid-body tolerancing process have shown that a robust model is necessary in order to achieve satisfactory predictability. It was also found that the finite element model used, based on a simplified geometry, was not accurate enough. The approach proposed in this paper to obtain an accurate tolerancing process consists in updating the stiffness and mass properties of the FE model based on measurements taken on the assembly line during the assembly process. The objective is to take these measurements using only tools which are available on the chain (such as manipulation or control tools). This implies that only static strength and displacement information can be used. This is achieved through a clever measurement methodology and a model updating method based on the constitutive relation error.