In structures consisting of a frame and thin panels such as aircraft, each of the parts is produced with dimensional tolerances. Naturally, there are gaps between the parts when assembled. In the actual work process, the gaps are measured using temporarily assembled parts and based on the results, shims are produced to fill these gaps. It therefore takes a tremendous amount of time until all the shims with proper thickness distribution are prepared. Mitsubishi Heavy Industries, Ltd. (MHI) constructed an FEM model of the actual contours of the parts using three-dimensional (3D) surface measurement results and established a method to estimate the gaps found in the temporarily assembled parts by numerical simulation. The verification results show good agreement between the simulated gaps and those measured at the time of temporary assembly. This enables shims to be produced based on the estimation results by simulation instead of measurement, thereby shortening the time required for shim procurement.
