Measurement of Weld-Induced Deformations in Three-Dimensional Structures Based on Photogrammetry Technique

摘要

This paper presents an approach for measuring weld-induced initial distortions in plated structures, allowing also for the possibility for transferring that information directly to finite element models. Photogrammetry, which employs a three-dimensional measurement technique and central projection imaging as a fundamental mathematical model, has been used to generate the displacement field from sets of digital images of box girders. Three-dimensional deformation models of box girders were obtained before and after a buckling collapse test. A comparison between the photogrammet-ric result and Smith's initial imperfection classifications has been performed. A new equation to predict the initial imperfections of very-thin-walled structures has been developed. It is demonstrated that the output of the photogrammetry analysis can be used as a direct input to a finite element model of the deformed structure. The procedure was validated against direct measurements of the deflections, and statistical analyses of the error between measurements and photogrammetric evaluations are presented.