Accentuating Buckling Deflection by Transformations and Processing of Point Cloud Data

Abstract

This paper examines the transforms used to analyze the deflection of a trapezoidal box steel beam, approximately 22 feet in length, 10 feet wide on the upper plate, and 2 feet wide on the lower plate, fitted with glass-reinforced polymer (GRP) panels and tested for buckling. The GRP panels were approximately 3 feet by 4 feet and were positioned along the angled web portions of the beam. The deflections were measured with a coherent laser radar (CLR) system. Measuring the beam at no-load position and measuring at the load position causes a transform challenge. Points measured in the no-load position will move in three dimensions when the loading conditions are applied. The points measured from tooling balls, which were the 18 The Journal of the CMSC/Autumn 2008 precision survey features (PSF) on the beam, can show the x, y, and z movement relative from fixed references, which were the control network monuments (CNM) on the floor. Points on a flat surface can only show movement perpendicular to the surface. This is the majority of the points in the scan of the hybrid panels. Making a transform for these surface points would allow the points from the no-load scan to be correlated more closely to the points from the load scan. This transform would need to include movement from the different deflections of the beam and panels. The deflection of the beam and panels include bending-moment deflection, shear deflection, and buckling deflection. The bending-moment deflection includes co