Damage Assessment of Beam by a Quasi-Static Moving Vehicular Load

This paper presents a new approach of health monitor using the curvature of the influence line. The study included numerical simulation and experimental test of Hbeam to demonstrate the effectiveness of the new approach. The specific work includes: loading test method for moving vehicular to measure displacement influence line of beam structure, obtaining Eigen-damage intrinsic mode function (IMF) of displacement influence line with ensemble empirical mode decomposition (EEMD), processing the second-derivative on displacement influence line to obtain curvature influence line of Eigen-damage IMF, fitting against which through polynomial to obtain quasiundamaged curve, using the product of absolute difference from both curvature influence line and quasi-undamaged curve to identify damage location of beam structures by means of the product of curvature difference map after fitted. Theoretical development and experimental verification are carried out on H-beam in this paper. In the experiment, measures of displacement influence line at middle span (L/2) of the H-beam when moving vehicular pass by. EEMD, curve fitting and calculating curvature of displacement influence line, etc. methods are used to process displacement influence line. The advantages of this experimental method are fast, time-saving, simple equipment set-up, and can avoid the disturbance of surrounding environmental vibration, but also trouble in a shortage of undamaged condition for the structure. ANSYS software in the paper simulates displacement influence line at middle span under loading test for H-beam to understand the change of displacement influence line for damage identification, which is used as a basis of theoretical development. Finally, conduct loading test method for moving vehicular to measure displacement influence line at middle span of H-beam; connecting with EEMD, curve fitting, and calculating the curvature of displacement influence line can effectively and quickly identify damaged location.