01365792

Component

Measurements of thickness using acoustic methods such as ultrasonic pulse-echo or impact-echo become relevant whenever components are accessible from only one side and the design thickness needs to be verified or the geometry of structures need to be determined. While thickness measurements with acoustic non-destructive testing (NDT) methods are relatively easy and straightforward to conduct on test objects with simple geometries and wide dimensions, they can become quite challenging when the geometry of the test object is more complex or when the dimensions of the test object are rather compact. In such cases, geometry effects, i.e. misleading additional reflections at the geometrical boundaries of the structure other than the intended backwall reflection, can severely interfere with the actual measurement, which applies especially for impact-echo. Measurements have been performed on test blocks with different geometries using an automated test frame, thus providing dense scan grids and therefore good statistical significance. 2D and 3D imaging techniques are applied to the data. In particular, a combined data acquisition and real-time imaging software is presented, which integrates the measurement data into pictures showing test object, thus enhancing the interpretation of the results. Inverse thickness measurements, i.e. measurements where the thickness is known and the velocity is being determined in the test, reveal the elastic material properties, especially when longitudinal and shear wave measurements are combined.

This paper was sponsored by TRB committee AFF40 Field Testing and Nondestructive Evaluation (NDE) of Transportation Structures

01362476

12-4732

English

16p

2012

Transportation Research Board 91st Annual Meeting

Digital/other

Figures; Photos; References

Acoustic detectors; Concrete structures; Measurement; Thickness; Validation

Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls

Transportation Research Board Annual Meeting 2012 Paper #12-4732

TRIS, TRB

Feb 8 2012 5:26PM