From Event: SPIE Smart Structures + Nondestructive Evaluation, 2019
Knowing the grain angle of structural wood members relative to the direction of loading is important in estimating their mechanical performance. The strength of a structural wood member can vary greatly depending on the orientation of grain, making the understanding of grain angle an essential requirement for machine grading and for structural analysis. Condition assessment of structural wood members using non-destructive evaluation (NDE) techniques (e.g., microwave/radar, ultrasonic, stress wave, and X-ray) is a major approach for existing wood structures. Among existing NDE techniques, synthetic aperture radar (SAR) imaging offers technical advantages include remote sensing and subsurface sensing. The objective of this paper is to use SAR imaging to quantify the change in grain direction of various size wood dowels relative to the imaging radar. Two wood specimens were produced each 14 in. long with diameters of 1.25 in. and 1.5 in. Each wood specimen was placed vertically inside an anechoic chamber and imaged at different orientations using a 10 GHz SAR system. It was found that the integrated SAR amplitude and amplitude distribution were affected by the grain orientation of the wood specimens. Further analysis was conducted by estimating the area of contour slices of the SAR images taken in the amplitude direction and were used to confirm the findings.
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Christopher M. Ingemi and Tzuyang Yu, "Detection of grain angle in wood specimens using synthetic aperture radar imaging," Proc. SPIE 10971, Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, Civil Infrastructure, and Transportation XIII, 109710U (Presented at SPIE Smart Structures + Nondestructive Evaluation: March 06, 2019; Published: 1 April 2019); https://doi.org/10.1117/12.2513972.