New procedure for recognising minimal defects in wood panels awarded for scientific breakthrough

Reward for his research work: Dr Torben Marhenke received the Wilhelm-Klauditz Award

The Wilhelm-Klauditz Award, a German award that recognises outstanding scientific or application-oriented work in the area of wood research and environmental protection, is given to Dr Torben Marhenke, a researcher from Fagus Grecon, for his development of a new non-destructive test procedure that recognises defects in wood with a diameter starting at 1mm. Fagus Grecon is a Germany-based company, specialised in fire protection systems, measuring equipment and inspection systems for many types of industries, including the wood-based panels industry.

In spite of extensive use of wood materials in construction, engineering knowledge on the measuring-technical determination of mechanical wood parameters has been lacking so far. Where isotropic materials such as metals can make do with two parameters, wood materials require nine of them for clear description of their mechanical material behaviour. The measuring methods developed by Marhenke in the scope of his research will permit non-destructive determination of all nine required parameters and even right in the production process in future.

Increased use of, for example, wood panels in construction makes recognition of even the smallest delaminations essential, as they may grow into cracks or allow moisture to enter the material. The new inspection method makes it possible to utilise the entire application potential of wood materials in construction. Production issues can be recognised early on, and countermeasures can be taken quickly, reducing rejects and warranting the corresponding qualities in spite of growing requirements.

The inspection method by Marhenke is a further development of the air-coupled ultrasound procedure (ACU). Using this procedure does not require any coupling medium between the sonic head and specimen, though use in production usually requires a minimum distance between the sample and the sonic heads in order to avoid contamination of or damage to the sonic heads.

The shaft bend causes the image to blur increasingly as the distance grows, negatively affecting in particular thicker composites, such as wood panels. According to Fagus Grecon, while this procedure used to be able to only recognise defects starting at a size of 25mm x 25mm, the measuring process expansion developed by Marhenke will be able to recognise defects with a diameter from 1mm onwards in the future. In addition to strict error recognition, the procedure can even determine the precise position of the defect, permitting conclusions regarding its cause.