P_2.2.4 monitoring

Development of a High-precision Contact-free Measuring Plant for a Full-scale Monitoring of Deformations of Wooden Parts Without the Necessity of Artificial Pass Points

For several projects, a simple but highly precise determination of deformation of wooden components under load is a crucial prerequisite. The methods applied so far shall now be replaced by a camera-based procedure. This procedure allows for a full-scale determination (as opposed to point wise measurement) of the deformation. In doing so, it shall not be necessary to place pass points, but rather the natural texture of the wood itself can be used for this purpose.

This approach is also a requirement for a later use as contact-free real time measuring system for the extension measurings of other projects. The fact that the time behaviour can thus also be included in the examinations represents a further advantage. In this way, also the highly important creep effects can be precisely determined – and, in the following, be modelled or considered when optimising an industrial proof-loading plant.

A calibrated multiple camera system can be used for covering a larger area, but also for a precise determination of 3 D co-ordinates in a stereo configuration. This means that thus also the often neglected but highly important deformations in the third dimension for finite element simulations are precisely determinable.

Additionally, a direct coupling of local deformations and various local wood characteristics (early wood, late wood, finger joint area, knot, marginal knot area, ruptures) is possible, and in this way new findings can be obtained.

The principles determined in the context of this project are a prerequisite for implementing innovative measuring and testing concepts in other directly industry-related projects where the results will have an immediate effect on the relevant system design.