Patented SG hole drilling rosette accurately determines residual stresses

HBM has launched a patented hole-drilling rosette to increase the accuracy of residual stress measurement by a factor of five. In the hole-drilling method, which is one of the most common methods of determining residual stresses in components, strain gages (SG) determine the deformation – or relaxation strain – around a drill hole while it is being drilled.

Residual stresses are mechanical stresses that exist in a material without external forces or moments acting on the component. They can occur in metallic work pieces during production caused by, for example, uneven cooling during casting or by rolling. Residual stresses affect the component in the same way as load-induced stresses, and can reduce its load-carrying capacity.

It is essential for manufacturers to determine the residual stresses in any component so that they can be assured of its operational reliability.

HBM’s new RY61M SG hole-drilling rosette has a patented structure that utilizes six measuring grids instead of the customary three to determine the eccentricity of the hole which is a potential source of error. The hole-drilling rosette measuring grids are arranged around the drill hole, with each of the opposite SG pairs being interconnected so that their signals are averaged.

The measurement error resulting from drill-hole eccentricity is reduced by a factor of five because HBM uses six measuring grids. The RY61M SG is easily connected as the measuring grids are already connected on the carrier foil, or on a small PCB (printed circuit board).


About HBM:
HBM (www.hbm.com) is a globally operating company specializing in test and measurement. HBM provides complete measurement solutions - from sensor to software - based on high quality products as strain gages, load cells, tranducers, signal conditioning and data acquisition electronics and software.

With development and manufacturing operations in Europe, America and Asia, HBM provides measurement solutions to a wide variety of companies in the automotive, aerospace, marine, rail transport, medical equipment, packaging, appliance, automation, and scale industries.

With a 50 year history of quality and precision products, the HBM name has become synonymous with "Measurement with Confidence.

For further information please contact:

1 Churchill Court, 58 Station Road, North Harrow, Middlesex, HA2 7SA UK
Tel: +44(0) 20 8515 6100
Fax: +44(0) 20 8515 6149
Web: www.hbm.com

August 2010

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