XY and RY Strain Gauges for Determining Residual Stress
HBM offers you strain gauges for analysis of residual stress and for the ring-core method as well as the hole drilling method.
A common feature of both methods is that, after installation of the strain gauge rosettes onto the work piece, the residual stress condition is disturbed by a suitable action. In the case of the ring-core method this is done by cutting a circular groove around the strain gauge rosette. In case of the hole drilling method, a hole is drilled into the center of the rosette.
Following this action, residual stresses cause strains on the surface of the workpiece, which are detected by the strain gauge and then used to calculate the residual stress state. The HBM product line gives you a choice between three different methods for determining residual stress.
Ring-core method: XY51 rosettes (for residual stresses with known principal direction) and RY51 rosettes (for residual stresses with unknown principal direction) are specifically designed for the ring-core method. This method provides high-precision measurements and the residual stresses are represented depending on the drilling depth.
As these strain gauges are covered by a print plate, they can be used on level or slightly curved surfaces only.
- XY51: For residual stresses with known principal direction
- RY51: For residual stresses with unknown principal direction
Hole-drilling method based on the integral method: RY21 and RY61SG rosettes together with the corresponding drilling equipment can be used to determine residual stresses according to the integral method.
The result is the integral average of the residual stresses over the entire drilling depth.
- RY21: Especially easy to handle. Temperature response optimized for steel.
- RY61: Drill hole rosette. Covered by a print plate and can therefore only be used on level or slightly curved surfaces.
Hole drilling method with high-speed drilling: Drill hole rosettes RY61S, RY61R, RY61K, VY61S and RY61M are specially designed for the requirements of high-speed drilling. This method works with a special drilling technique with the cutter operating at a speed of about 350.000 - 400.000 rpm. This prevents new residual stresses from occurring during the machining process. This method produces extremely precise measurement results that make it possible to represent residual stresses depending on drilling depth very precisely.
- RY61M: Patented structure with six measuring grids. The signals of opposite SGs are determined, which reduces measurement errors, depending on possible eccentricity of the drill hole, by a factor of 5.
No additional connection work because the measuring grids have already been wired on the carrier foil.