HBM-M-Rosette

Supported Applications

The Omega HBM M Series consists of encapsulated foil strain gages designed for high resistance to alternating loads and operation at elevated temperatures up to 300°C (572°F). These sensors are suitable for testing high-strength materials, including fiber composites. The series supports various measurement geometries required for specific stress states: linear strain in one direction; tension and compression via T rosettes with grids offset by 90°; shear stresses using V-shaped gages arranged at ±45° to the axis; and biaxial stress states with unknown principal stress directions using rectangular or stacked rosette configurations.

Operating Conditions & Performance

The HBM M Series operates within a temperature range of -200 to 300°C (-328 to 662°F). The sensors feature a CrNi (nickel-chromium) alloy foil grid with an approximate gage factor of 2.2, specified on each package. Resistance tolerance is ±0.3%, while gage factor tolerance varies by size: ±1.5% for grid lengths less than 3 mm and ±0.7% for grid lengths greater than or equal to 3 mm.

Performance limits include a maximum positive elongation of 10,000 μm (1%) and a negative direction limit of 15,000 μm (-1.5%). Fatigue life data indicates performance up to 10⁷ cycles at 2000 μm/m, 10⁶ cycles at 2200 μm/m, and 10⁴ cycles at 3100 μm/m when tested to failure.

Configuration Options

The series is available in multiple geometries (LM1, TM1, TM9, XM4, RM8, RM9) with measuring grid lengths of 1.5 mm (0.06"), 3 mm (0.12"), and 6 mm (0.24"). Nominal resistance options are 350 Ω or 1000 Ω.

Key construction features include:

• Carrier Material: Glass fiber reinforced phenolic, with a thickness of 35 ±10 μm.
• Encapsulation: Polyimide film, 25 ±5 μm thick.
• Electrical Connection: Solder pads with strain relief.

The series supports specific bonding materials: Z70 (rapid adhesive) or EP310S (high temperature two-component epoxy resin). Accessories include 1-BCY01 accelerator for the rapid adhesive and cleaning solvents such as 1-RMS1 or its spray version, 1-RMS1-SPRAY.

Maximum permitted effective excitation voltage varies by model geometry and grid length, ranging from 5.3 V to 22 V depending on the specific configuration (specified per model).

Key Product Differences

The HBM M Series distinguishes between linear gages and rosette configurations based on measurement requirements:

• LM1: Linear strain gage with one measurement grid.
• TM1 & TM9: T rosettes (single or stacked) measuring tension and compression with grids offset by 90°.
• XM4: V-shaped strain gage for shear stress determination.
• RM8 & RM9: Rectangular or stacked rosette configurations with three measurement grids at 0°, 45°, and 90° for biaxial stress states.

Packaging varies by model: all models are sold in a 5-pack, except the LM1 series which is sold in a 10-pack. Minimum bending radius requirements differ between linear gages (5 mm / 0.20") and stacked rosettes (10 mm / 0.39").