HBM-M-Linear

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: linear strain in one direction (LM1), tension and compression via T rosettes (TM1, TM9), shear stress determination using V-shaped grids (XM4), and biaxial stress state analysis with unknown principal stress directions using rectangular or stacked rosettes (RM8, RM9).

Operating Conditions & Performance

The HBM M Series operates within a temperature range of -200 to 300°C (-328 to 662°F). The grid foil is constructed from CrNi alloy with a thickness of 5 μm, mounted on a glass fiber reinforced phenolic carrier (35 ±10 μm thick) and encapsulated in polyimide film (25 ±5 μm thick). Nominal resistance values are available at 350 Ω or 1000 Ω. The series supports maximum elongation of 10,000 μm/m (1%) in the positive direction and -15,000 μm/m (-1.5%) in the negative direction. Fatigue life is documented as 10⁷ cycles at 2000 μm/m, 10⁶ cycles at 2200 μm/m, and 10⁴ cycles at 3100 μm/m.

Performance specifications include a gage factor of approximately 2.2 (specified on each package) with tolerances of ±1.5% for grid lengths <3 mm and ±0.7% for grid lengths ≥3 mm. Resistance tolerance is ±0.3%. The temperature response on ferrite steel is 10.8 ppm/K (6.0 ppm/°F). Minimum bending radius requirements are 5 mm (0.20") for linear gages and 10 mm (0.39") for stacked rosettes.

Configuration Options

The series offers configurable measuring grid lengths of 1.5 mm (0.06"), 3 mm (0.12"), or 6 mm (0.24"). Electrical connections are provided via solder pads with strain relief. Maximum permitted effective excitation voltage varies by model, ranging from 7 V to 22 V depending on geometry and grid length.

Available bonding materials include:

• 1-Z70: Rapid adhesive; single component cold curing cyanacrylate.
• 1-EP310S: High temperature adhesive; two-component epoxy resin.
• 1-BCY01: Accelerator for Z70 rapid adhesive (epoxy resin).

Cleaning and preparation accessories include:

• 1-RMS1: Cleaning solvent; environmentally friendly mixture of isopropanol and acetone.
• 1-RMS1-SPRAY: Spray version for application on vertical surfaces or overhead work.

Key Product Differences

The HBM M Series distinguishes variants by geometry, grid length, and resistance. The LM1 model is a linear strain gage with one measurement grid. TM1 models are T rosettes with two grids offset by 90°, while TM9 models are stacked T rosettes for the same purpose. XM4 models feature V-shaped grids arranged at ±45° to determine shear stresses. RM8 and RM9 models provide rectangular or stacked configurations with three measurement grids at 0°/45°/90° for biaxial stress states.

Model numbering follows the pattern 1--/GE. For example, model 1-LM11-1.5/350GE denotes a linear gage with a 1.5 mm grid and 350 Ω resistance. Packaging quantities differ by geometry: LM1 models are sold in 10-packs, while all other geometries (TM1, TM9, XM4, RM8, RM9) are sold in 5-packs.