Considerations for the Strain Gage Series selected must include that of specific test profiles, such as strain type (static, dynamic, etc.), operating temperature, measurements duration, importance of (absolute) precision, and tests requiring cyclic endurance.
The recommended gage series for certain test “profiles,” or groupings of test requirements, are listed in the second table below, which is organized by the following criteria:
The opening table (please see below) contains brief descriptions of all general-purpose strain gage measurement series, covering the alloy and backing combination as well as the main construction elements in each case.
or most traditional applications, this table provides the basic means for preliminary gage series selection. It also provides adhesive suggestions, because the adhesive in a strain gage installation becomes part of the gage system, affecting performance of corresponding gauge.
This selection table is used in conjunction with HBM Strain Gauges to arrive at the entire gage selection, which is augmented by the information in the first table. The steps to accomplish this can be found HERE.
| Test or application type |
Temperature Range of Operation |
Gage Interval in Hours |
Precision Required ** |
Cyclic Durability Required | Standard Selection | ||
| Highest Strain | Number Of Phases | Gage Run | M-Bond Adhesive | ||||
|
Stress Analysis (General Static or Static-Dynamic)* |
–50° to +150°F (–45° to +65°C) |
<104 | Modest | ±1300 | <106 | C2A, L2A, W2A, CEA, EA | 200 or AE-10 |
| <104 | Modest | ±1300 | <106 | C2A, L2A, W2A, CEA, EA | AE-10 or AE-15 | ||
| <104 | Very High | ±1600 | <106 | WA, SA | AE-15 or 610 | ||
| <104 | High | ±2000 | <106 | WK, SK | AE-15 or 610 | ||
|
–50° to +400°F (–45° to +205°C) |
<103 | Modest | ±1600 | <106 | WA, SA | 600 or 610 | |
| <103 | High | ±2000 | <106 | WK, SK | 600 or 610 | ||
| –452° to +450°F (–269° to +230°C) | <103 | Modest | ±2000 | >106 | WK, SK | 610 | |
| <600°F (<315°C) | <102 | Modest | ±1800 | <106 | WK | 610 | |
| <700°F (<370°C) | <10 | Modest | ±1500 | <106 | WK | 610 | |
|
Elevated- Elongation (Post- Analysis) |
–50° to +150°F (–45° to +65°C) |
<10 | Modest | ±50 000 | 1 | CEA, EA | AE-10 |
| >103 | Modest | ±100 000 | 1 | EP | AE-15 | ||
| >103 | Modest | ±200 000 | 1 | EP | A-12 | ||
| 0° to +500°F (–20° to +260°C) | <102 | Modest | ±15 000 | 1 | SA, SK, WA, WK | 610 | |
| –452° to +500°F (–269° to +260°C) | <103 | Modest | ±10 000 | 1 | SK, WK | 600 or 610 | |
|
Analysis of Dynamic (Cyclic) Stress |
–100° to +150°F (–75° to +65°C) |
<104 | Modest | ±2000 | 107 | ED | 200 or AE-10 |
| <104 | Modest | ±2400 | 107 | WD | AE-10 or AE-15 | ||
|
–320° to +500°F (–195° to +260°C) |
<104 | Modest | ±2000 | 107 | WD | 600 or 610 | |
| <104 | Modest | ±2300 | 106 | WD | 600 or 610 | ||
|
Gaging of Transducers |
–50° to +150°F (–45° to +65°C) |
<104 | 1 to 5% | ±1300 | <106 | CEA, EA | AE-10 or AE-15 |
| <106 | 1 to 5% | ±1300 | <106 | CEA | AE-15 | ||
| –50° to +200°F (–45° to +95°C) | <104 | Greater than 0.2% | ±1500 | 106 | N2A | 600, 610, or 43B | |
| –50° to +300°F (–45° to +150°C) | <104 | 0.2 to 0.5% | ±1600 | 106 | WA, SA | 610 | |
| –320° to +350°F (–195° to +175°C) | <104 | Greater than 0.5% | ±1800 | 106 | WK. SK | 610 | |
| * T Most testing circumstances that demand some degree of stability under static test settings fall under this category. It may be essential to use half- or full-bridge arrangements with constantan gages for absolute stability during lengthy periods of use and temperatures above +150°F (+65°C). Other than transducer applications where the element is hermetically sealed, protective coatings may have an impact on stability.
** Without considering different characteristics of the actual test program and the instrumentation used, it is inappropriate to evaluate “accuracy” as stated in this table. For stress analysis purposes, “moderate” is defined as 2 to 5%, “high” as 1 to 3%, and “very high” as 1% or better.
|
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The CEA Series is frequently the ideal choice for routine strain-measurement circumstances that do not require extremes in performance or environmental capabilities, as shown in the previous table (and not requiring the very smallest in gage lengths, or specialized grid configurations).
CEA-Series strain gages are polyimide-encapsulated A-alloy gages with big, durable, copper-coated tabs for soldering lead wires to the gage directly (below). Almost any radius can be contoured with these thin, flexible gages. CEA-Series gages excel in terms of overall handling qualities, such as convenience, resistance to damage in handling, and so on.
The C2A Series strain gages have been a popular choice for field applications where time is of the essence.
The C2A Series gages are a laminated polyimide- encapsulated A-alloy gage with 10 feet of pre-attached vinyl cable which helps to save time during the gage installation, whether in the lab or in the field.
The W2A is one of the newer strain gauge products on the market, with a layer of RTV silicone rubber put over the top of a typical CEA Series gage pattern to provide water resistance.
Strain gages are ideal for verifying stress and displacement simulation models. The strain measurements are taken at specific locations and correlated with the simulation results.
Modeling assumptions such as boundary conditions, contacts, and loads may be updated to make the simulation better fit the observed behavior.
Once the model accurately reflects the measurements, more detailed information about the system can be inferred.
In addition, simulations of the modified system can be used to predict behavior with confidence.
SimuTech Group specializes in both strain gage measurement as well as simulation, allowing seamless support when conducting investigations.
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