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LOAD PINS
INSTRUMENTS
BOLTS & STUDS
TENSION LINKS
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Fatigue Rated Universal Flat Load Cells
The Fatigue Rated Flat Load Cells are similar to the Universal Flat Load Cell models
and are designed for fatigue measurement/control applications in both tension, compression and/or tension/compression
directions. The load cells possess very low deflection, high natural frequencies, and a
one billion cycles fatigue rating!
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The structure of the load cell is simple and compact, consisting
of an inner loading hub and an outer supporting flange bridged smoothly by a uniformly
continuous solid shear web, avoiding structural stress risers. Strainsert gages are installed and sealed inside small gage
holes along the neutral axis of the web. Low deflection and high natural frequency of the load cells are obtained, along
with high resistance to extraneous forces. Mechanical and dynamic properties of
load cells are fully tabulated.
Long fatigue life (one billion cycles) and stability of the Flat Load Cell is mainly
due to low strain levels the shear gages are subjected to ±500µe FS for completely
reversed "C/R" rating and 750µe FS for unidirectional "U/D" rating at ±2-mV/V and 3-mV/V
nominal output signal levels respectively.
Linearity and symmetry of output signal in tension and compression are obtained by equal
straining of all shear gages in the bridge circuit of the Flat Load Cell.
Barometric or hydrostatic pressures, or vacuum environment do not produce erroneous output signals
in Flat Load Cells.
Allowable loads that fatigue rated Universal flat load cells will withstand for one billion cycles
without failure are tabulated under Uni-directional (U/D) and Completely Reversed (C/R) load headings.
In specifications the relation is stated as (U/D) = 150%(C/R).
Allowable intermediate loads between uni-directional (U/D) and Completely Reversed (C/R) loads
can be read off the limit chart (see limit chart below), where (C/R) FS Fatigue Load Rating is defined
as ±100% at one billion cycles. Peak tension and peak compression, as well as mean tension
and mean compression, loads are also given in % (C/R) FS.
Overload allowance in Fatigue Rated Flat Load Cells can only be made at the expense of
fatigue life. However, when the required service life of a load cell is less than one billion cycles,
advantage may be taken of the reduced fatigue life and the cell may be rated at higher peak loads, per overload factors
given in the below specifcations. Once this overload is applied, however, even for a few cycles, fatigue life
of the cell must remain at the reduced value. Thus peak load ratings corresponding to one billion cycles
should not be exceeded if long fatigue life is an important consideration for the load cell. The load
capacity and corresponding life of a Fatigue Rated Load Cell is stated below. In the following example consider
the below case:
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FFL (180/±120) U (C) - (3/±2) SPKT
Where Uni-directional (U/D) Rating is 180,000 lbs., and completely reversed (C/R) Rating is ±120,000 lbs.
From limit chart intermediate ratings are available. Say at +50% (+60,000 lb) Mean Tension Load
Allowable peak tension load is +133% of 120,000 lbs. = +159,600 lbs.
Allowable peak compression load is -33% of 120,000 lbs. = -39,600 lbs.
All at one billion load cycle fatigue life. If, on the other hand, required service life
of the load is only one million load cycles, then, from overload allowance chart all load ratings
can be increased by an overload factor of 1.10, thus:
(U/D) = 1.10 X 180,000 = 198,000 lbs.
(C/R) = 1.10 X (±120,000) = ±132,000 lbs.
At +50% (+60,000lbs) Mean Tension Load, the allowable peak tension = 1.10 X 159,600 = +175,560 lbs.
The allowable peak compression = 1.10 X (-39,600) = -43,560 lbs., All at one million load cycle fatigue life
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| Some Features Include: |
| · Precison Load Sensing |
· Easy Installation |
| · Rugged |
· Direct Force Measurement |
| · Internally Sealed Strain Gages |
· High Natural Frequency |
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 Fatigue Rated Universal Flat Load Cells
Online Catalog |
 Load Cells
CAD Library |
 Specification
Table |
Specification Limit
Chart |
Fatigue Rated Load Cell
Dimension Table |
 Specification Drawing and Order
Information |
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Strainsert - for superior internally gaged force transducers.
Strainsert stands for:
- Product Quality
- Knowledgeable Technical Staff
- Standard and Custom Designs
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- Comprehensive Testing
Contact Strainsert
For information on load pins, force sensing bolts, load cells, tension links or our high quality custom products, Contact Us for further assistance.
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