b'F orce andM ateriaLt estinGt erMinoLoGyTerms DescriptionLoad Load is a common term used in place of a force exerted on a surface or a body, it is often expressed in either N (Newton, 1 kg * m/s2), LBF (pounds force), KGF (kilograms force). On a force measurement machine load is measured with a Load Cell Sensor.Stress Stress is a measurement of force (load) per unit area. It is often denoted by(sigma). To calculate stress you will need to know force and area of the sample being tested. Stress is expressed in either PSI (Pounds per inch2, lbf/(in2 )), KSI (Kilograms per inch2, kg/m2 ), or MPa (Mega Pascal, 1 Pascal = N/m2 ). Strain Strain is the amount of deformation of a sample compared to the samples original size. It is often denoted by(epsilon). Strain values are unit-less (because in the ratio the units cancel themselves out).However, it can be expressed by a percentage or referred to as stains.Elasticity Elasticity is the ability of a material to return to its original shape when a load causing deformation is removed. An Elastic material will obey Hookes Law where Stress is directly proportional to Strain. Springs are supposed to obey Hookes Law.Plasticity Plasticity describes when a material tends to remain deformed even after reducing the Stress that caused the original deformation. A plastic material will retain its shape once the load causing the deformation is removed. Plasticity is closely associated with malleability where a material erminologycan be worked or hammered into a permanent shape.Stiffness Stiffness is the resistance of an elastic material to deformation after an applied load.Elongation Often associated with ductility, Elongation is the increase in gauge length divided by the original gauge length. Elongation is typically expresses as a %.Extension Extension is the measurement of distance, Extension is sometimes called Deflection and is expressed in either; IN (Inch), MM (millimeter), or % (percent elongation). On a force measurement machine extension can be measured with an internal encoder or using an ancillary extensometer.TModulus of Elasticity Also referred to as Youngs Modulus. It is the rate of change of Stress as a function of Strain. It characterizes materials as a measure of their stiffness. It is calculated as the slope of the line before the proportional limit.Proportional Limit The highest Stress at which the curve in a Stress/Strain diagram is a straight line.Axial Load The load applied to the primary axis. Sensors have a live side, e.g. the side where load is to be applied. Incorrect loading WILL result in erroneous readings.Full Scale Deflection The mechanical deflection produced by the load sensor when maximum (full scale) load is applied. All load cells deflect when load is applied. TemperatureLoad cells are affected by temperature which can impact Zero Balance.Compensation Our sensors are temperature compensated. Its good practice to allow the load sensor to warm up (5 minutes) prior to use.Capacity The maximum axial load a load cell sensors is designed to measure within its specification.Span Another term used to express the sensors maximum rated output.Zero or Zero Balance The signal of the load cell when no load is applied.No Load The condition of the load cell, when in its correct orientation, and with no load applied and no fixtures attached.Mode Starrett load cells will operate in Tension and Compression modes.None-linearity The algebraic difference between output at a specified load and the corresponding point along a straight line drawn between minimum load and maximum load. Normally expressed as %FS (Full Scale).Hysteresis The algebraic difference between output at a given load descending from maximum load and output at the same load ascending from minimum load.TEDS Short for Transducer Electronic Data Sheet, TEDS chips allow Starrett load cells to be self-identifying, this Plug & Play ability minimizes system setup time and stores sensor calibration dataNIST Certification National Institute of Standards and Technology. Starrett load cells are supplied with a Certificate of Calibration traceable to NIST.ASTM E4 AKA: American Society for Testing and Materials. E4 isthe Standard Practices for Force Verification of Testing Machines.ASTM E83 is the Standard Practice for Verification and Classification of Extensometer Systems. Normally, ASTM E4 is required for a Material Test System, but NOT necessary for a Force Measurement Test System.starrett.com 187'