Force Measurement Techniques

The interaction between two bodies or components that can be tensile (pull) or compressive (push).

A method of force measurement that directly compares the unknown force with a known gravitational force on a standard mass.

A method of force measurement that determines force indirectly by measuring the effect of the force on a body, such as acceleration.

A type of balance with equal arms, where the unknown force is balanced by a known mass on the other arm.

A type of balance with unequal arms, where the unknown force is determined by the position of a known mass on an arm with varying lengths.

A device for measuring force that utilizes an elastic ring of known diameter with a measuring device at its center.

The proving ring is designed to be made of a durable steel alloy for strength and accuracy in measuring forces.

Proving rings are manufactured according to design specifications laid out by the National Bureau of Standards (NBS), ensuring quality and consistency in measurement.

A device used to calibrate tensile testing machines, measuring force applied by detecting the resulting displacement or deflection using a precision micrometer or LVDT.

The change in diameter of a proving ring when force is applied, measured by LVDT or micrometer. This change is related to the applied force.

A type of sensor that converts displacement into a proportional voltage signal, commonly used with proving rings to measure deflection.

The force applied to a proving ring, usually measured in Newtons (N).

The bending moment generated by the applied force on a proving ring. This moment is a measure of the force's tendency to cause bending.

The radius of the proving ring, a crucial factor in calculating the applied force.

The ability of a material to resist deformation under stress. It's used in proving ring calculations to determine the force from the measured deflection.

The moment of inertia of the proving ring about its centroidal axis. It represents how the ring's mass is distributed and affects how it resists bending.

The outer diameter of the proving ring, used in the calculation of the applied force.

The amount of deformation of the proving ring under a specific load. It's a key parameter in determining the force applied.

The fractional change in length of a material when subjected to a force.

A device that measures tiny changes in dimensions of structures due to applied forces.

A type of strain gauge that uses a material whose electrical resistance changes proportionally to the amount of strain applied.

A device that converts force or weight into an electrical signal.

A type of load cell that operates using the principle of changing electrical resistance caused by strain.

A type of load cell where its electrical capacitance changes based on the applied force.

A type of load cell that uses inductance changes to measure force. Inductance is a measure of a coil's ability to store energy in a magnetic field.

A type of load cell that uses a linear variable differential transformer (LVDT) to measure force.

A Wheatstone bridge is an electrical circuit commonly used in load cells to measure changes in resistance caused by applied force. It's designed to be sensitive to even small variations in resistance and minimize the impact of temperature fluctuations.

When the ratio of resistances R2 to R1 equals the ratio of R3 to Rx, the Wheatstone bridge is balanced. Any slight change in Rx disrupts this balance, allowing for accurate measurement of the change.

Load cells are devices used to measure force by converting it into an electrical signal. This signal is generated by a change in resistance in a strain gauge within the load cell.

Strain gauges are small, sensitive devices that measure changes in length of a material due to applied stress. They are implemented in load cells to detect even minor forces.

The output voltage from a Wheatstone bridge is usually very small, often in millivolts. To read this signal, it's amplified by an instrumentation amplifier. This amplifier provides a low-noise, high-quality amplification for accurate measurement.

A material's resistance change per unit of strain. Higher gauge factor means greater sensitivity to force.

The relationship between an object's resistance and its length: resistance increases with length.

The change in resistance of a strain gauge under tension or compression. Tension increases resistance, compression decreases.

Measures weight by sensing pressure change in a fluid. Safe for hazardous areas due to lack of electrical components.

Uses multiple chambers to improve accuracy compared to hydraulic ones. Ideal for smaller weights where cleanliness and safety are important.

A material's ability to conduct electricity. Conductors have low resistivity, insulators have high resistivity.

The change in resistance of a strain gauge due to strain is caused by two main factors: change in dimension (dominant in metals) and change in resistivity (dominant in semiconductors).

Hydraulic load cells are often used in hazardous areas due to their lack of electrical components. Pneumatic load cells are often preferred in applications where cleanliness is important.