Types of Force Measurement Tests 101
There are distinct types of force tests that engineers, product designers, manufacturers, and test labs perform to accurately measure factors that control quality, safety, and reliability.
Testing force helps to qualify how something will react when applying load, either by a normal application or by pulling and pushing it fails. The type of force measurement classifications are compression, fracture, tension, flexure, and shear.
Interface provides a broad range of solutions for static and dynamic force measurement tests including standard and custom transducers, instrumentation, accessories, frames, calibration equipment and other components used for in force testing.
The most common categories of force testing include:
- Tensile testing
- Shear testing
- Compression testing
- Fatigue testing
- Torque testing
- Hardness testing
- Static testing
- Mechanical strength testing
- Material testing
- Proof load testing
- End of line testing
There are variations to each of these test classifications, such as cycle testing is often a subset of fatigue and mechanical strength tests. Hardness testing is frequently referred to as nondestructive testing. Initial R&D tests typically center around choosing materials, strength and durability tests, compression ergonomic and abrasion tests.
Here are the general characterizations of the most popular types of force tests.
Tensile strength is the ability of a metal to withstand a pulling apart tension stress. Performing a tensile test, sometimes referred to as tension testing, applies uniaxial load to a test bar and gradually increasing the load until it breaks. The measurement of the load is against the elongation using an extensometer. The tensile data is analyzed by using a stress-strain curve. Interface load cells are commonly used for various tensile tests when accuracy of measurement matters.
Compression is the result of forces pushing towards each other. The compression test is like the tensile test. Place the object in a testing machine, apply a load and record the deformation. A compressive stress-strain curve is drawn from the data. Interface provides load cells that measure compression-only or tension and compression measurements from the same device.
Torque measurement determines how an object will react when it is turned or twisted. There are two common use cases, fastening tests of objects or by testing rotating parts in an assembly. The two types of torque measurement are reaction and in-line, which are important when selecting the type of torque transducer to use in your test. The wrong torque can result in the assembly failing due to several problems, whether that is by torque testing bolts or engine parts. Parts may not be assembled securely enough for the unit to function properly, or threads may be stripped because the torque was too high, causing the unit to fail. Torque is a force producing rotation about an axis. This type of testing is also extremely popular in automotive to measure a variety of components.
Shear strength is the ability to resist a “sliding past” type of action when parallel, but slightly off-axis, forces, applied in the test. Shear force is directional force that is over the top of a surface or part. Shear is measured by tension or compression using a shear or bending beam load cell.
Hardness testing, which measures the resistance of any material against penetration, is performed by creating an indentation on the surface of a material with a hard ball, a diamond pyramid or cone and then measuring the depth of penetration. Hardness testing is categorized as a non-destructive test since the indentation is small and may not affect the future usefulness of the material. There are a wide variety of hardness testing types as well.
Examples of Testing Types
Interface’s customer wanted to measure the amount of compression force a piece of candy could withstand to ensure its label is marked correctly. The purpose of the test was to correctly calibrate the equipment to provide the same stamping force each time without breaking the candy apart. An Interface Model WMC Mini Load Cell and 9330 Battery Powered High Speed Data Logging Indicator are used to measure the results. Read more about this compression test here.
In this example torque testing accurately measures the forced needed to securely fasten a bolt. This type of test is critical in highly regulated industries like aerospace and automotive to ensure every screw and bolt are not over or under-tightened. Interface’s LWCF Clamping Force Load Cell along with Interface’s INF-USB3 Universal Serial Bus Single Channel PC Interface Module provide a solution that monitors the force being applied during bolt tightening.
This example shows how aerospace manufactures use shear testing to measure the affects of wind as it moves past the wings, hull, and other components of a plane. Interface measured this force using a Model 6A154 6-Axis Load Cell mounted in the floor of the wind tunnel, and connected to the scaled model by a “stalk”. A BX8-AS Interface BlueDAQ Series Data Acquisition System was connected to the sensor to collect data.
As products become more complex and technologically advanced, the test and measurement industry must provide solutions to monitor a wide variety of factors. This is no different in force measurement.
Interface has been involved in every type of force measurement type across a variety of applications both large and small. To learn more about our more than 36,000 product SKUs designed to conduct all these tests, from single load cells and torque transducers to complete testing rigs and systems. We also provide calibration services for all types of force measurement transducers. Contact us if you are unsure which force measurement solution best fits your testing plan.
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