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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 Test

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 Test

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 Test

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 Test

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 Test

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

Compression Test Example

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.

Torque Measurement Example

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.

Shear Test Example

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.

Additional Resources

Tensile Testing for 3D Materials

Material Tensile Testing

Interface Solutions for Material Testing Engineers

Bike Handlebar Fatigue Testing

Interface Specializes in Fatigue-Rated Load Cells

Specifying Accuracy Requirements When Selecting Load Cells

Spring Compression Testing App Note

Insights in Torque Testing Featured in Quality Magazine

Interface Solutions for Material Testing Engineers

Force measurement inherently is part of all types of engineering throughout the entire development process of products, structures, consumer goods, and the materials used to construct them.

In the beginning of the design and development processes, material testing engineers utilize sensor technologies and instrumentation to measure the durability, fatigue, safety, and quality of the materials used for their projects.

The role of a materials engineer is to develop, process, combine, and test materials to be used in production. Based on data gathered, combined with their expertise, the materials engineer will identify and recommend the appropriate materials for specific applications. Ultimately, they are the foundation of product development because it is their responsibility to select materials based on the use of the product, its ability to perform its task and function, and durability of materials to hold up over time. They also test for environmental impact and exposure considerations.

Five Categories of Material Testing

  • Mechanical testing
  • Testing for thermal properties
  • Testing for electrical properties
  • Testing for resistance to corrosion, radiation, and biological deterioration
  • Nondestructive testing (NDT)

Force measurement is most often used is in the material testing category of mechanical testing. This applies to testing materials used in all types of industries, including infrastructure, aerospace, automotive, industrial automation, manufacturing of consumer goods and in the machines used to assemble products. In mechanical testing, Interface sensors are commonly used to conduct:

  • Hardness Testing
  • Tensile Testing
  • Impact Testing
  • Fracture Toughness Testing
  • Creep Testing
  • Fatigue Testing
  • Nondestructive Testing

Interface Material Test Engineer Solutions

Material testing has been around since the first invention, to determine quality, durability and resilience of products and parts. What has changed over the centuries and decades is the sophistication of force testing and measurement. Interface’s robust line of load cells, torque transducers, multi-axis sensors, and instrumentation are used in about every industry for material testing. If it must be measured, Interface has a solution.

Interface’s force measurement products are being used to gather data from testing materials in applications used for industrial automation, structures, medical devices, vehicles on the ground and in the air, packaging, sports equipment and more. Material testing engineers ensure reliability and safety of the chosen materials. Here are examples of how material testing engineers use our products.

Tensile Testing of 3D Printing Materials

Interface was contacted by a test engineering team in search of a solution for conducting a tensile force test on different 3D printing materials until failure. They wanted to test several types of material types. The 3D printing materials to be tested to see how it performed included PLA, PETG and ASA.  The test of the materials was to assess strength, quality, ductility, and stiffness. Interface supplied our most popular load cell, the 1200 Standard Precision LowProfile™ Load Cell, to install into the engineer’s test frame. The tensile test gathered the force results from the load cell that was synced through Interface’s instrumentation solution, the INF-USB3 Universal Serial Bus Single Channel PC Interface Module. The results were displayed on their computer with supplied software from Interface. Read more about this material testing application solution here.

Bike Frame Fatigue Testing

Fatigue testing is a critical material test used to ensure the materials used in a product hold up over time. A bike manufacturing company wanted to perform a fatigue test on their bike frames to analyze the strength of their frames, ensure durability and high-quality standards. Interface suggests installing Model 1000 Fatigue-Rated LowProfile™ Load Cell to the customer’s bike frame fatigue tester. This load cell will provide the customer highly accurate results through the fatigue cycling. Results are collected using the INF-USB3 Universal Serial Bus Single Channel PC Interface Module and displayed on the customer’s computer with Interface’s provided software. The bike manufacturing company successfully had their bikes undergo fatigue frame testing, receiving highly accurate results with Interface’s load cell and instrumentation. Watch the fatigue testing of the bike frame in this animated app note.

Spring Compression Testing

A customer wanted to evaluate the performance of their springs, but also the functionality of their spring test stand with a wireless solution. Interface suggested using one of their WTS-5200XYZ 3-Axis Force Moment Load Cell which has three integral WTSAM-1E Wireless Transmitters and installing it into the customer’s spring compression frame. The WTS-5200XYZ 3-Axis Force Moment Load Cell measured the force compression of the spring. The integral WTS-AM-1E Wireless Strain Bridge Transmitter Modules transmitted and displayed the information wirelessly to the LCCAXXX Wireless Instrument Enclosure. Using Interface’s solution, the customer was able to wirelessly get compression results on the spring being tested. They were also able to verify their spring compression test stand was working effectively.

Selecting the right material is critical to product develop and material testing engineers rely on Interface due to the accuracy and reliability of our solutions. If you have questions on what products are best suited for your material testing applications, please contact us.

ADDITIONAL RESOURCES

Tensile Testing for 3D Materials

Furniture Fatigue Cycle Testing

Bike Handlebar Fatigue Testing App Note

Aircraft Wing Fatigue App Note

Material Tensile Testing

Why Civil Engineers Prefer Interface Products

Beam Stress Test

Taking Flight with Interface Solutions for Aircraft Testing

As a top supplier of premium force measurement solutions for the aerospace industry, one of our critical areas requiring precision accuracy and high-quality products is for testing airplanes. Interface load cells, torque transducers, and instrumentation are used regularly in testing of all types of aerospace apparatus, components, and machines, along with embedding our force sensors in aircraft for ongoing simulation tests and inflight data acquisition.

Aircraft, spacecraft, military, and defense companies such as Boeing, Airbus, Lockheed, Northrop Grumman, Bombardier, Embraer, Gulfstream, NASA, and Cessna and many others in the supply and production lines utilize Interface load cells for thrust, wing, static, and fatigue testing. While structural test applications use many types of LowProfile™ load cells, Interface also offers a wide variety of load washers, load buttons and miniature tension and compression load cells for test, production, and control monitoring applications for aircraft.

Why do aircraft testing professionals prefer Interface solutions?  One reason is our moment and temperature compensated load cells use proprietary alloy strain gages for extreme accuracy and reliability that is unmatched by other brands. Using eight proprietary strain gages per sensor, our 4mV/V output well exceeds the performance requirements for testing these specialized aerospace vehicles.

In addition, before the airplanes are even assembled, every manufactured part and components must go through rigorous testing. There are hundreds of machines that are used on the production line for the hundreds of thousands of components needed to complete these specialized craft. Interface load cells and torque transducers are found on many of these production and test machines. Our products are used to provide a wealth of insight to guide manufacturers through research, development and final build. Because testing is so inherent for any of these parts, Interface products provide reliability and accuracy when there are no exceptions.

We recently developed several new application notes on ways our products are used to test airplanes. Included below is a preview of a few of the latest additions to our application notes catalog.

Jet Engine Thrust Test

A customer wanted to conduct a static jet engine thrust test that can accurately determine the engine’s thrust, burn time, chamber pressure, and other parameters, providing invaluable data to propellant chemists and engineers. They needed a high accuracy load cell with excellent repeatability to withstand thrust forces in very harsh environments. Interface offered a 1000 High Capacity Fatigue-Rated LowProfile™ Load Cell, which is ideally suited based on their performance for this application. The load cell reacts to the thrust forces produced by the jet engine and the signals are collected and recorded to create a “thrust curve” of the engine. The performance of an Interface LowProfile™ Load Cell allowed the engineers to be confident in the data acquired from the static testing. Additionally, the repeatability of the load cell results in reduced time between tests, making static jet engine thrust testing more efficient. Read the new Jet Engine Thrust Test application note here.

Aircraft Yoke Torque Measurement

An aircraft manufacturer wanted to measure the torque of their aircrafts yoke or control wheel. They also wanted to monitor the torque and forces applied to ensure that the aircrafts controls are operating properly. Interface suggested using the AT103 2-Axis Axial Torsion Load Cell to measure both torque and force within this single sensor. It can be installed inside of the yoke, and can measure the rotation of the yoke, and the forward and backwards movements. Data can be measured and paired with the SI-USB4 4-Channel USB Interface Module and displayed with the customer’s laptop. Using this solution, the customer was able to measure and monitor the torque and force of the yoke control. Read the Aircraft Yoke Torque Measurement application note.

Aircraft Engine Hoist

An aerospace company wanted to test their aircraft engine hoist in order to safely lift, remove, or install engines efficiently and safety. Interface’s solution was to install WTSSHKB-HL Wireless Bow Shackles to the aircraft engine hoist. A heavy load was added to the hooks where the aircraft engine would be. Results from the heavy load are then sent wirelessly to both the WTS-BS-4 USB Industrial Base Station attached to the customers computer or laptop, and the WTS-1-HS Handheld display for single transmitters. With these products, the customer was assured that the aircraft engine hoist was strong and secure enough to lift a heavy engine when installing or removing an engine inside of an aircraft. Learn more about the Aircraft Engine Hoist application here.

Our expert application engineers help our customers by providing technologies that provide exceedingly accurate measurement used in all types of testing, including structural, static and fatigue. For more information on Interface and its solutions designed for airplanes and other aerospace applications, please visit https://www.interfaceforce.com/solutions/aerospace.

Additional Aircraft Testing Resources

Aircraft Wing Fatigue App Note

Aircraft Screwdriver Fastening Control App Note

Aircraft Lifting Equipment App Note

Examining Interface Aerospace Industry Solutions

 

 S-Type Load Cells 101

There are many different types of devices used in test and measurement from load cells to torque transducers and tension links to multi-axis sensors. In addition, there are sub-categories in each of these product types that are based on various specifications, capabilities, capacities, and application requirements.

Discussing load cells specifically, there are different models and configurations depending on the use case, the amount of force measurement or weighing requirements for a particular load, dimensions, and even test environment considerations. No matter what our customers need, we have standard and custom load cells up to the task. In our 101 series, we are highlighting the innovative miniature load cell sub-category of Interface S-Type Load Cells.

What Is an S-Type Load Cell and What Is It Used For?

S-type load cells, sometimes called s-beam, gets its nomenclature from the “S” looking model of the load cell. It is shaped this way because it is designed to measure well-controlled tension and compression forces. There are preferred by engineers and testing labs for the precision, size, material, and ability to fit in limited spaces. They are often used for weighing, in test machines as well as product designs for ongoing performance measurement by OEMs.

An s-type load cell will often be used within a system designed to stress test products in a controlled environment for fatigue and product testing to measure the way the product stands up to force over long periods of time. The benefit of Interface S-Type Load Cells is that they are very cost-effective, highly accurate, easy to mount, and offer flexibility because it can be used universally for tension and compression testing. They are also smaller than typical load cells, providing major benefits when there are limitations in space or for smaller test product dimensions.

Interface has a wide range of specialized miniature s-type load cells including sealed, micro-size, fatigue-rated, high-temperature ratings, low height, overload protected and intrinsically safe to meet all types of testing protocols and plans. You can see all the s-type models here.

An s-type load cell is generally used with eyebolts or rod-ends when used in tension and this can cause binding or the associated hardware to unthread. These uniquely designed load cells should not be used when weighing an object that can sway or rotate. Additionally, an s-type load cell is not recommended when the load cell will be used for both tension and compression, where accuracy in compression is critical. In this case we’d recommend a shear type of load cell.

S-Type Load Cell Applications

Prosthetic Load and Fatigue Testing

Prosthetic limbs must be tested for extreme loading that can occur during falls, accidents, and sports movements. Fatigue testing of prosthetic components determines the expected lifespan of the components under normal usage. Interface suggested a static load test apparatus using SSMF Fatigue Rated S-Type Load Cell attached to hydraulic actuators to apply and measure loads. The fatigue testing machine uses SSMF Fatigue Rated S-type Load Cell to apply and measure cyclic loads. During the fatigue test, the actuator repeatedly applies and removes the force to simulate activity such as walking. Tilt tables may also be used to apply forces at various angles to simulate the heel-to-toe movement of walking or running. Using this solution, engineers can determine whether prosthetic materials and designs will withstand the rigors of daily use and occasional high load situations. Read more here.

Furniture Fatigue Cycle Testing

To meet safety protocols in relation to the manufacturing of various furniture products, fatigue testing, shock testing, and proof testing must be rigorously performed before diffusion into the marketplace. Force testing simulations on furniture products are critical in determining the posted max loads to protect manufacturers from liability due to damages that might result from the misuse of those products and overloading. Using an Interface Model SSMF Fatigue Rated S-Type Load Cell along with Interface Model 9890 Strain Gage, Load Cell, & mV/V Indicator provides a solution that measures the force being applied in fatigue cycle testing of a furniture product, in this case testing the rocking mechanism in an office chair. Unlike other similar load cells, the Model SSMF is fatigue rated making it highly suitable for fatigue testing. No fatigue failure of any fatigue-rated Interface load cell, used within its ratings, has ever been reported. The furniture manufacturer was able to obtain accurate data about the rocking mechanism the office chair as it was fatigue cycled into failure. Adjustments were made to the design to improve the safety and life of the furniture, ensuring product quality and protecting the manufacturer from future liability. Read more here.

Interface S-Type Load Cells are highly effective, accurate and flexible products used for a wide variety of applications needing compression and tension force testing. To learn more about Interface’s S-Type Load Cells, you can also visit here or call us today to speak to an application engineer who can help you select the right product for your next project at 480-948-5555.

Interface Specializes in Fatigue-Rated Load Cells

Often test protocols require a fixed load plus a dynamic load to be applied to a test sample simultaneously. Interface Fatigue-Rated Load Cells are well suited for this requirement. Fatigue-rated is a specification that defines a special class of load cell design and construction used for repetitive cycle and fatigue testing.

Interface has specialized in fatigue-rated load cells and their applications since our founding in 1968.  The stringent discipline that is necessary to produce true fatigue-rated load cells, with consistency, is why Interface is known for this specialized load cell design and construction.

Manufacturing these special types of load cells, we can proudly state there is no record of reported fatigue failure for Interface Fatigue-Rated Load Cells used within their specified ratings. Interface fatigue-rated load cells have a given service life of 100 million fully reversed, full capacity loading cycles. It’s why reliability, durability, and quality rank these types of load cells as best-in-class for fatigue and cycle testing.

The use of fatigue-rated load cells and data logging instrumentation are used for testing materials, parts, or assemblies for weakness, and often ultimately to destruction. These types of fatigue tests are valuable to have an accurate record of the forces applied at every moment of a test to analyze stresses, identify fatigue and potential failure risks.

INTERFACE FATIGUE-RATED LOAD CELLS:

  • 1000 Fatigue-Rated LowProfile® Load Cell Model 1000 series is a fatigue-rated low profile load cell with 300% safe overload, extremely low moment sensitivity of 0.1%/in and a higher fatigue life. Capacities give you options to measure 1 pound (4.45N) and up to 1 million pounds (4500kN) of force.
  • 1000 High Capacity Fatigue-Rated LowProfile® Load Cell With many variants and configurations our fatigue-rated load cells provide up to 100 million fully rendered cycles. The gaged sensors in every load cell are individually inspected, tested, and certified to meet our rigid standards.
  • 1500 Low Capacity LowProfile® Load Cell – The Interface Model 1500 is a fatigue-rated unique LowProfile Load Cell designed for low capacity applications where low sensitivity to eccentric load is important.

Each fatigue-rated load cell model grouping also has numerous capacities and variations, including additional bridge options. All product variations, capacities, customization options and availability are online. There are possibilities to have engineered-to-order made products and customized solutions, as with all Interface manufactured load cells.

When passing fatigue testing is critical to the success of an assembly, piece of equipment or product, engineers and manufacturers rely on Interface Fatigue-Rated Load Cells. Our fatigue-rated load cells are used by most manufacturers of test machines, aircraft, spacecraft, auto and transportation vehicles, and various devices and industrial systems.

Here are a few fatigue-rated applications that demonstrate different use cases:

Furniture Fatigue Cycle Testing App Note

Bike Frame Fatigue Testing App Note

Aircraft Wing Fatigue App Note

Prosthetics Load and Fatigue Testing App Note

Additional reading on this subject can be found here in the post, Considerations for Fatigue-Rated Load Cells. If you are exploring fatigue-rated load cells or products for cycle testing, contact our application engineers to answer questions and ensure you get the right product for your testing needs.

The Role of Actuators in Force Measurement

One of the most common force measurement tests in the engineering and manufacturing world is called cycle testing. Cycle testing involves constant force being applied to a component or product over hours, days and even months. The goal is to test a product to find out how long it will last under the amount of force it will see in use in the real world.

Cycle testing is used throughout different industries. One of the most common applications of a cycle test is on something like airplane wings. The wings of an airplane are exposed to constant push and pull force to guarantee that they will hold up over many flights. Check out the wing fatigue testing application note here.

Another example is simple furniture tests, like a chair, to ensure it can withstand the weight of people of all sizes after years and years of use. These tests are designed to really push the limits on the product so engineers and manufacturers can confirm their designs and ensure safety and durability.

To carry out these tests, actuators are used to generate the force in cycle testing. An actuator is a component responsible for moving and controlling a mechanism or system. Actuators are small components that convert energy in a linear moment. There are a variety of different types of actuators including linear, rotary, hydraulic, pneumatic, and more. Each is designed to create force in different directions and on different axes.

Actuators are very important because force measurement is fed back into a control loop and the actuator allows you to accurately control how much force you’re putting on a test article. As a basic example, if you wanted to measure how much force it takes to close a door, you would use an actuator to provide the door closing force while the load cell measures the amount of force given off by the actuator.

Interface often integrates actuators into load cells for custom solutions to use in rigorous use and cycle testing. These types of custom solutions are used by equipment and product manufacturers, OEMs, as well as product design and testing labs. There is increasing frequency for OEMs to integrate actuators into load cells for testing their automated testing lines or products in use for continuous feedback.

For example, mobile device manufacturers use a miniature–sized load button load cell like the ConvexBT to test the pressure sensitivity of the touch screen. By using an actuator, phone manufacturers can set up an automated test lines with an actuator integrated in the load button load cell to test each screen as they go across a test line. You can read more about ConvexBT in this new white paper.

Another major application for actuators is in calibration machines. To test if a load cell is calibrated correctly, an actuator applies force to the load cell being tested and a calibration grade Gold Standard Load Cell simultaneously. These measurements can tell the user if the load cell needs to be recalibrated or not because the actuator allows the user to create a very precise force measurement. If measurements on the test load cell are not the same as the control load cell, the user knows it is off calibration and it’s time to schedule a calibration service.

From custom solutions to calibration, if actuators are necessary for your next project learn how Interface can work with you to find a solution that meets your precise needs.

Read more about Gold Standard Calibration Systems here.

Learn about how Interface is a preferred provider of OEM solutions here.

Considerations for Fatigue-Rated Load Cells

There are many products that are made to serve a single or limited use. Needs for these types of products, often consumable, are immediate and buying decisions usually require limited research or comparisons. On the other end of the spectrum, there are products that need to be extremely reliable, durable, and built to last a long time. The buying decisions for these types of products often require more research to make certain they are highly rated, safe, and made from sturdy and reliable materials.

How do original equipment manufacturers (OEMs) determine how long a product should last with consistent use? What design decisions need to be made to improve product reliability? The answer is often found in the defined fatigue requirements of a product. In the test and measurement and design phase of a product, answers to these questions frequently require product and component testing with fatigue-rated load cells.

Fatigue is the weakening of a material caused by repeatedly applied loads. Similar to if you repeatedly bend a paper clip, it will eventually weaken and then break. The only way to test fatigue is to put prototypes of the product through stress tests for long periods of time or use an apparatus that tests the lifetime “wear and tear” in a few hours. The tool that reports the data gathered from stress tests is the load cell.

With Interface fatigue-rated load cells, designers and engineers can predict the time and force it will take for wear and tear to take its toll on their products. They can then create safety instructions for customers or redesign the product for better results.

Interface Model 1000 series is a portfolio of fatigue-rated low profile load cells with 300% safe overload, extremely low moment sensitivity of 0.1%/in and higher fatigue life. If you need to measure 1 pound (4.45N) or 1 million pounds (4500kN) of force, Interface fatigue-rated load cells are built for this type of testing.

Interface fatigue-rated load cells are designed for an operational life of in excess of 100 million fully reversed cycles.

It’s also important to note that Interface fatigue-rated load cells are based on fully reversed load cycles, which means they are rated for two directions. This type of loading cycle is considerably more stringent than unidirectional loading. It is the more common application of load cells. If a fatigue load cell is repeatedly loaded in only one direction, it can be loaded to about 133% of the bidirectional fatigue-rated capacity with no degradation of its fatigue rating.

Interface works with customers to provide our fatigue-rated load cells for products that can’t fail. It is our mission to ensure precision products are safe, reliable and durable. If they do fail, it could result in significant harm.

Two examples of products dependent on fatigue-rated load cells for testing are aircraft wings and furniture stability. In aircraft wing testing, load cells test the materials used to build the wings to ensure they are strong and lightweight. The load cells are also used in wind tunnels to test the stress of high winds on the wings over time. Safety protocols manufacturing for furniture products require fatigue testing, seat testing, shock testing, and proof testing. These tests must be rigorously performed before entering the marketplace.

Force testing simulations using fatigue-rated load cells help the manufacturer define max loads in order to protect manufacturers from liability due to damages resulting in the misuse or overloading of their products. These types of applications require the most accurate data available provided by our load cells to ensure that testing results produce a quality product that lasts.

Fatigue-rated load cells are one of the many Interface force measurement tools available to help customers develop quality products. For information on all of the load cells we provide, please visit www.interfaceforce.com/product-category/load-cells/.

Contributor:  Jay Bradley, Sr. Electrical Engineer, Interface

Interface Accelerates Accuracy in Test and Measurement

Since Interface was founded in 1968, we have developed millions of load cells and torque transducers for engineers and designers that require the highest precision force sensors for accurate and reliable data collection in test and measurement (T&M). Our customers represent a wide swath of industries, products, equipment types, tools, and electronics that depend on us for proving accuracy, consistency, and reliability in performance.

The complexity of user applications and testing environments is rapidly expanding as a result of shorter product lifecycles and demands for smaller, lighter, faster-performing innovations. This has created a proliferation of new test and measurement use cases for sensors in almost every sector including technology, energy, and biomedical, as well as industrial, additive manufacturing and automotive verticals.  We are seeing more and more sensor products utilize Bluetooth technology, digital outputs, and direct OEM installations into the product without connectors.

Our products serve a wide variety of these types of test and measurement requirements used for structural and material testing, static and fatigue testing, torsion effects, tension tests and mass and kinetic energy. When experienced users see the Interface brand, they know they can expect the highest-quality results possible from the force measurement industry leaders.

The load cell products we provide T&M customers range from our  Ultra Low Capacity Series, which measures forces in mere grams, to our industry-leading LowProfile™ Load Cells with capacities up to 2 million lbf. For torque testing, Interface supplies a wide variety of torque transducers with ranges as low as 0.005 Nm and as high as 340K Nm. We customers depend on us for various multi-axis sensors, instrumentation products, accessories, tension links, load pins, and shackles. For complex challenges and unique applications, our customers work with our application engineers to create modified and customized solutions.

Test and Measurement Applications

To give you a sense as to the range of test and measurement use cases, here is a small sample of applications that utilize our standard and custom force measurement solutions:

  • Fatigue testing
  • Material testing
  • Suspension testing
  • Shear testing
  • Force testing
  • Tensile testing
  • Pressure testing
  • Friction testing
  • Durability testing
  • Tension testing
  • Device testing
  • Hardware load and fatigue testing
  • Force verification
  • Calibration

Included below are two examples of how our products were used to help our customer’s test and measure “real life” applications.

Harness Durability Testing

A customer came to us needing to test the load and durability factors of harnesses used by workers to carry heavy loads or those used in sports equipment. We developed a drop test apparatus using an Interface Model 1200 Load Cell. The apparatus dropped a humanoid dummy outfitted with the harness from various heights to measure the force generated during sudden stops at maximum cable extension. These tests helped our customer develop harness limits which inform users on unsafe loads.

Figure one: Interface drop test apparatus using the Model 1200 load cell

Prosthetic Load and Fatigue Testing

Medical hardware engineers are among the largest users of T&M equipment because of the stringent regulations in the industry. Interface developed a new solution to test heavy loads on prosthetic limbs to certify them for falls, accidents and athletic movement. These stress tests determine the expected lifespan of prosthetic components under normal usage.  Our solution involves a static load test apparatus with an S-type load cell attached to a hydraulic actuator which applies and measures cyclic loads. These tests help our customers determine whether prosthetic materials and designs will withstand the rigors of daily use and occasional high-load situations.

Figure two: Load test apparatus with an S-type load cell attached to a hydraulic actuator  

What we find most exciting about the T&M industry is continuous innovation, perhaps it is the “engineer” in us.  We like to solve, create, build, imagine and challenge ourselves. There are a wide variety of new applications we see every year, and yet many applications are unique.

Those that are in the test and measurement field help to guarantee product safety, reliability and longevity. Therefore, the tools they use are critical to the confirmation of their work. That’s why Interface builds products that reliably and consistently gather high-quality, accurate data for any application. For more information on our T&M offerings, or to discover more T&M product applications, please visit www.interfaceforce.com/solutions/test-measurement/.