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