Bespoke sensors - Replicating Aircraft Components

The testing of aircraft assemblies invariably requires complex test structures to correctly apply representative inflight loads to the specimen. The scale of the test rig depends on the size of the specimen, with whole aircraft tests requiring hanger sized structures to encase the aircraft, but most tests are on smaller sized assemblies or components and even allowing for actuators and linkages are much more manageable. The interface has for many years been the load cell supplier of choice for most aircraft manufacturers for all system, structural and fatigue testing applications. However, reproducing the inflight loads on real specimens sometimes requires measurements to be made within the specimen and the lack of available space can prohibit the use of external force sensors – in this case, an aircraft part may be replicated with a purpose-built sensor. Our approach starts with these questions: What are the dimensions of the existing bolt? What level of loads is to be applied? How much room is there for a cable exit? What is the orientation of the primary load? What are the environmental conditions? What are the life expectancy and the accuracy? Generally, we are working with 3D CAD and once the customer has released the details of the area surrounding the bolt and specified the working conditions we can start the process of designing a bespoke product and negotiating any modifications to the local structure for cable exit, anti-rotation stops or any other required adaption. The solution, for the project that this overview article is based on, required: Replacing the standard hinge bolts in an otherwise standard assembly The decision if a down-hole gauging design is appropriate Special consideration about gauge position due to unsupported region Determine the load path for correct orientation Modification of the structure Introduce a mechanical anti-rotation stop with load orientation Evaluate environment Due to operating temperatures being elevated high-temperature cable was used and the load pin temperature range was characterised to suit Depending on the application this procedure can vary and we have lots of options and experience to help us achieve the most practical solution. Finally, and this can make an enormous difference to the results. As the accuracy of a load, pin can rely heavily on the quality and fit of the calibration loading fittings, we manufacture a unique calibration fixture for every design to accurately apply the loads in the most representative way that best replicates the working conditions. Got a custom project? Then we would like to talk with you.

For more information on Bespoke sensors - Replicating Aircraft Components talk to Interface Force Measurements Ltd