UNCORKED: THE FORCES FOR PULLING A CORK – LOAD RECONSTRUCTION
Tim Hunter, Ph.D., P.E.
President, Wolf Star Technologies, LLC
When modeling even the simplest of mechanisms, the need to understand real world loading is imperative for proper simulations. Traditional approaches may use company standards or even MBD simulations. However, these approaches are at best approximations of the actual load conditions. If using an approximation of loading in a simulation, the results are only as accurate as the approximation. Companies often use experimental load transducers to measure real world loading. There are two major disadvantages with this approach. The first is that the load transducers often cannot measure all the desired load inputs for a simulation. The second disadvantage is that the application of the load transducer forces physical modifications of the subject components. The measured loads may not be the actual loads because of the mass and stiffness changes to the subject components. Experimental Load Reconstruction is a non-invasive solution to this problem. The commercial True-Load® Load Reconstruction software will be demonstrated in this application. An unmodified corkscrew is used in this application with only uniaxial strain gauges applied to the corkscrew.
Presented will be an example of using True-Load Load Reconstruction technology to understand complex loading on an off-the-shelf corkscrew. This approach will involve the creation of an FEA model of the corkscrew. The corkscrew will have unit loads applied to the corkscrew. These unit loads will be used to construct a correlation matrix relating strain response to applied loading. The operation of the corkscrew will be used for pulling wine bottle corks. As will be seen, the loads will vary greatly from bottle to bottle.
The advantage in this approach is to get real world structural loads which can be used to drive accurate FEA simulations. Every test event is different; thus, the loading profiles are different. Traditional analytical techniques idealize the conditions and loading environment. The real world is complex, and every event is unique. True-Load loads provide real world loads for real world simulation.
DOWNLOAD WOLF STAR TECHNOLOGIES CORKSCREW LOAD RECONSTRUCTION PAPER
(PDF - 2.08 MB)
Typical Reconstructed Operating Deflection Shape
Load Reconstruction Process Schematic