Publications

Proposed for publication in Wind Energy.

Veers, Paul S.; Lobitz, Donald W.

Abstract not provided.

Lobitz, Donald W.; Veers, Paul S.; Eisler, G.R.

Abstract not provided.

Lobitz, Donald W.; Gregory, Danny L.; Smallwood, David O.

When embarking on an experimental program for purposes of discovery and understanding, it is only prudent to use appropriate analysis tools to aid in the discovery process. Due to the limited scope of experimental measurement analytical results can significantly complement the data after a reasonable validation process has occurred. In this manner the analytical results can help to explain certain measurements, suggest other measurements to take and point to possible modifications to the experimental apparatus. For these reasons it was decided to create a detailed nonlinear finite element model of the Sandia Microslip Experiment. This experiment was designed to investigate energy dissipation due to microslip in bolted joints and to identify the critical parameters involved. In an attempt to limit the microslip to a single interface a complicated system of rollers and cables was devised to clamp the two slipping members together with a prescribed normal load without using a bolt. An oscillatory tangential load is supplied via a shaker. The finite element model includes the clamping device in addition to the sequence of steps taken in setting up the experiment. The interface is modeled using Coulomb friction requiring a modest validation procedure for estimating the coefficient of friction. Analysis results have indicated misalignment problems in the experimental procedure, identified transducer locations for more accurate measurements, predicted complex interface motions including the potential for galling, identified regions where microslip occurs and during which parts of the loading cycle it occurs, all this in addition to the energy dissipated per cycle. A number of these predictions have been experimentally corroborated in varying degrees and are presented in the paper along with the details of the finite element model.