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Ford Motor Company

Including Bolt Pre-Tension Effects in Durability Analyses

About this user story

Durability is one of the trickiest analyses to perform in CAE. In the automotive industry, several parts are made of stamped steel and then assembled together using welded joints or threaded joints. For simplicity, over the years, threaded joints have been modeled as rigid attachments between components, not taking into account the effects of torque tightening of bolts. The sheet metal around the head of the bolt and nut have an initial deformation and stress because of local compression that directly affects the durability results.

In this study, Abaqus is used to generate an FE model for sheet metal parts attached by bar elements that represent the bolts. These are pre-tensioned to apply an initial condition of local stress. Then, the durability analysis takes into account the deformed structure for modal analysis and the calculation of modal participation factors, as well as an initial stress that can directly shift the local mean stress. Modal participation factors are calculated for the model and then converted in nCode software into time series, that can be applied to recreate a dynamic analysis for durability using standard EN glyphs.

Presenter: Daniel Ramos, Ford Motor Company (Mexico)

Originally presented on May 14, 2014 at the 2014 HBM-nCode Products User Group Meeting in Livonia, Michigan (USA).

Piecewise Trend Removal Using nCode GlyphWorks

About this user story

Learn how the Customer Correlation department at Ford Motor Company develops fatigue profiles for target customers using nCode GlyphWorks to automate trend removal from signals.

When undesired trends are present in signals that do not typically oscillate about a mean value, nonlinear trend removal becomes difficult and tedious. This presentation will demonstrate one method for removing nonlinear trends in this type of signal. The general approach is to use information in external signals to identify reference points throughout the sample period. These reference points are used to construct a complex line representing the unwanted trend component of the signal so that it may be removed. Glyphs used in this process include:  time series calculator, looping super glyph, curve fitting, multicolumn manipulation, and conversion from multicolumn to time series.    

Ryan T. Butts, Ford Motor Company

Originally presented on May 15, 2014 at the 2014 HBM-nCode Products User Group Meeting in Livonia, Michigan (USA).

The Customer

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