AN EFFICIENT CRANKSHAFT DYNAMIC ANALYSIS USING SUBSTRUCTURING WITH RITZ VECTORS

✍ Scribed by Z.P. MOURELATOS

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 420 KB
• Volume: 238
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.2000.3208

✦ Synopsis

A structural analysis using dynamic substructuring with Ritz vectors is presented for predicting the dynamic response of an engine crankshaft, based on the "nite-element method. A two-level dynamic substructuring is performed using a set of load-dependent Ritz vectors. The rotating crankshaft is properly coupled with the non-rotating, compliant engine block. The block compliance is represented by a distributed linear elastic foundation at each main bearing location. The sti!ness of the elastic foundation can be di!erent in the vertical and horizontal planes, thereby considering the anisotropy of the engine block compliance with respect to the crankshaft rotation. The analysis accounts for the kinematic non-linearity resulting from the crankangle-dependent circumferential contact location between each journal and the corresponding bore of the engine block. Crankshaft &&bent'' and block &&misboring'' e!ects due to manufacturing imperfections are considered in the analysis. The superior accuracy and reduced computational e!ort of the present method as compared with the equivalent superelement analysis in MSC/NASTRAN, are demonstrated using the free and forced vibrations of a slender cylindrical beam and free vibrations of a four-cylinder engine crankshaft. Subsequently, the accuracy of the present method in calculating the dynamic response of engine crankshafts is shown through comparisons between the analytical predictions and experimental results for the torsional vibrations of an in-line "ve cylinder engine and the bending vibrations of the crankshaft-#ywheel assembly of a V6 engine.

2000 Academic Press