Abstract:

In view of the poor calculation accuracy and low efficiency of the initial algorithm of one-step rollover collision due to the tremendous computing efforts in in-plane four-point integration of Mindlin shell element， the irrational iteration mode of generalized unbalanced force and being prone to shear lock， the initial algorithm is optimized from two aspects in this paper. For the optimization of element integration point mode， both in-plane reduced integration and partial reduced integration are introduced， and three integration schemes， i.e. five point-， seven point- and nine point integrations are adopted along the direction of element thickness， which is then matched with in-plane integration. For the iteration mode optimization of generalized unbalanced forces， the separate weighting factor is defined for force and moment， respectively， to calculate the “2” norm of unbalanced force， and by means of calculation time-weighting factor ratio curve， the reasonable weighting factors for both force and moment are determined. Finally， the typical segment of a coach body is chosen as real calculation example， the results of improved algorithm， initial algorithm， LS-DYNA analysis and rollover test are compared， verifying the effectiveness of the improved scheme proposed.

Key words: one?step rollover collision algorithm, integration point mode, reduced integration, gene?ralized unbalanced force, weighting factor