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When a model fails under P-Delta, increase the size and/or quantity of columns and bracing to improve lateral capacity, and thereby avoid buckling. Walls that have been modeled uising using membrane type area element (never recommended) or shells with unrealistic thickness and or low stiffness modifiers can buckle and cause convergence issues. As an alternative, you may also refine the factors and/or loads applied during analysis.
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- Remove auto line constraints. Select all deck/shell objects in the model, then select Assign > Shell Elements > Auto Line Edge Constraint and uncheck the Apply to Full Structure (not just Selection) option. This will remove auto line constraints and possibly resolve instabilities.
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