One interesting feature in the ADINA 8.0 version is the bolt option. A pre-stress beam (pipe) element with a given constant force creates a bolt element. Constant pre-stressing is assured by imposing an initial iteration scheme, during which (under no other, external or internal load condition) the pre-stressing force remains unchanged even if the structure deforms. In this analysis, the deformations can be large. The usual time step analysis or other analysis type (frequency, modal superposition, etc.) follows the initial iteration step. An industrial example (about 1 million equations), given to us by John Deere, is depicted above. The bolts are not shown.