Define Projectile Springs

During the generation of nodes and/or elements, BALANS attempts to estimate the spring locations and spring stiffness values. In most cases, these numbers will need to be modified based on test data or an external analysis.

For this analysis, the spring at the obturator (Spring 1 at node 7) is a linear spring with a displacement of 1 mm and a force of 875634 Newtons; this corresponds to a spring stiffness of 875634.0 N/mm or 5000000.0 lb/in. The spring at the obturator is generally stiffer than the forward spring.

The forward spring (Spring 2 at node 11) is a non-linear spring; non-linear springs always have more than one segment. The non-linear spring in this model requires two segments to represent the initial radial gap between the bore and the bore riding surface. The first segment has a displacement of 0.0051 mm and a force of zero; this represents an initial radial gap of 0.0051 mm between the bore riding surface and the bore. The second segment has a displacement of 25.40511 mm and a force of 8655810 Newtons; this corresponds to a spring stiffness of 340711 N/mm or 1945514 lb/in.

The edited spring data is shown below. The spring data is at the bottom of the Nodes/Springs tab.