Pagnotta Engineering, Inc.

NON-LINEAR ANALYSIS

When ductile metals are loaded past their elastic limit, the instantaneous modulus decreases resulting in larger deflections,
or strains, than linear analysis would predict. Often, non-linear analysis can result in less conservative and more realistic
stress results since loads can redistribute through redundant load paths.

Non-linear Material | Large Deformation

EXAMPLE PROJECT:
Battery Cell Pressure Vessel
(used as spacecraft power source)

CUSTOMER:
Eagle-Picher Technologies, LLC

ANALYSIS SERVICES PERFORMED:
• Finite Element Model of pressure vessel created taking advantage of axisymmetric properties
• Stress-strain curve for vessel material defined
• Non-Linear Stress Analysis of Pressure Vessel performed to determine strains and extent of
plastic region
• Stress results used to evaluate fatigue-life of electron beam and laser welded joints in vessel



FEM mesh of wedge of cell assembly using symmetry	Von Mises stress contour of proof loading to 1582 PSI