NISA II STATIC/DYNAMIC/COMPOSITE

NISA II is used for the prediction of stress, strain and deflection under the influence of various kinds of loading using linear/nonlinear analysis techniques, including efficient direct (frontal and sparse) and iterative solvers. NISA has capabilities in modal analysis, test/analysis correlation and model updating, vehicle system analysis, power train mechanical/thermal analysis, muffler and duct analysis.

NISA is recognised as a leading program for the accurate and efficient analysis of composite structures using state-of-the-art solution methods, convergence techniques and time integration schemes. Element types include:

• 3D Layered Composite Shell
• 3D Layered Sandwich Shell
• 3D Solid
• Axisymmetric Layered Composite Solid

NISA Ship Analysis in DISPLAY IV

NISA has extensive capabilities in the analysis of strength and failure behavior of composite materials under a variety of loads and environmental conditions. Loading conditions include biaxial loads, multiaxial loads and blast loads along with heat transfer scenarios. Many composite aircraft wings and fuselages and automotive dashboards and shells have been analysed with NISA, with the following features

• No restriction on the lamination
• Variable thickness and rotation angles
• Edge effects and delamination can be predicted
• Nodal temperatures and temperature gradients may be specified
• Temperature dependent material properties
• Interlaminar stresses satisfying 3D equilibrium equations

Failure Theories include:

• Maximum stress
• Modified Hill-Mises
• Tsai-Wu
• Delamination

The composites module is directly integrated with DISPLAY III/IV for results postprocessing

NISA is used extensively to measure forces induced in structures by earthquake, study the effects on the supporting soil, and look at soil-structure and structure-soil-structure interactions. NISA is used for the estimation of natural frequencies for simple to complex systems and valuation of dynamic response under the influence of various loads such as time varying, harmonic, shock and probabilistic. Seismic analysis is one of the most popular applications of NISA.

• Graphical representation of lamina thickness and angles across the laminate
• Draping of fabric over surfaces of general curvature
• Plots of original and/or deformed geometry
• Contour plots in any layer of displacement, stress components, and stress resultants
• Filtered stress output
  • The ratio of actual to allowable stress is computed. The output is suppressed if this ratio is below the user specified filtering stress ratio
• Stress survey plots
  • This special survey plot searches for the most critical stress ratio in all layers of each element. prints an integer number, representing the most critical percentage of allowable stress on each element
• Largest magnitudes of the displacement vector
• Highest stress resultants in descending order of magnitude