Thursday, August 23, 2007

Virtual Crack Closure Technique (VCCT) and Discrete Cohesive Zone Model (DCZM)


Software Suite for Durability, Damage Tolerance, and Life Prediction
Augments FEA Solvers MSC NASTRAN*, ABAQUS, ANSYS & LS-DYNA

* Best Performance and Verified Solutions with MSC NASTRAN



This Week's Feature Highlight: Crack Growth for Metal and Composite

Virtual Crack Closure Technique (VCCT) &
Discrete Cohesive Zone Model (DCZM)

Based on fracture mechanics approach, VCCT (Virtual Crack Closure Technique) and DCZM (Discrete Cohesive Zone Model) can be used to simulate crack growth and are supplementary to the PFA (Progressive Failure Analysis) of GENOA. VCCT is applicable to linear elastic materials. It can also be used as a tool to compute the strain energy release rate and to estimate the fatigue life and residual strength. DCZM has the capability to model the material softening. They are applicable to, but not limited to, delamination of face sheets/cores in sandwich materials, failure analysis of adhesively bonded joints; fast crack propagation and arrest in pipe lines; interface failure analysis in MEMS devices; and crash and crush analysis.

Click here to receive demo and presentation of VCCT & DCZM.

Figure 1 - Boeing 747 Crown Panel Fuselage Section

Figure 2 - NASA Push-off Test with Honeycomb, Adhesive Bond, & Polymer Composite

VCCT and DCZM Features:  
  • Not sensitive to the FEA mesh size.
  • Not require the singular crack element and therefore, they are easy to apply without much extra work in mesh preparation.
  • Calculations are based on the nodal displacements and nodal forces and therefore, they do not increase the problem size and thus are computational efficient.
  • Work with most of commercial FEA software such as MSC.NASTRAN, ABAQUS, ANSYS, LS-DYNA, MSC.MARC and MHOST. 
  • Can be used with material strength theory.
  • Virtually represents damage propagation by element removal, node split, and adaptive meshing techniques. 
  • Supports various loading conditions such as quasi-static, impact, cyclic (low, high and two stage fatigue, random fatigue, PSD fatigue) and creep.
  • Delivers robust computational performance, rapid convergence and efficient CPU time.
  • Captures the load vs. displacement curve after the ultimate load. 
References:
1. De Xie, Zhongyan Qian, Dade Huang, and Frank Abdi, "Crack Growth Strategy in Composites under Static Loading", 47th AIAA-2006-1842, Newport, RI, May 1-5, 2006.  Click here to read the publication document. 

2. Thomas S. Gates, Xiaofeng Su, Frank Abdi, Gregory M. Odegard, and Helen M. Herring, "Facesheet Delamination of Composite Sandwich Materials at Cryogenic Temperatures", Journal of Composite Science and Technology, 2006.
Click here to read the publication document. 

Did You Know?

Trying GENOA on the Web

imageDid you know that you may try out material modeling or 3D analysis through the web without installing GENOA software?  With our Collaborative Virtual Testing software, we allow customers and clients to login to our secure public CVT website and perform analysis on our server. For more information on trying out GENOA through the web, contact our sales at sales@ascgenoa.com.
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Friday, August 10, 2007

Filament Winding (FW) Analysis


Software Suite for Durability, Damage Tolerance, and Life Prediction
Augments Solutions for NASTRAN, LS-DYNA, ABAQUS & ANSYS

This Week's Feature Highlight

Filament Winding (FW) Analysis

As part of the GENOA family, Filament Winding (FW) supports design and analysis of composite over-wrapped pressure vessels (COPVs). FW utilizes advanced composite mechanics and generates information that can be included in the PFA analysis of a COPV design. It can duplicate the manufacturing process by generating the correct tape schedule at each location on the COPV FEM model and calculate the residual stresses caused by the filament winding process.
Filament Winding (FW) Features:  
  • Import finite element models from other software formats.
  • Generate pressure vessels: liner only, composite over-wrap only, or combined liner and composite over-wrap. 
  • Control the bonding between the liner and the composite over-wrap. 
  • Accounts for residual stresses due to the winding procedure and curing during the manufacturing procedure.
  • Outputs the node/element ply schedules (including orientations, materials, and thickness) and internal stress distribution, which depends on the geometry, loads, material properties, environment and filament winding process.
  • Generate finite element model of pressure vessels of several shapes and sizes.
    Supports cylinders with circular, elliptic cross-sections and end caps with elliptic, spherical, geodesic, and toroidal shapes. 
  • Automatically generate filament winding ply schedules upon giving the definition of hoop and helical winding with greater control over the material and fabrication parameters.
  • Allows to simulate complete manufacturing to certification process (static, mechanical and thermal fatigue, and dynamic loading).
  • Design of filament wound pressure vessels for defense, automotive and aerospace applications that account for filament winding processes.
  • Predicts failure location and corresponding load.
  • Create design configurations with increased durability and damage tolerance.

Did You Know?

Industrial Verification Examples

imageDid you know that there are over 30 industrial verification examples to browse on the official GENOA website?  In addition there are example videos of case models that demonstrate the capabilities of the GENOA modules. Find out more here! 
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