The NASCRAC™ Software

The NASCRAC™ Software is a general-purpose fracture mechanics tool. Originally developed by Failure Analysis Associates (now Exponent) for NASA’s Marshall Space Flight Center, the software is available by license from Exponent, along with support services. The NASCRAC Software is a versatile, user-oriented tool that can be used to solve linear and nonlinear fracture mechanics problems that frequently arise in industries such as aerospace, petro-chemical, power generation, defense, and transportation. Capabilities include evaluation of stress intensity factors, J-integrals, fatigue-crack growth, creep-crack growth, and stress corrosion cracking.

The NASCRAC™ Software is a trademark of Exponent, Inc.

A key aspect of the NASCRAC Software is its broad range of crack configurations for which stress intensity factor, K, solutions are provided. Extensive use of influence-function solutions allows analysis of cracks under arbitrary spatial stress distributions. In the rare instance where existing crack geometry solutions are not suitable, capabilities are included for generating new influence functions for planar bodies.

The NASCRAC Software is not a stress analysis program; however, stress is an important input to any fracture mechanics analysis. Stress input can be obtained from a variety of sources, ranging from hand calculations to finite element analysis. A key feature of the NASCRAC program is that it requires only the stress in the uncracked body; therefore, the stress analysis performed to obtain input stress does not have to (and should not) include the crack. The K and J-integral solutions in the NASCRAC program account for the effect of the presence of the crack on the input stress.

The NASCRAC Software employs crack growth analysis methods based on linear elastic fracture mechanics and utilizes the crack-tip stress intensity factor as the measure of crack driving force. However, the software includes a number of J-integral solutions for analysis of cracks under elastic-plastic conditions. Material parameters related to subcritical and critical crack growth are included in the NASCRAC Software materials library for a wide range of materials, or they can be entered by the user based on literature data or data measured experimentally. The NASCRAC Software is particularly useful for analysis of fatigue crack growth due to cyclic loading and therefore concentrates on opening-mode (Mode I) loading.

Technical support for The NASCRAC™ Software is provided by engineers at Exponent who have extensive education and experience in fracture mechanics, failure analysis, and failure prevention. Hands-on training seminars can be arranged either at Exponent or at your site.

  • A NASCRAC Software tear sheet is available here.
  • A summary of the crack solution library in the NASCRAC Software is available here

Related Exponent Services Include:

  • Analysis of the impact of cracks on mechanical components and structures subjected to static and dynamic loading
  • Life prediction analysis of component and structures subjected to cyclic loading, corrosive environments, or high temperatures in the creep regime
  • Fitness-for-service analysis 
  • Fatigue and fracture assessments of transmission pipelines and process piping 
  • Analysis of equipment in electric power generation facilities 
  • Mechanical failure analysis 
  • Analysis of ground transportation structures
  • Analysis of aerospace structures
  • Analysis of ship and offshore structures
  • Mechanical design reviews 
  • Asset management and integrity assessment 
  • Reliability assessments for components subject to cracking