BEASY Fatigue & Crack Growth

beasy fatigue  crack growthclutch plate smallBEASY Crack modelling technologies provides quick and accurate tools to:

Add cracks to models

Predict stress intensity factors

Predict crack growth rate and direction

Predict residual strength

The BEASY Fracture workbench simplifies and automates the difficult task of creating a mesh to represent a crack in a complex 3D model. The user selects the type and shape of crack from a library of crack shapes, identify its location on the model and the software does the rest.

Automatic Crack Growth

The BEASY Crack Growth Wizard not only allows users to insert cracks in structural models but allows
them to grow the cracks under fatigue loading as well.  The helpful tools available with the BEASY SIF
Calculator are also available with this module. However many additional features, specific to supporting fatigue crack growth analysis, are also available.  A variety of fatigue crack growth models, including the simple Paris Law, Walker-Change, and NASGRO can be selected. BEASY is fully integrated with the NASGRO material database and the user can select the required material from a series of dropdown menus.  There is full support for using load spectrum (LSP) data to drive the crack growth process and a range of LSP formats are available; including standard block, sequential loading, and multi-axial load spectrum formats.

Automatic Crack Growth

The BEASY Fatigue & Crack Growth module has a number of advanced features not available in other crack growth software and these can be used to perform crack growth simulation in residual stress fields, apply pressure directly to the crack face for leak-before-burst type analysis, and investigate crack closure using sophisticated crack surface contact algorithms.

The SIF data and crack growth rate data can be quickly processed using graphing functions available in the Crack Growth Wizard or manipulated using BEASY's Crack Master templates to display fatigue crack growth results in a series of charts and summary data tables using specially designed Excel macros.  This data is also output in tabular formats for easy import into common desktop software.

SIF Graphs

Advanced Fracture Analysis

advanced fracture analysisBEASY is based on Boundary Element Technology which has significant benefits when solving fracture mechanics applications. The technology can more accurately represent the high stress fields near the crack front and the surface only mesh simplifies the tasks associated with crack modelling and mesh generation as the crack grows. The software supports crack modelling in two dimensional and three dimensional structures. Although BEASY crack models are based on boundary element technology it fully integrates with Finite Element Models.

The BEASY Advanced Fracture Analysis module supports a range of processes often used in conjunction with the BEASY Crack Growth module. Functionality exists to modify the automatic crack growth process in cases where a non-planar crack may grow into an area of very complex geometry.  It is possible to adjust the crack growth increment and crack mesh refinement with simple to use menus and then automatically re-launch the analysis job. The Fatigue Life Calculator is another very useful option and provides the capability to reprocess SIF data using different material properties or load spectrums in order to predict the effect on structural life predictions.  This is a fast and easy post-processing option that does not require the computational effort required to compute new SIF values.

Stress Intensity Factors

BEASY supports mixed mode crack growth and computes Ki, Kii and Kiii. There are options to select different methods of computing the SIF including J Integral and Crack Opening Displacement (COD).

Residual Stresses

Crack growth through residual stress fields can be simulated. The residual stress fields can be obtained from FEM models.

Contact Simulation

fretting case study largeBEASY provides a powerful modelling tool to predict the critical stresses and slip motion of components in contact including closed crack faces to provide accurate prediction of contact stresses, slip and wear data prediction. BEASY's nonlinear contact algorithm automatically computes the change in position of the contact surfaces and the resulting stress redistribution.

Predicting the behaviour of cracks under compressive loading provides an important analytical component and is helpful in understanding the fretting fatigue behaviour of fracture critical components.

The constraint based contact algorithm driving the BEASY analysis computes the appropriate surface contact conditions (e.g., open, closed, sliding) and enforces this condition during the iterative solution phase. Products can be subjected to loading sequences to simulate the in service conditions. Load transfer characteristics as well as detailed stress history are predicted.

Predicting the behaviour of cracks under compressive loading provides an important analytical component and is helpful in understanding the fretting fatigue behaviour of fracture critical components. 

Fatigue Criteria

Fatigue Crack Growth Criteria

The crack growth laws supported include:

  • Paris
  • Forman
  • Rhodes
  • NASGRO (2, 3, 4, 5)
  • Walker Chang
  • Vasudevan
  • Unigrow
  • Navarro (short cracks)
  • User defined tabulated da/dn

Retardation Models

Retardation Models

Retardation models can be used with selected growth equations to represent the effect of plasticity in the model.

  • Generalised Willenborg
  • Modified Generalised Willenborg
  • Walker Chang

Direction Criteria

Crack Growth Direction Criteria

  • Maximum Principal Stress (2D only)
  • Minimum Strain Energy Density
  • Multi-axiality (Q Plane) searching
  • Mode 1 growth

Database

Materials Database

  • NASGRO 2/3 databases (Over 360 materials are represented)
  • Ability to link to the NASGRO 4 & 5 database
  • Alternatively users can define their own material properties

Modeling

Crack Modelling

  • Single or multiple cracks
  • Embedded or edge cracks
  • Flat or curved cracks can be used
  • User defined cracks can be added to models
  • Crack used in BEASY are defined using dual boundary elements

Results

Fatigue Crack Growth Results

  • Stress Intensity Factors
  • Crack and model deformation
  • Crack and model stress field
  • Crack propagation path
  • Crack growth rate

Properties

Material Properties

  • Isotropic, linear elastic for 3D, 2D and axisymmetric
  • Isotropic, orthotropic and anisotropic linear elastic for 2D and 3D

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