nCode DesignLife Product Options
nCode DesignLife is the next generation CAE fatigue and durability analysis tool that works with all leading FE codes and produces realistic predictions of fatigue hotspots and fatigue life. DesignLife shares the nCode GlyphWorks architecture – providing an unparalleled integration of test and CAE data. DesignLife can be purchased separately or together with GlyphWorks.
DesignLife's core functionality includes:
Virtual Strain Gauge – is a standard feature of DesignLife that provides a uniquely powerful way of correlating test with finite element results. Graphically position and orient many single or rosette gauges on your finite models as a post-processing step. Time histories due to applied loads can then be extracted for direct correlation with measured data.
Users can reconstruct load histories from measured strain histories and unit load FEA stresses with DesignLife’s Virtual Strain Gauge at no additional cost.
Schedule Create - lets the user build and process multiple cases that model a duty cycle. Through an intuitive interface, Schedule Create makes it easy to create a complete durability schedule.
Signal Processing – includes GlyphWorks Fundamentals functionality for basic data manipulation, analysis and visualization.
Materials Manager – enables materials data to be added, edited and plotted. A default database with fatigue properties for many commonly used materials is also provided.
Python Scripting – unique capability that enables Python scripting to be used to extend existing analysis capabilities rather than needing to code fatigue analysis from scratch. Perfect for proprietary methods or research projects.
Crack Growth - provides a complete fracture mechanics capability using industry standard methodologies for specified locations on an FE model. Built-in growth laws include NASGRO, Forman, Paris, Walker, and more. Select from a provided library of geometries or supply custom stress intensity factors.
Applicable to a wide range of problems including low-cycle fatigue with the local elastic-plastic strain controls the fatigue life. The standard E-N method uses the Coffin-Manson-Basquin formula, defining the relationship between strain amplitude εª and the number of cycles to failure Nf. Material models can also be defined using general look-up curves. This enables the ability to interpolate multiple material data curves for factors such as mean stress or temperature.
- Standard EN
- EN mean multi-curve
- EN R-ratio multi-curve
- EN temperature multi-curve
Multiaxial Damage models
- Wang Brown
- Wang Brown with Mean
Mean stress corrections
- Smith Watson Topper
- Interpolate multiple curves
- 3D Multiaxial
The primary of the Stress-Life (SN) method is high-cycle fatigue (long lives) where nominal stress controls the fatigue life. Includes the ability to interpolate multiple material data curves for factors such as mean stress or temperature. Further options are also provided to account for stress gradients and surface finishes. Python scripting is also available for defining custom fatigue methods and material models.
- Standard SN
- SN Mean multi-curve
- SN R-ratio multi-curve
- SN Haigh multi-curve
- SN Temperature multi-curve
- Bastenaire SN
- Custom SN using Python scripting
Mean stress corrections
- FKM Guidelines
- Interpolate multiple curves
Stress gradient corrections
- FKM Guidelines
- User defined
Dang Van is a multi-axial fatigue limit criterion and is a method of predicting the endurance limit under complex loading situations. The output from the analysis is expressed as a safety factor and not a fatigue life.
- Output from the analysis is always expressed as a safety factor not a fatigue life
- Specific material parameters are calculated from tensile and torsion tests
- Primary application for engine and powertrain-type applications where there are very large numbers of loading cycles of combined loading such as bending and torsion producing multi-axial stress states
This option enables the fatigue analysis of spot welds in thin sheets. The approach is based on the LBF method (see SAE paper 950711) and is well-suited to vehicle structure applications.
- Spot welds are modelled by stiff beam elements (e.g. NASTRAN CBAR) as supported by many leading FE pre-processors.
- Also supported – CWELD, ACM formulations using solid elements.
- Cross sectional forces and moments are used to calculate structural stress around the edge of the weld spot.
- Life calculations are made around spot weld using linear damage summation and reporting worst case.
- Python scripting is also available for modelling other jointing methods such as rivets or bolts.
This option enables the fatigue analysis of seam welded joints including fillet, overlap, and laser welded joints. The method is based on the approach developed by Volvo (see also SAE paper 982311) and validated through years of use on vehicle chassis and body development projects. Stresses can either be taken from FE models (shell or solid elements) or calculated from grid point forces or displacements at the weld.
- Automated FE data processing makes job set-up quick and simple.
- Weld toe and root failure
- Thickness correction
- Mean stress effects
- BS7608 welding standard is also supported together with require material curves.
Vibration Fatigue enables the simulation of vibration shaker tests driven by random (PSD) or swept-sine loading. It provides the capability to predict fatigue in the frequency domain and it is more realistic and efficient than time-domain analysis for many applications with random loading such a wind and wave loads.
- FE models are solved for frequency response analysis and the vibration loading is defined in DesignLife.
- Include static offset case and complete duty cycles of combined loading.
- Perfect add-on product is Accelerated Testing to derive a tailored test profile from multiple loading spectra.
Provides solvers for high temperature fatigue and creep by using stress and temperature results from finite element simulations. Applications include components that are both mechanically and thermally loaded such as vehicle exhaust systems and manifolds.
High temperature fatigue methods:
- Chaboche method is a stress-life approach that uses stresses from FE and either a constant or cycle-by-cycle temperature correction.
- ChabocheTransient method accounts for temperature by normalizing the stress history prior to cycle counting. This method has particular application for finite element analysis where the temperature and stress variation is closely correlated, for example where a transient visco-elasto-plastic analysis has been performed.
Creep analysis methods:
- Chaboche and Larson-Miller creep methods are available.
- The damage from fatigue and creep can be directly summed. The required material data is derived from standard constant temperature fatigue and creep tests.
Short Fibre Composite
This option uses stress-life fatigue calculations for anisotropic materials such as glass fibre filled thermoplastics. The stress tensor for each layer and section integration point through the thickness is read by DesignLife from FE results. The material orientation tensor describing the “fibre share” at each calculation point is provided by mapping a manufacturing simulation to the finite element model. This orientation tensor can be read from the results file or supplied from an ASCII file.
- Stresses can be from regular FE results or from calculations with a composite material model from DIGIMAT. In this case, the averaged matrix and fibre stresses will be available in addition to the overall composite (macro) stresses.
- Primarily aimed at the fatigue analysis of short fibre composites, it can also be applied to laminar composites where failure modes due to interlaminar stresses can be ignored.
- A set of one or more SN curves based on fibre share is used to determine the SN curve for each calculation point and orientation.
- Stress combination methods are provided for critical plane and absolute maximum principal stress.
This option enables durability calculations on adhesive joints in metallic structures. nCode DesignLife uses a fracture mechanics-based method to assess which joints in the structure are most critically loaded.
- Adhesive bonds are modeled with beam elements and grid point forces are used to determine line forces and moments at the edge of the glued flange.
- Approximate calculations of the strain energy release rate are made at the edge of the adhesive and, by comparison to the crack growth threshold, a safety factor is calculated.
- The theoretical basis of the method was developed by the Volvo Group and the testing and software implementation was carried out as part of a collaborative research project with partners including Jaguar Land Rover, Coventry University and Warwick University.