The challenge car makers face every day is designing cars to withstand all possible use cases during their entire product lifecycle. To support these investigations, Stellantis uses nCode DesignLife software within their development processes for fatigue analysis.
The challenge car makers face every day is designing cars to withstand all possible use cases during their entire product lifecycle. Therefore, significant effort is required to predict and test the fatigue life of vehicle systems and components in order to improve quality, prevent failures, and lower warranty costs.
After an extensive evaluation of nCode DesignLife, in which the software was compared to Stellantis-Fatig, Stellantis selected nCode to handle fatigue analysis in its powertrain and suspension development areas. Along with scripting and interface features available in nCode, Stellantis engineers appreciated its ability to import finite element results from Abaqus (Dassault Systèmes) and MSC Nastran (MSC.Software). nCode DesignLife is applied on volume parts for powertrain development and on sheet metal parts within the suspension, including investigations on seam welds as well as spot welds. HBK, developer of nCode DesignLife, provided Stellantis engineers with training and support throughout the deployment phase and worked with Stellantis to configure software to their specified needs.
Stellantis has reached a milestone in their development process by using nCode DesignLife for fatigue evaluations. By implementing new criteria for fatigue analysis, Stellantis is now able to develop new methodologies, decrease physical tests, and achieve more accurate results. This will lead to more cost-efficient and less time-consuming development processes.
Stellantis is a world-class automobile manufacturer, offering 14 brands, with operations in 150 countries, Stellantis demonstrates a commitment to innovation in the areas of safety and environmental protection in order to develop and build cars that meet the high expectations of Peugeot and Citroën customers around the world.
In the past, Stellantis powertrain and suspension used its in-house fatigue code, Stellantis-Fatig, which is based on the Dang Van criterion, a method to predict endurance limits under complex loading situations. The Dang Van criterion is classified as a ‘micro-structural’ method because it considers stresses and crack initiation at the local level. Unlike other methods, output from the analysis is always expressed as a safety factor as opposed to fatigue life.
To further streamline its development process, Stellantis looked for fatigue software packages that included their historical Dang Van criterion approach for validating fatigue resistance and other beneficial features such as proven fatigue approaches, an advanced user interface, and the ability to prototype new methods via scripting. Since all of Stellantis validations for fatigue resistance are based on the Dang Van criterion, it was essential that any alternative software tool covered this approach in order to achieve time and cost savings in the development process.
After an extensive evaluation of nCode DesignLife, in which the software was compared to Stellantis-Fatig, Stellantis selected nCode to handle fatigue analysis in its powertrain and suspension development areas. Along with scripting and interface features available in nCode, Stellantis engineers appreciated its ability to import finite element results from Abaqus (Dassault Systèmes) and MSC Nastran (MSC.Software). nCode DesignLife is applied on volume parts for powertrain development and on sheet metal parts within the suspension, including investigations on seam welds as well as spot welds. HBK, developer of nCode DesignLife, provided Stellantis engineers with training and support throughout the deployment phase and worked with Stellantis to configure software to their specified needs.
The objective of a fatigue life investigation is to evaluate the fatigue strength of parts or components. If a calculation shows that the fatigue strength cannot be ensured, the geometry of the part has to be modified until it meets the criteria. A typical investigation consists of loading results (stresses) from a finite element analysis (i.e. from Abaqus or Nastran), applying certain load conditions, and performing the fatigue analysis itself (with Dang Van criterion or other). The results, such as contour plots of danger factors, are then displayed. The results of the fatigue analysis are written into a file that can be reloaded into Stellantis standard post-processing software, HyperView from Altair Engineering.
The following example showcases a fatigue evaluation of an engine cradle. A finite element analysis has been performed with Abaqus. Several loads case describing a loading cycle on the cradle have been applied. In the next step, the finite element results are loaded into nCode DesignLife (via the FE Input Glyph) and have been sent to the fatigue analysis Glyph (Dang Van). The user then defines the material parameters according to the Dang Van criterion (parameters HSS and TAFE) and the results are displayed on a FE Display Glyph and written to a file. This analysis can be performed on both the metal sheets (Fig. 3) and the spot welds (Fig. 4).
To handle spot welds (ESW), HBK implemented a specific treatment in the Dang Van Glyph as requested by Stellantis. This customized development step enables Stellantis to perform the same type of calculation as with Stellantis-Fatig. The FE model of the ESWs uses beams, and in this case, the input data to nCode DesignLife (FE input Glyph) are the forces expressed on the nodes of the beams. The specific treatment implemented in nCode DesignLife allows these forces to be converted into stresses around the ESW, and then the Dang Van criterion can be calculated.
Stellantis has reached a milestone in their development process by using nCode DesignLife for fatigue evaluations. By implementing new criteria for fatigue analysis, Stellantis is now able to develop new methodologies, decrease physical tests, and achieve more accurate results. This will lead to more cost-efficient and less time-consuming development processes.
Additionally, Stellantis engineers are able to perform more numerical investigations to better determine any design changes needed to meet targeted component performance. They are also able to handle evaluations of varying size and scope, resulting in analyses that are more robust, predictive, and adaptable to specifications required for different applications (vibration fatigue, composite materials…). Stellantis plans to replace Stellantis-Fatig with nCode DesignLife in all divisions performing fatigue evaluations for applications ranging from powertrain to the entire body of the vehicle.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
This will bring together HBM, Brüel & Kjær, nCode, ReliaSoft, and Discom brands, helping you innovate faster for a cleaner, healthier, and more productive world.
