Using Forming Simulation Data as Input for Fatigue and Other Thermo-Mechanical Analyses
Introduction
In recent years, the demand for higher-performing products has grown significantly. To meet these requirements—while also reducing production costs and lead times—companies have placed greater emphasis on “front loading.” In this approach, simulations play a pivotal role in identifying and resolving potential issues before reaching the real-world manufacturing stage.
One successful example of this kind of integration is the collaboration between Walmaz and a renowned international water pump manufacturer. By applying data from AutoForm simulation as input for subsequent analyses in other software, they established a streamlined digital workflow.
The company: Walmaz
Founded in 1973 and headquartered in San Giorgio delle Pertiche, Italy, Walmaz specializes in designing and manufacturing hand-transfer, progressive, and automatic-transfer tools for cold cutting and forming of sheet metals. Their products primarily serve the automotive and white goods sectors.
Walmaz supports its customers from the initial phase of tool design, also providing deep-drawing simulations of the production cycle. These simulations come with analysis reports and recommendations on necessary modifications to ensure part feasibility. Additionally, Walmaz has presses available to stamp parts for customers requesting this service.
During the co-design phase, Walmaz collaborates closely with the customer to arrive at a design optimized for their production needs, while also ensuring high quality and custom-purpose solutions. Their technical team uses up-to-date 2D and 3D software to study tooling in close partnership with customers, always seeking innovative solutions.
With advanced machinery in their toolshop, Walmaz can produce tool components in-house, then assemble and test the complete production line. Tool tryouts are conducted on dedicated presses, and customers receive stamped sample parts along with dimensional reports. In a nearby facility, Walmaz also has presses to complete stamping work if needed.
Fig. 1: Example of a simulation report created by the Walmaz team
Current Simulation Processes vs. Emerging Trends in the Home Appliances Industry
At present, stamping simulations are typically treated as a separate process from impact or drop simulations and fatigue-resistance analyses. Typically, the latter are performed using initial data from CAD, without considering any prior deformation history (in terms of thickness variations, residual stresses, and springback effects).
In other words, the information flow stops after stamping simulations. This leads to subsequent analyses that are only partially realistic and can prompt engineers to make decisions based on incomplete or inaccurate results.
To overcome this limitation, the current trend is to fully digitalize the design workflow. The demand for products that perform optimally on the first attempt drives the need for simulations that are increasingly faithful to real-world conditions. Designers must build a seamless process—from material testing for virtual characterization cards to digital process design, stamping simulations, and thermo-mechanical, impact, fatigue resistance, and appliance daily usage CAE analyses.
With this goal in mind, AutoForm gives users the option to export simulation results in different formats, allowing them to serve as input data for subsequent analyses. This approach makes it possible to transfer thickness/thinning data, residual stresses, and mesh information, resulting in more precise and comprehensive simulation outcomes. The export can be done in widely used formats (such as CSV) or with specific setups (Dyna, Pam, VRML), together with an attached mesh in STL/Nastran/AF formats.
The advantages are clear: product geometries and performance can be refined while still in the virtual environment, thereby reducing development costs and lead time.
Focusing on one specific case, the aim was to perform a fatigue resistance analysis on a component that is mounted on a water pump—a part known to experience frequent failures. The complete production process was engineered using AutoForm stamping simulations. From the validated process (which formed the basis for milling and tool assembly), a Dyna data file was exported and fed into a commonly used multi-purpose simulation software (for CFD, Mechanical, etc.).
Fig. 2: Critical thinning area: The part is not torn, but this zone is critical in terms of fatigue failure after assembly. Fatigue resistance simulations that use nominal thickness CAD data do not reveal any problems, while those based on AutoForm-derived data highlight an issue in this area.
Certain critical points already visible in the forming simulation turned out to be precisely where fatigue began. Using nominal CAD data (with constant thickness and no deformation history) in a mechanical simulation didn’t point out those vulnerabilities. However, by incorporating forming results, engineers could see the issues and explore possible solutions with all the important data at their disposal.
Possible Long-Term Expansions & Conclusions
Once this type of simulation process becomes fully established and integrated into the companies’ workflows, the next step toward a complete digital workflow will be simulating the whole appliance assembly within AutoForm Assembly. This approach makes it possible to export data for parts that are constrained to one another—data that can be immensely useful in subsequent simulations (for example, structural deformation simulations).
Exchanging data among different simulation software solutions is a practice that yields superior “digital products”, which can then be realized as better, higher-performing “real products,” supported by an optimized production process in terms of cost and lead time.
Special thanks to the Walmaz Team for sharing their expertise for this post!
