Sheet Metal Assembly Simulation with Approximate Forming Equilibrium

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Solution Overview

Problem

Existing methods for simulating and analyzing the assembly of sheet metal parts created by forming processes are computationally expensive, requiring repeated simulations that increase development time and resource usage.

Innovation Solution

A computer-implemented method that uses an approximate simulation to reduce computational load by determining strain and stress values based on reference geometry and material properties, allowing for efficient generation of an assembled part simulation model without the need for multiple forming simulations, and includes a scaling parameter to control material behavior and deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If repeated FEM simulations are executed to simulate forming and assembly processes, then simulation accuracy and reliability are improved, but computational cost and development time increase

Engineering Contradiction:
Improvesimulation accuracyVSAvoiddevelopment time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing forming process results (including stress, strain, and geometry data) in a database before the assembly simulation. This allows the assembly simulation to directly utilize these pre-computed data without re-executing the forming simulations, significantly reducing computational time while maintaining simulation accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a digital copy of the forming process results by generating a simulation model that replicates the forming outcomes (part geometry, material state, residual stresses) and stores it in a database. This copied data can be repeatedly used in assembly simulations without additional computational cost, resolving the contradiction between accuracy and time consumption.

Inventive Principle:
Principle #26Copying

2Manufacturing precision

If multiple forming simulations are performed to account for material behavior variations, then manufacturing precision is improved, but computational load increases

Engineering Contradiction:
Improveforming process accuracyVSAvoidcomputational load
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements parameter changes by introducing a scaling factor that modifies the elastic modulus in the assembly simulation based on forming process parameters (such as LDR - lateral draw ratio). This allows the simulation to account for material behavior variations without performing multiple separate forming simulations, reducing computational load while maintaining manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent pre-calculates forming process parameters (LDR, strain distribution, stress state) and stores them in the database before assembly simulation. These pre-computed parameters are then used to adjust material properties in the assembly simulation, eliminating the need for repeated forming simulations and reducing computational energy consumption.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If detailed FEM models with full material properties are used for assembly simulation, then simulation reliability is improved, but device complexity increases

Engineering Contradiction:
Improvesimulation reliabilityVSAvoidsimulation model complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the simulation process into two independent parts: (1) forming process simulation that generates detailed material state data, and (2) assembly simulation that utilizes this pre-computed data. By separating these processes and storing intermediate results in a database, the system maintains high reliability while reducing the complexity of the assembly simulation model itself.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary database that stores forming process results (geometry, stress, strain, material state) between the forming simulation and assembly simulation. This intermediary data structure allows the assembly simulation to access detailed material information without requiring the full complexity of the forming simulation model, thus reducing device complexity while maintaining reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method significantly reduces computational costs and development time while maintaining suitable results for simulating the assembly process, enabling quick iterations and optimization of part design.

Implementation Method 1

for the material points of the FEM mesh, based on the associated strain values and on material properties of the blank, determining associated stress values; based on the FEM mesh with the associated stress values, determining displacements of mesh points that bring the mesh into an equilibrium state with regard to the stresses

Methodology Applied
Scientific EffectStress-strain relationship: Elasticity

Data Source

PatentEP3929792A1Method for simulating and analysing an assembly of parts created by a forming process
Publication Date: 2021.12.29 NETABTAL MASCHEN
  • EP3929792A1 patent drawingFigure 1~3
  • EP3929792A1 patent drawingFigure 4~8
  • EP3929792A1 patent drawing

AI summary

A computer-implemented method serves for simulating and analysing an assembly of two or more formed sheet metal parts. It comprises simulating a forming process of each part by an approximate simulation (20), and then performing an assembly simulation (40). In order to allow for a quick iteration over different part geometries to assess the assembly, the approximate simulation (20) comprises • based on a reference geometry (10) of each part, estimating the deformation of a sheet metal blank required to attain the reference geometry (10); • based on this deformation, estimating stresses within the material of the formed part; • based on these stresses, estimating the shape of the formed part in which these stresses are in equilibrium, and using this shape as result (31) of the approximate simulation.