Time-Marching Simulation for Progressive Lancing in Sheet Metal
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Solution Overview
Problem
Existing computer-aided engineering simulations for sheet metal forming, particularly deep drawing, fail to accurately simulate progressive lancing operations due to distorted lancing routes and numerical errors caused by small finite elements.
Innovation Solution
A time-marching simulation method is implemented using a finite element analysis (FEA) model with a defined lancing route, where nodes and elements are adjusted and constrained to maintain proximity to the lancing route, allowing for a smooth and stable simulation by dividing elements and creating surrogate nodes, and a separation time schedule is used to manage nodal constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard FEA simulation is used for progressive lancing operation, then general forming process can be simulated, but lancing route becomes distorted and numerical errors occur due to small finite elements
Solution Approach 1:
The patent applies preliminary action by pre-defining the lancing route coordinates before the simulation begins. During the time-marching simulation, the lance position is continuously compared against these pre-defined coordinates to ensure the cut follows the intended path. This prevents route distortion by constraining the lancing operation to stay on the predetermined trajectory throughout the forming process.
Solution Approach 2:
The patent introduces an intermediary computational mechanism that acts as a mediator between the forming simulation and the lancing operation. This intermediary system continuously monitors element sizes near the lancing route and applies adaptive mesh refinement or numerical stabilization techniques when small elements are detected, preventing numerical errors while maintaining simulation accuracy.
2Device complexity
If conventional simulation methods are used, then computational simplicity is maintained, but mesh integrity is compromised due to distorted elements and numerical errors
Solution Approach 1:
The patent applies dynamics by implementing a time-marching simulation approach where the lancing operation progresses dynamically through the forming process. The simulation advances in incremental time steps, allowing the mesh to adapt and refine itself as the lancing front moves through the material. This dynamic approach maintains mesh integrity by continuously adjusting element configurations rather than using static, pre-defined meshes that would fail under large deformations.
Solution Approach 2:
The patent implements feedback mechanisms that continuously monitor mesh quality and element dimensions during the simulation. When small or distorted elements are detected near the lancing route, the system automatically triggers mesh refinement or adjusts numerical parameters to prevent errors. This feedback loop maintains mesh integrity without requiring excessive manual intervention or overly complex initial setup.
3Adaptability or versatility
If progressive lancing is simulated with standard FEA, then the forming process can be modeled, but the lancing route deviates from the intended smooth curve due to element deformation
Solution Approach 1:
The patent applies universality by creating a multi-functional simulation framework that simultaneously handles both the sheet metal forming process and the progressive lancing operation within a single computational model. The simulation integrates punch-die contact mechanics, material deformation, and lancing cut propagation, allowing all these processes to interact realistically while maintaining the intended lancing route geometry through coordinate-based constraints.
Data Source
AI summary
Systems and methods of conducting a time-marching simulation of manufacturing a sheet metal part that requires progressive lancing operation (PLO) are disclosed. The time-marching simulation is conducted with a connection-separation scheme for nodes along the lancing route to ensure a smooth timely separation of a lancing cut. The scheme includes creating a set of surrogate lancing route nodes by duplicating nodal coordinates of the existed nodes located along the lancing route. Nodal constraints to initially link together the existed nodes and the corresponding surrogate nodes are then created. The nodal constraint is removed in accordance with a separation time schedule established using start and end locations of the lancing route and corresponding start and end time for making the lancing cut. The nodal constraints can also be removed based on the zones of the lancing route defined by a user.