Determination of a model of a geometry of a metal sheet forming stage

A method for determining a model of a geometry of a forming stage (1) in a computer-aided design (CAD)-system, comprising, for computing an edge line (3) of a forming stage (1) in an initial condition before a forming process from the geometry of the edge line (3) in a result condition after the forming process, wherein the forming stage (1) is a deep-draw stage, or the forming stage (1) is a subsequent stage after a deep draw stage, the following sequential steps:

• generating a computation mesh, for describing a geometry of the forming stage in the result condition;
• initialising condition parameters for at least one of a multitude of mesh elements and mesh nodes of the forming stage (1) in the result condition;
• mapping the computation mesh onto a geometry of the forming stage (1) in the initial condition;
• computing condition parameters changed according to the mapping, in the mapped mesh elements and/or mesh nodes;
• determining a balanced computation mesh for the initial condition by way of shifting mesh elements or mesh nodes, until element forces of the mesh and external forces are at least approximately in equilibrium;
• and
• extracting the edge line (3) of the forming stage (1) in the initial condition from the balanced computation mesh.

A data processing system for determining a model of a geometry of forming stage in a computer-aided design (CAD)-system, wherein the data processing system comprises means for carrying out the following steps:

• defining an operator for describing a relation between the first geometry object and a second geometry object, which describes the forming stage in a second condition, wherein the operator comprises parameters for describing at least one forming step of the forming stage (1);
• computing the second geometry object from the first geometry object by way of carrying out an operator method, which by way of the geometry of the forming stage (1) in the first condition, by way of the parameters of the at least one forming step, and by way of a physical simulation of the at least one forming step, determines a geometry of the forming stage (1) in the second condition;
• and
• producing a computer model in the working memory region of the CAD-system computer corresponding to the forming stage in the second condition,
• wherein the operator method computes an edge line of the forming stage in the first condition before a forming process, from the geometry of the edge line (3) in the second condition after the forming process, and the operator method comprises the following sequential steps:
• generating a computation mesh, for describing a geometry of the forming stage in the second condition;
• initialising condition parameters for at least one of a multitude of mesh elements and mesh nodes of the forming stage (1) in the second condition;
• mapping the computation mesh onto a geometry of the forming stage (1) in the first condition;
• computing condition parameters changed according to the mapping, in the mapped mesh elements and/or mesh nodes;
• determining a balanced computation mesh for the first condition by way of shifting mesh elements or mesh nodes, until element forces of the mesh and external forces are at least approximately in equilibrium;
• extraction of the edge line (3) of the forming stage (1) in the first condition from the balanced computation mesh.

A computer-readable medium on which a computer program code is stored, the computer program being for determining a model of a geometry of a forming stage in a computer-aided design (CAD) system, and which is loaded onto and carried out in a data processing unit, and which on execution, carries out the following method steps:

• defining an operator for describing a relation between the first geometry object and a second geometry object, which describes the forming stage in a second condition, wherein the operator comprises parameters for describing at least one forming step of the forming stage (1);
• computing the second geometry object from the first geometry object by way of carrying out an operator method, which by way of the geometry of the forming stage (1) in the first condition, by way of the parameters of the at least one forming step, and by way of a physical simulation of the at least one forming step, determines a geometry of the forming stage (1) in the second condition;
• and
• producing a computer model in the working memory region of the CAD-system computer corresponding to the forming stage in the second condition
• wherein the operator method computes an edge line of the forming stage in the first condition before a forming process, from the geometry of the edge line (3) in the second condition after the forming process, and the operator method comprises the following sequential steps:
• generating a computation mesh, for describing a geometry of the forming stage in the second condition;
• initialising condition parameters for at least one of a multitude of mesh elements and mesh nodes of the forming stage (1) in the second condition;
• mapping the computation mesh onto a geometry of the forming stage (1) in the first condition;
• computing condition parameters changed according to the mapping, in the mapped mesh elements and/or mesh nodes;
• determining a balanced computation mesh for the first condition by way of shifting mesh elements or mesh nodes, until element forces of the mesh and external forces are at least approximately in equilibrium;
• extraction of the edge line (3) of the forming stage (1) in the first condition from the balanced computation mesh.

A computer readable medium on which a computer program code is stored, the computer program being for determining a model of a geometry of a forming stage in a computer-aided design (CAD)-system, and which may be loaded onto and carried out in a data processing unit, and which on execution carries out the following method steps sequentially:

• generating a computation mesh, for describing a geometry of a deep draw forming stage in the result condition;
• initialising condition parameters for at least one of a multitude of mesh elements and mesh nodes of the forming stage (1) in the result condition;
• mapping the computation mesh onto a geometry of the deep draw forming stage (1) in the initial condition;
• computing condition parameters changed according to the mapping, in the mapped mesh elements and/or mesh nodes;
• determining a balanced computation mesh for the initial condition by way of shifting mesh elements or mesh nodes, until element forces of the mesh and external forces are at least approximately in equilibrium;
• and
• extracting the edge line (3) of the deep draw forming stage (1) in the initial condition from the balanced computation mesh.