Global Local Analysis Overview
Global-Local analysis refers to the possibility of importing point loads or point constraints from a subdomain of a global shell (or solid) model and their application to a StressCheck detail analysis model. The following importation cases are addressed:
- Importation of point forces and moments per unit length (i.e. running loads) to be applied to the faces of solid elements or the edges of thin solids.
- Importation of point displacements and rotations to be applied to the faces of solid elements or the edges of thin solids.
- Importation of total load at a point (TLAP) to be applied to the faces of solid elements as bearing loads (TLAP-Bearing) or as tractions (TLAP-Traction)
StressCheck supports several formats for the importation of global loads and constraints. For example, Nastran point loads or constraints may be imported into the current project using File > Import and then selecting a *.bdf, .nas or .txt file.
To learn more about formatting and importation of point loads or constraints, refer to Importing Model Inputs. For a sample global-local analysis workflow, refer to StressCheck Tutorial: Sample Global-Local Workflow for a 3D Cracked Rib.
Point Running Loads
The functionality allows to import point running load information (forces and moments per unit length) from a global shell model into StressCheck, visualize these loads, and assign them to the faces of solid elements or the edges of shells. Using either the Fit-Auto or Fit-Manual methods, StressCheck calculates interpolated traction functions on those faces/edges, and incorporate the tractions into a load case for use in the finite element solution process.
Point Displacements & Rotations
The functionality allows for the visualization of the imported input displacements and rotations obtained from the solution of a global shell model, and their assignment to a set of selected solid elements faces or shell edges. Once the global displacements and rotations are assigned to elements using the Fit-Auto or Fit-Manual methods, interpolating functions are calculated for each displacement (Ux, Uy, Uz) and rotation (Rx, Ry, Rz) component. Both the displacements and rotations are understood to be in the global coordinate directions, and are positive when in the direction of the positive coordinate axes.
Once the data points are assigned to the local mesh, the quality of the continuous fitted functions over the imported data can be assessed by performing a quality check. The calculated displacement functions can be assigned to any constraint case.
Total Load at a Point (TLAP)
This functionality allows for the importation of total load at points (TLAPs) obtained from the solution of a global shell (or solid) model, and their assignment to a set of selected element faces or surface(s) of a solid model. These imported TLAPs may be uniformly scaled with the use of a user defined scaling parameter to asses the affects of overloading or load reversal scenarios. Two methods are available for assigning TLAPs: TLAP-Traction and TLAP-Bearing.