Table of Contents
Linear elastostatics
Computation schema
Computation steps
1. Process the mesh
The input data is written into the text file name.i1.
All element types can be used with the exception of the sandwich and thermal resistance which are designed for heat transfer computations only.
| Program | RMD2 (2-D problem) / RMD3 (3-D problem) |
|---|---|
| Inputs | name.i1, alternatively name.NOD and name.ELE |
| Protocol | name.o1 |
| Outputs | binary files |
| Details | Computation overview, Mesh / Reference Manual: Inputs, Element Library, Input Syntax |
2. Process the material properties and boundary conditions
The input data is written into the text file name.i2.
A temperature or displacement field from a previous computation can be loaded directly from the binary file name.TEM or name.SOL, respectively.
| Program | RPD2 (2-D problem) / RPD3 (3-D problem) |
|---|---|
| Inputs | name.i2, binary files from the previous step, name.TEM (optionally), name.SOL (optionally) |
| Protocol | name.o2 |
| Outputs | binary files |
| Details | Computation overview, Material properties, Support, Loading / Reference Manual: Inputs, Quantities, Input Syntax |
3. Calculate the stiffness matrices and right-hand sides
The input data is written into the text file name.i3.
Usually, only the key of restart $\mathtt{KREST}=1$ is specified, which means the assembly of the stiffness matrices of all elements and the right-hand side vectors for all load cases processed in the previous step.
It is recommended to check the sums of forces and moments in the protocol name.o3.
| Program | SRH2 (2-D problem) / SRH3 (3-D problem) |
|---|---|
| Inputs | name.i3, binary files from the previous steps |
| Protocol | name.o3 |
| Outputs | binary files |
| Details | Computation overview / Reference Manual: Inputs |
4. Solve the equations
The input data is written into the text file name.i4.
Usually, only the key of restart $\mathtt{KREST}=1$ is specified, which means the factorization of the global stiffness matrix and back substitution for all right-hand side vectors processed in the previous step.
If the solution is terminated prematurely due to a zero or negative pivot, it means that the body was allowed to move as a rigid unit, i.e., the boundary conditions were specified incorrectly.
| Program | FEFS (2-D / 3-D problem) |
|---|---|
| Inputs | name.i4, binary files from the previous steps |
| Protocol | name.o4 |
| Outputs | binary files (the solution is in the file name.SOL) |
| Details | Computation overview / Reference Manual: Inputs |
5. Calculate the strains and stresses
The input data is written into the text file name.i5, where the key of problem type is $\mathtt{KPROB}=0$.
It is recommended to check the equilibrium of the forces and reactions in the protocol name.o5 which represents the criterion for the accuracy of the solution.
| Program | STR2 (2-D problem) / STR3 (3-D problem) |
|---|---|
| Inputs | name.i5, binary files from the previous steps |
| Protocol | name.o5 |
| Outputs | name.STR (optionally), name.STB (optionally) |
| Details | Computation overview / Reference Manual: Inputs |