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CBAR, CROD Opti. |
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CBAR, CROD Opti. |
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CBAR, CROD Opti. |
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CBAR, CROD Opti. |
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This utility may be used to setup size optimization for multiple CBAR or CROD elements.
| 1. | Click CROD, CBAR Opti. |
You are prompted to select 1-D elements for topological optimization.
| 2. | Select elements. |
| 3. | Select PBAR or PROD. |
A new PBAR or PROD property is created for each 1-D element selected. These properties are called DPROP#.
A size design variable is created for each 1-D element selected.
| 4. | Input the initial value and upper and lower limits for this variable. |
The design variables are called DV#. These design variables represent the cross-sectional area of each 1-D element.
A DVPREL1 card is created linking each of the DV#’s to the cross-sectional area of each DPROP# card. These are called DX#.
For simplicity, we assume the 1-D elements have solid, circular cross-sections. Two equations are created to calculate the I and J values if the PBAR property type is chosen:
| a) | Equation for Ix and Iy values : Y(X1) = 0.0796*X1**2 |
| b) | Equation for J values: Y(X1) = 0.1592*X1**2 |
A DVPREL2 card is created for the I1 value of each DPROP#, referencing equation (a) and the appropriate design variable. These are named DA#.
A 2nd DVPREL2 card is created for the I2 value of each DPROP#, referencing equation (a) and the appropriate design variable. These are named DB#.
A 3rd DVPERL2 card is created for the J value of each DPROP#, referencing equation (b) and the appropriate design variable. These are named DC#.
A 3rd equation is created to calculate the regional volume fraction for all DPROP# properties:
Y(X1,Xi,....,Xn) = (X1+Xi+....+Xn)/(X1o+Xio+...+Xno)
where Xi is the value of DVi, and where Xio is initial value of Xi.
A function response, called BVFRAC, is generated using this equation and referencing all design variables.