6d. Algor Design Optimization

Design Optimization

This report will explore the process of design optimization. In the first part, we set up the structural analysis with the thickness of surface 500mm which should be more than the need. In the second part, we will process the design optimization to figure the minimum thickness of the surface based the objective of limit of stress and minimum volume (material used).


Please refer to the surface structure_Tokyo Cathedral report. The following are the input information for the analysis in this part.

Element definition

Setting the thickness of material as 500mm


Setting the material as Concrete (Medium Strength)

Boundary condition

Setting the edges at the bottom of the model as ‘Fixed’ boundary.


Setting the wind load from one side of the model with 0.002 N/ sqmm

Select the whole part and apply the vertical surface variable load as 0.005 N/sq mm

Setting the gravity load in ‘Analysis Type’


Maximum displacement: 11.28277mm

Maximum strain: 0.0001855196

Maximum stress: 3.898837N/sq mm

By clicking ‘Tools’ in menu bar and clicking ‘Weight and Center of Gravity’, we can review the volume and weight of the model.

Volume: 2.2140E+12 cubic mm

Weight: 5.2250E+07 N


Stress (3.898837N/sq mm) is much lower than the yield strength of concrete. Therefore, there is a potential to use less material.

With the function of ‘Design optimization’ in Algor, we can optimize our design (plate element thickness, cross section dimension etc) based on the objective based on the objective (minimize the stress, minimize the volume, deflection, etc.)

The following part will discuss the procedure of setting up ‘Design optimization’ in Algor and figure out the minimum thickness of the surface based the objective of limit of stress and minimum volume (material used).


1 Defining ‘Deign Variable’

After the analysis in part 1, we go back to the page of ‘FEA Editor’ and double click the ‘Element Definition’. Check the box of ‘Design variable’. Press ‘OK’

Click ‘Tools’ in the menu bar and click ‘Optimize’. In the page of ‘Design Variable’, The current value is the material defined in the element definition, which is 500mm. Set the ‘Lower Limit’ as 50mm and ‘Upper Limit’ as 500mm.

Switch to ‘Performance’ page. In the first Row, Select ‘Max Displacement’ in the ‘Objective/Constraint’. Select ‘Upper Limit’ in the Type. Input the Current value (Refer to PART1) as 3.898837. Set the ‘Limit Value’ as 20.

Click ‘Add Row’. Select ‘Volume’ in Objective/Constraint’. Select ‘Minimize’ in Type. Input 456570000000 in ‘Current Value’ (Refer to PART1). Input ‘0’ in ‘Limit Value’

Click ‘Analysis’ and then ‘Perform Design Optimization’ to start the process of design optimization.

Wait until the analysis is completed.

Press ‘Done’ when the analysis is completed.

Click ‘Results’ and then ‘Optimum result’ to view the optimum model.

The optimum model will be opened in a new file.

Double click the ‘Element Definition’. The thickness of the material is atomically set to the optimum thickness, 152mm.

Switch to the page of ‘Results’

Stress is 13.46344N/sq mm which is lower than the upper limit of the stress.

Displacement is 11.28277mm which is an acceptable value.


The design has been optimized from the thickness 500mm to 150mm which is minimum material used and within the stress limit and acceptable displacement.

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