In order to optimize conceptual lightweight structure for 2m aperture theodolite primary mirror

according minimum flexibility principle

the papers optimizes conceptual lightweight structure with FEA topology method. From the computation result

major remain radial is close for different mirror material

in which the outside radial is 889.5mm

the inner is 235mm

the middle radial places are 720-730mm

620-630mm; the mean lightweight rate of non-circular type is about 70%

the circular is to 50%. From optimization data of Zerodur mirror

natural frequency comes to 300Hz

location reaction force declines largely relatively. Comparing the deformation of SiC mirror surface with uniform lightweight structure

the displacement of non-uniform circular structure and close hexagon structure is close to 0.42-0.45e-5mm

while the uniform circular and open hexagon is 0.58-0.59e-5mm; and the natural frequency of uniform distribution circular is 1200Hz

while the non-uniform is 1680Hz

and the hexagon 1620-1670Hz. We get the conclusion

for the gravity load on mirror surface distributes nonlinear

the distribution of lightweight structure is uniform

which helps to control mirror surface deformation and natural frequency

to referent to lightweight design.